UNDERSTANDING PTSD AND MAJOR DEPRESSIVE DISORDER

CO-OCCURRENCE:

STRUCTURAL RELATIONS AMONG DISORDER CONSTRUCTS AND TRAIT

AND SYMPTOM DIMENSIONS

by

LOREN M. POST

Submitted in partial fulfillment of the requirements

for the degree of Master of Arts

Thesis Advisor: Dr. Norah C. Feeny

Department of Psychology

CASE WESTERN RESERVE UNIVERSITY

January, 2010

CASE WESTERN RESERVE UNIVERSITY

SCHOOL OF GRADUATE STUDIES

We hereby approve the thesis/dissertation of

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candidate for the ______degree *.

(signed)______(chair of the committee)

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*We also certify that written approval has been obtained for any proprietary material contained therein. 1

Table of Contents

Abstract...... 4 Introduction...... 5 Method ...... 18 Results...... 24 Discussion...... 27 References...... 44

2

List of Tables

Table 1: Mean, Standard Deviation, and Range on Model Measures ...... 37 Table 2: Zero Order Correlations Among Measured Variables...... 38 Table 3: Completely Standardized Factor Loadings of Model Indicators...... 39 Table 4: Unstandardized and Standardized Structural Regression Coefficients for Final Model...... 40 3

List of Figures

Figure Captions...... 41 Figure 1: Hypothesized Model: Relations Among PTSD and Major Depressive Disorder Constructs and Trait and Symptom Dimensions ...... 42 Figure 2: Final Model: Relations Among PTSD and Major Depressive Disorder Constructs and Trait and Symptom Dimensions with Standardized Coefficients...... 43

4

Understanding PTSD and Major Depressive Disorder Co-occurrence:

Structural Relations Among Disorder Constructs and Trait and Symptom Dimensions

Abstract

by

LOREN M. POST

PTSD and major depressive disorder co-occur at high rates. This co-occurrence has been associated with greater disorder severity and functional impairment. In order to better understand the nature of this co-occurrence, this study examined the structural relations among the disorders and trait and symptom dimensions within the framework of the integrative hierarchical model of anxiety and depression. Results suggest that PTSD and major depressive disorder are best conceptualized as two distinct, yet strongly related constructs. The trait negative affect/neuroticism construct had a direct effect on both

PTSD and major depressive disorder, partly explaining the overlap between the disorders.

The trait positive affect/extraversion construct had a unique, negative direct effect on major depressive disorder and PTSD had a unique, direct effect on the physical concerns symptom construct. A clearer understanding of the trait vulnerabilities and symptoms involved in co-occurrence may help to inform both diagnostic classification and treatment.

5

Introduction

Posttraumatic stress disorder (PTSD) is classified as an anxiety disorder in the

Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR; American

Psychiatric Association, 2000). As with most of the anxiety disorders, PTSD has high rates of lifetime association and co-occurrence (defined as “the simultaneous presence in an individual of two diagnoses, which are not necessarily correlated to an appreciable extent within the population;” Lilienfeld, Waldman, & Israel, 1994, p. 78) with major depressive disorder (e.g., Breslau, Davis, Andreski, & Peterson, 1991). In the National

Comorbidity Survey (Kessler, Sonnega, Bromet, Hughes, & Nelson, 1995) for example, across all disorders, major depressive disorder showed the highest rate of lifetime association with PTSD among women (48.5%) and the second highest rate among men

(47.9%). High rates of co-occurring PTSD and major depressive disorder have also been found across different trauma exposed populations, such as combat veterans (95% lifetime and 50% co-occurring; Bleich, Koslowsky, Dolev, & Lerer, 1997), motor-vehicle accident survivors (53% co-occurring; Blanchard, Buckley, Hickling, & Taylor, 1998), and physical assault survivors (49% co-occurring; Nixon, Resick, & Nishith, 2004).

Moreover, there appears to be a synergistic aspect to the co-occurrence of PTSD and major depressive disorder, as individuals with co-occurring PTSD and major depressive disorder tend to display more severe symptoms of both disorders and worse functional impairment than individuals with either PTSD or major depressive disorder alone (Blanchard et al., 1998; Momartin, Silove, Manicavasagar, & Steel, 2004; Nixon et al., 2004; Shalev et al., 1998). Further, this co-occurrence is associated with a number of negative correlates and outcomes including increased risk for attempted suicide 6

(Oquendo et al., 2005), a more chronic course of impairment and psychopathology

(Breslau et al., 1991), and attenuated treatment response (Green et al., 2006). Thus, a closer examination of PTSD and major depressive disorder co-occurrence is warranted in order to better understand the shared and unique vulnerability and symptom dimensions driving the high rates of co-occurrence and related disorder severity.

To date, examining the nature of the co-occurrence of PTSD and major depressive disorder has been approached in several ways. There has been exploration of the overlapping PTSD and major depressive disorder diagnostic criteria (i.e., insomnia, impaired concentration, and anhedonia) possibly contributing to the high rates of diagnostic co-occurrence. For instance, among a sample of combat veterans, Bleich et al.

(1997) demonstrated that when shared symptoms were eliminated from the diagnostic criteria, there were relatively small changes in the diagnostic frequency for each disorder.

Indeed, of those originally diagnosed with lifetime and current major depressive disorder,

98% and 93% were still diagnosed as such, respectively, after overlapping symptom removal. The rates of maintaining the PTSD diagnosis were lower, with 70% still diagnosed as having lifetime PTSD and 55% still diagnosed as having current PTSD.

Such findings suggest that PTSD may be more often accounted for by major depressive disorder than major depressive disorder is by PTSD. Overall, however, symptom overlap appears to have only a moderate effect on rates of PTSD, as over half of the participants maintained their lifetime and current diagnosis. Therefore, these results suggest that

PTSD may be a distinct diagnosis co-occurring with major depressive disorder, despite symptom overlap. In further examining symptom overlap, Blanchard and colleagues

(1998) investigated the possibility that co-occurrence may be due to the fact that after 7 accounting for the three symptoms shared with PTSD only two of the remaining six major depressive disorder symptom criteria are needed for the diagnosis of major depressive disorder. Therefore, in diagnosing co-occurring major depressive disorder among individuals with PTSD, it was suggested that four to five additional major depressive disorder symptom criteria, as opposed to just two, be met. However,

Blanchard et al. (1998) found that individuals with PTSD who endorsed more major depressive disorder symptoms (i.e., 7-9) compared to those who endorsed fewer major depressive disorder symptoms (i.e., 5-6) displayed similar levels of subjective distress and impairment. Because co-occurrence has been associated with disorder severity (e.g.,

Kessler, Chiu, Demler, & Walters, 2005), these results suggest that symptom overlap is an insufficient explanation for PTSD and major depressive disorder co-occurrence.

Beyond the explanation that observed high rates of co-occurring PTSD and major depressive disorder are due to overlapping symptoms, others have investigated whether

PTSD and major depressive disorder represent two distinct constructs, or whether their co-occurrence represents a single general traumatic stress construct. For instance,

Blanchard and colleagues (1998) conducted factor analyses using measures of PTSD and major depressive disorder symptomatology to evaluate and compare how a single-factor model of posttraumatic stress symptoms (i.e., unitary response to trauma) and a two- factor model of posttraumatic stress symptoms (i.e., PTSD and major depressive disorder) fit the data for their traumatized population. The model fit indices were improved by the two-factor model relative to the single-factor model. Additionally, when directly comparing the two models, the two-factor model accounted for the data more adequately than the single-factor model. However, within the two-factor model, the 8 separate PTSD and major depressive disorder factors were still strongly correlated. Thus, although sharing many features, PTSD and major depressive disorder can be viewed as two distinct responses to trauma. In a recently published study, Grant, Beck, Marques,

Palyo, and Clapp (2008) examined the latent structure of PTSD, major depressive disorder, and generalized anxiety disorder among individuals who experienced a serious motor-vehicle accident. Confirmatory factor analyses suggested that a model with PTSD, major depressive disorder, and generalized anxiety disorder as three distinct constructs fit the data better than a model with the three disorders as one general traumatic stress construct. Again, however, the association between the PTSD and major depressive disorder factors was extremely high. These findings suggest that co-occurring PTSD and major depressive disorder may be best conceptualized as two independent, yet highly overlapping constructs. Somewhat in contrast, when exploring predictors of PTSD versus co-occurring PTSD and major depressive disorder, O’Donnell, Creamer, and Pattison

(2004) found nearly identical sets of predictor variables for each, suggesting that PTSD and co-occurring PTSD and major depressive disorder may be essentially the same construct. Interestingly, a different set of predictors differentiated major depressive disorder from both PTSD and co-occurring PTSD and major depressive disorder. Such results demonstrate that depression may exist as a distinct construct separate from a more general traumatic stress construct shortly after a traumatic event (O’Donnell et al., 2004).

Overall, it is still unclear whether the high rates of co-occurring PTSD and major depressive disorder can be attributed to two overlapping, yet distinct constructs or a single construct in which the disorders are essentially indistinguishable. Determining whether PTSD and major depressive disorder represent distinct responses to trauma or a 9 general traumatic stress response is an important step in understanding the nature of their co-occurrence.

Examination of the latent structure of PTSD and major depressive disorder within a structural model of co-occurrence is one way to further investigate the possible overlapping and specific features of the disorders. From a more general perspective, structural models have been proposed to explain the co-occurrence between anxiety and mood disorders. The tripartite model of anxiety and depression (Clark & Watson, 1991) for example, proposes that high levels of negative affect, a general dimension of subjective distress and dissatisfaction, is the common underlying factor contributing to co-occurring anxiety and depression. Further, positive affect, a general dimension of positive mood states, differentiates depression from the anxiety disorders, as the underlying positive affect factor has stronger negative associations with depression than with anxiety. Finally, autonomic arousal is a specific anxiety factor distinguishing the anxiety disorders from depression.

Although the tripartite model has been well supported (e.g., Watson, Clark, et al.,

1995; Watson, Weber, et al., 1995), additional research has demonstrated that low

positive affect is not only related to depression, but also social phobia (Brown,

Chorpita, & Barlow, 1998; Hughes et al., 2006). Further, autonomic arousal may only

be a specific feature of panic disorder, rather than an underlying factor of all anxiety

disorders (Brown et al., 1998). Indeed, the hierarchical model of the anxiety disorders

(Zinbarg & Barlow, 1996) proposes that each anxiety disorder consists of a higher order

negative affect component and a specific lower order component that distinguishes the

anxiety disorders from each other. Building on prior models, Mineka, Watson, and 10

Clark (1998) proposed an integrative hierarchical model of anxiety and depression that integrates key features of the tripartite model (Clark & Watson, 1991) with the hierarchical model of the anxiety disorders (Zinbarg & Barlow, 1996). In this model, the negative affectivity component is a higher order factor present at varying levels in each mood and anxiety disorder and is responsible for the overlap among these disorders. Additionally, each mood and anxiety disorder has a relatively unique component (e.g., anxious arousal is the specific component of panic disorder) that differentiates it from all of the others.

Numerous studies have investigated the underlying structure of PTSD symptoms partly in response to the questioned validity of the three-cluster symptom structure specified by the DSM-IV (i.e., reexperiencing, avoidance-numbing, and hyperarousal;

Simms, Watson, & Doebbeling, 2002). Resulting models have included variations of two to four factor symptom structures (e.g., Amdur & Liberzon, 2001; Asmundson et al., 2000; Buckley, Blanchard, & Hickling, 1998; Cordova, Studts, Hann, Jacobsen, &

Andrykowski, 2000; King, Leskin, King, & Weathers, 1998). Drawing on evidence that the anxiety and mood disorders share a general distress component, Simms and colleagues (2002) developed and tested a four-factor model of PTSD symptoms with a dysphoria or general negative affectivity factor. More specifically, the authors conducted confirmatory factor analyses to compare 6 structural models of PTSD symptoms. The symptom structural model that provided the best fit to the data consisted of four factors: intrusions, avoidance, hyperarousal (consisting of two of the DSM-IV hyperarousal symptoms: hypervigilance and exaggerated startle response), and dysphoria (consisting of the DSM-IV emotional numbing symptoms and three of the 11

DSM-IV hyperarousal symptoms: sleep disturbance, irritability, and impaired concentration). Correlations between symptom scales constructed to represent each of the four PTSD symptom factors and external measures of psychopathology revealed that the depression and generalized anxiety disorder measures were more strongly correlated with the dysphoria scale than with the other PTSD symptom scales and that the strongest relationship was between the dysphoria scale and depression measure.

Therefore, the dysphoria factor may represent the nonspecific negative affect component common to anxiety and mood disorders. Recent research has further supported the presence of a dysphoria factor within the structure of the PTSD symptoms

(Baschnagel, O’Connor, Colder, & Hawk, 2005; Krause, Kaltman, Goodman, &

Dutton, 2007) and the dysphoria factor having the strongest correlations with measures of depression, state anger, and general psychological distress (Palmieri, Weathers,

Difede, & King, 2007).

In line with the above findings, structural analyses of anxiety and mood disorders based on dichotomous data have shown that PTSD has a stronger loading on a general distress construct (also defined by major depressive disorder, dysthymia, and generalized anxiety disorder) than it does on a fear construct (defined by agoraphobia, panic disorder, simple phobia, and social phobia; Cox, Clara, & Enns, 2002; Slade &

Watson, 2006). Overall, these results suggest that PTSD includes a core general distress component that may be responsible for the high rates of PTSD and major depressive disorder co-occurrence.

The general distress or negative affect component shared between PTSD and major depressive disorder may reflect a common etiological influence underlying the 12 symptom expression of the disorders. More generally, the negative affect and positive affect components proposed in the structural models of co-occurrence may be characteristic of trait negative affect/neuroticism and trait positive affect/extraversion, respectively (Clark, Watson, & Mineka, 1994; Mineka et al., 1998). Thus, trait negative affect/neuroticism may play a causal role in the development of both the anxiety and mood disorders and low trait positive affect/extraversion may play a causal role in the development of depression.

The autonomic arousal component identified in the structural models of co- occurrence is less clearly characteristic of a vulnerability dimension (Brown et al.,

1998; Clark et al., 1994). Rather, autonomic arousal is likely to simply be a symptom feature of anxiety, particularly panic disorder (Brown et al., 1998; Clark & Watson,

1991). The construct of anxiety sensitivity, however, may be a trait vulnerability in the development of various anxiety disorders. Anxiety sensitivity refers to the fear of anxiety symptoms based on beliefs that these symptoms have harmful consequences

(McNally, 1999). Thus, an individual with high anxiety sensitivity will tend to respond fearfully to his or her own anxiety symptoms. The Anxiety Sensitivity Index (ASI;

Reiss, Peterson, Gursky, & McNally, 1986) is a widely accepted measure of the anxiety sensitivity construct. Factor analyses of the ASI have revealed that the anxiety sensitivity construct is multidimensional. More specifically, the anxiety sensitivity construct appears to be comprised of three lower order factors corresponding to physical concerns, mental incapacitation concerns, and social concerns that all load on a higher order factor of general anxiety sensitivity (e.g., Rodriguez, Bruce, Pagano, Spencer, &

Keller, 2004; Zinbarg, Barlow, & Brown, 1997). There is a great deal of evidence 13 supporting the association between anxiety sensitivity and anxiety disorders, specifically panic disorder (see Taylor, 1999, for a review). Further, studies have examined associations between the specific anxiety sensitivity dimensions and anxiety and mood disorders (e.g., Taylor, Koch, Woody, & McLean, 1996; Zinbarg et al., 1997;

Zinbarg, Brown, Barlow, & Rapee, 2001). For example, Rodriguez and colleagues

(2004) conducted multiple regressions and found the diagnosis of panic disorder with agoraphobia to be most significantly associated with increased physical concerns, major depressive disorder with increased mental incapacitation concerns, and social phobia with increased social concerns. Many of these studies, however, were not designed to determine the direction of causality. Thus, there is still question as to whether high anxiety sensitivity is a risk factor for the development of anxiety and mood disorders or a consequence of the disorders. Perhaps, similar to the autonomic arousal symptom component, physical concerns may be regarded as a specific symptom feature of certain anxiety disorders.

Studies have examined the role of the possible trait negative affect/neuroticism and low trait positive affect/extraversion vulnerabilities in the development of PTSD specifically. For example, prospective studies employing pretrauma trait assessment found that trait negative affect/neuroticism predicted (Bramsen, Dirkzwager, & van der

Ploeg, 2000) or was associated with (O’Toole, Marshall, Schureck, & Dobson, 1998) the later development of PTSD following combat related traumatic events. Additionally, although limited by its posttrauma prospective design, Fauerbach, Lawrence, Schmidt,

Munster, and Costa (2000) found that burn survivors who later developed PTSD were significantly higher in neuroticism and lower in extraversion shortly after experiencing 14 the trauma relative to those who did not develop PTSD. It is important to note that the

“low levels” of extraversion shown to be a possible risk factor in the development of

PTSD fell within the low-average range relative to a normative sample. Thus, although lower levels of extraversion may play a role in the development of PTSD, extremely low levels or absence of trait positive affect/extraversion may be the vulnerability factor specific to major depressive disorder.

Studies have also examined the relationship among anxiety sensitivity and its dimensions and PTSD. For instance, Taylor, Koch, and McNally (1992) compared levels of anxiety sensitivity across the DSM-III-R anxiety disorders and found that both

PTSD and panic disorder had higher levels than the other anxiety disorders. There was no significant difference in overall anxiety sensitivity level between PTSD and panic disorder. In another study, female survivors of intimate partner violence diagnosed with

PTSD were found to have higher levels of total anxiety sensitivity and physical concerns than survivors with no PTSD and women with no history of severe trauma

(Lang, Kennedy, & Stein, 2002). Additionally, overall anxiety sensitivity scores and specific physical concerns scores were strongly correlated with PTSD symptom severity. Although research suggests that panic disorder is strongly associated with the physical concerns dimension (e.g., Rodriguez et al., 2004), symptoms specific to a disorder must be viewed in relative rather than absolute terms (Mineka et al., 1998).

Thus, it is unlikely that physical concerns will be unique to only panic disorder.

Different configurations and varying levels of physical concerns may be important in distinguishing both PTSD and panic disorder from the other anxiety disorders. 15

Although the roles of trait negative affect/neuroticism, low trait positive affect/extraversion, and physical concerns (or autonomic arousal) have been examined in PTSD, few studies have attempted to investigate whether these dimensions can be used to explain the complicated relationship between co-occurring PTSD and major depressive disorder. In fact, when relationships among tripartite model factors (i.e., negative affect, positive affect, and autonomic arousal) and the anxiety and mood disorders have been explored, PTSD has typically not been included in the analyses. For instance, Brown and colleagues (1998) investigated the relationships among the potential trait vulnerabilities (i.e., trait negative and positive affect), the symptom dimension of autonomic arousal, and the anxiety and mood disorders (i.e., depression, generalized anxiety disorder, panic disorder/agoraphobia, obsessive compulsive disorder, and social phobia). More specifically, when structural models of the relationships among the various DSM-IV disorder factors and tripartite factors were compared among a large sample of patients with anxiety and mood disorders, the best fitting model entailed trait negative affect as a higher order factor with significant paths to each of the DSM-IV disorder factors and trait positive affect as a higher order factor with significant negative paths to depression and social phobia. Additionally, only the panic disorder/agoraphobia and generalized anxiety disorder factors had significant paths to the lower order factor of autonomic arousal (the path from the generalized anxiety disorder factor indicated that an increase in generalized anxiety disorder symptoms was associated with a decrease in autonomic arousal), suggesting that this tripartite component is a discriminating feature for only certain anxiety disorders.

Extrapolating to the co-occurrence of PTSD and major depressive disorder, this study 16 suggests that trait negative affect may be a higher order factor common to PTSD and depression, trait positive affect may be a higher order factor specific to depression, and autonomic arousal may be a symptom dimension specific to PTSD. Indeed, although trait positive affect and major depressive disorder were not included in the analyses, one study found that trait negative affect accounted for all of the covariance among PTSD and other anxiety disorders and that PTSD, in addition to panic disorder with and without agoraphobia, had a significant direct effect on the lower order autonomic arousal factor (Brown & McNiff, 2009).

To this author’s knowledge, there has been only one study published that has examined the relationships among the possible trait vulnerabilities and PTSD and major depressive disorder (Gamez, Watson, & Doebbeling, 2007). This study examined mood and anxiety disorders in relation to higher order personality traits among a sample of

Gulf War veterans. Results showed that trait negative affect/neuroticism had the strongest associations with major depressive disorder and PTSD, suggesting that PTSD can be linked conceptually to major depressive disorder through this negative emotionality trait vulnerability. Additionally, trait positive affect/extraversion had a stronger negative correlation with major depressive disorder than with PTSD, suggesting that low positive emotionality may be a trait vulnerability that is more specific to the development of major depressive disorder.

Although research has begun to consider the roles of trait negative affect/neuroticism and low trait positive affect/extraversion in the individual development of PTSD and major depressive disorder, a more thorough investigation of the nature of PTSD and major depressive disorder co-occurrence is needed. 17

Specifically, it would be useful to examine this relationship within a structural model of

co-occurrence, such as the previously described integrative hierarchical model of

anxiety and depression (Mineka et al., 1998). In doing so, a framework for

understanding the co-occurrence of PTSD and major depressive disorder can be

established and the common component that is responsible for the overlap between

these disorders and the unique components that allow the disorders to be distinguished

can be thoroughly identified.

Aims and Hypotheses

In an effort to enhance our understanding of co-occurring PTSD and major

depressive disorder, the present study’s major aims are to examine among a sample of

men and women with chronic PTSD (1) whether PTSD and major depressive disorder

are better conceptualized as two distinct responses to trauma or as a single general

traumatic stress response and (2) the roles of the trait negative affect/neuroticism and

trait positive affect/extraversion constructs and the physical concerns symptom

dimension in the co-occurrence of PTSD and major depressive disorder.

Aim 1 Hypothesis. It is hypothesized that PTSD and major depressive disorder

will represent two distinct, yet strongly correlated constructs. This hypothesis is based

on prior study results supporting a two-factor model of PTSD and major depressive

disorder, with strong correlations between the two factors (Blanchard et al., 1998; Grant

et al., 2008).

Aim 2 Hypotheses. The predicted structural relations among the disorder, trait, and

symptom dimensions include the following hypotheses: (a) trait negative

affect/neuroticism will be a higher order factor with significant paths to PTSD and 18

major depressive disorder; (b) trait positive affect/extraversion will be a higher order

factor with a significant negative path to major depressive disorder, but not PTSD; (c)

physical concerns will be a lower order symptom feature specific to PTSD, but not

major depressive disorder. Thus, the PTSD and major depressive disorder constructs

will be associated by the trait negative affect/neuroticism factor, yet distinguished by

the trait positive affect/extraversion and physical concerns factors. These hypotheses are

in line with prior theory and research suggesting that negative affect and positive affect

represent trait vulnerabilities in the development of anxiety and mood disorders, and

that each anxiety and mood disorder is likely to have a specific component that

distinguishes it from the others (Brown et al., 1998; Clark et al., 1994; Mineka et al.,

1998).

Method

Participants

The sample consisted of 200 men and women who were recruited through community advertisements and local clinical referrals. Seventy-six percent (75.5%) of the sample was female. Participants mean age was 37.41 (SD = 11.30) years. The sample was

65.0% Caucasian, 21.5% African American, 5.0% Asian, 2.5% American Indian or

Alaska Native, and 6% of other racial/ethnic backgrounds. In terms of education, 70% did not have a four year college degree. Twenty-six percent (25.5%) were unemployed.

Forty-nine percent (48.5%) earned less than $20,000 per year.

Participants experienced their identified target trauma at a mean age of 25.66 (SD

= 14.62) years. Upon entering the study, a mean of 11.97 (SD = 12.69) years had passed 19 since the target trauma occurred. In regard to type of target trauma, 48.5% were sexual assault (17.5% childhood and 31.0% adult), 29.0% physical assault (6.5% childhood and

22.5% adult), 12.5% serious accident, 2.5% combat/war, 1% natural disaster, and 6.5% other traumatic events (e.g., sudden death of loved one, witness to murder). Eighty-six percent (85.5%) reported experiencing more than one DSM-IV Criteria A event. Of the

200 participants with a primary diagnosis of PTSD, 108 (54%) were diagnosed with current co-occurring major depressive disorder.

Inclusion criteria were a primary DSM-IV diagnosis of current chronic PTSD and age between 18 and 65 years. Exclusion criteria included a current diagnosis of schizophrenia, delusional disorder, medically unstable bipolar disorder, depression severe enough to require immediate psychiatric treatment (e.g., actively suicidal), or substance dependence. Participants were also excluded if they were in an ongoing intimate relationship with the perpetrator (in assault cases). Ineligible participants were offered appropriate referrals.

Measures

PTSD Symptom Scale – Interview (PSS-I). The PSS-I (Foa, Riggs, Dancu, &

Rothbaum, 1993) is a semi-structured interview assessing PTSD diagnosis and severity and was used in this study to obtain a diagnosis of primary chronic PTSD. The measure consists of 17 items corresponding to the DSM-IV PTSD symptoms. The items form three clusters: reexperiencing, avoidance, and hyperarousal. Items are rated on a 0-3 scale for combined frequency and severity in the past two weeks (0 = not at all, 3 = 5 or more times per week/very much). The PSS-I has good convergent validity with other PTSD interview measures (r = .73 and .87; Foa & Tolin, 2000). Interrater reliability for PTSD 20 diagnosis (k = .91) and overall severity (r = .97) ratings are excellent (Foa et al., 1993). In this study, the PSS-I was used as an indicator for the PTSD latent variable.

PTSD Symptom Scale – Self-Report (PSS-SR). The PSS-SR (Foa et al., 1993) is a

17-item self-report version of the PSS-I. Each symptom is rated on a 4-point scale from 0

(not at all) to 3 (very much), with higher scores indicating more severe PTSD symptoms.

Foa et al. (1993) demonstrated this measure to have high internal consistency (α = .91), excellent interrater reliability for PTSD diagnosis (κ = .91) and overall severity (r = .97), and good test-retest reliability for the total score (r = .83). In this study, the PSS-SR was used as an indicator for the PTSD latent variable.

Hamilton Rating Scale for Depression (HAM-D). The HAM-D (Hamilton, 1960) is an interviewer-rated depressive symptom scale consisting of 24 items measuring the severity of cognitive, behavioral, and somatic symptoms of depression in the past week.

Items are scored on either a 0-2 or 0-4 spectrum, with higher scores indicating greater severity. The HAM-D has excellent interrater reliability (r = .90) and good internal consistency (α = .76; Rehm & O’Hara, 1985), and adequate convergent validity with a wide range of depression measures (Bagby, Ryder, Schuller, & Marshall, 2004). In this study, the HAM-D was used as an indicator for the major depressive disorder latent variable.

Beck Depression Inventory (BDI). The BDI (Beck, Ward, Mendelsohn, Mock, &

Erbaugh, 1961) is a 21-item self-report inventory measuring depression severity over the past week. Each item consists of four self-evaluative statements scored 0 to 3, with increasing scores indicating greater severity of depression. The BDI has a split-half reliability of .93 (Beck et al., 1961) and correlates strongly with clinical ratings of 21 depression (r = .55 to .96; Beck, Steer, & Carbin, 1988). In this study, the BDI was used as an indicator for the major depressive disorder latent variable.

Positive and Negative Affect Schedule (PANAS). The PANAS (Watson, Clark, &

Tellegen, 1988) consists of two 10-item scales measuring the two primary dimensions of mood – Positive Affect (PANAS-P) and Negative Affect (PANAS-N). Participants rate on a 5-point scale (1 = very slightly or not at all, 5 = extremely) to what extent they experience each mood state in general. The PANAS scales are stable over a 2-month time period (α, .47 to .68 for Positive Affect and .39 to .71 for Negative Affect), highly internally consistent (α, .86 to .90 for Positive Affect and .84 to .87 for Negative Affect), and largely uncorrelated (r = -.12 to -.23; Watson et al., 1988). The PANAS has high convergent validity with lengthier measures of mood (r = -.19 to -.36 for Positive Affect and .51 to .74 for Negative Affect; Watson et al., 1988). In this study, the PANAS-P and

PANAS-N were used as indicators for the positive affect and negative affect latent variables, respectively.

Big Five Inventory (BFI). The BFI (John, Donahue, & Kentle, 1991) is a 44-item self-report instrument assessing the five dimensions of personality (i.e., Extraversion,

Agreeableness, Conscientiousness, Neuroticism, and Openness). Each item consists of a short statement that participants rate on a 5-point scale (1 = disagree strongly, 5 = agree strongly). Each personality dimension scale includes eight to ten items. The alpha reliabilities of the BFI scales typically range from .75 to .90 and average above .80; 3- month test-retest reliabilities range from .80 to .90, with a mean of .85 (John &

Srivastava, 1999). The BFI shows substantial convergent validity with other Big Five instruments (Trait Descriptive Adjectives, mean r = .81 and NEO-Five Factor Inventory, 22 mean r = .73; John & Srivastava, 1999). In this study, the BFI Extraversion and

Neuroticism scales were used as indicators for the positive affect and negative affect latent variables, respectively.

Anxiety Sensitivity Index (ASI). The ASI (Reiss et al., 1986) is a 16-item self- report measure assessing the construct of anxiety sensitivity (i.e., the fear of anxiety symptoms based on beliefs that these symptoms have harmful somatic, psychological, or social consequences). Each item is rated on a five-point scale ranging from 0 (very little) to 4 (very much). As previously discussed, the ASI structure is best regarded as hierarchical with three first order factors (i.e., Physical Concerns, Mental Incapacitation

Concerns, and Social Concerns) loading on a single, general higher order factor (i.e.,

Anxiety Sensitivity; Zinbarg et al., 1997). The total ASI scale and the Physical Concerns subscale have adequate test-retest reliability (r = .72 and .64, respectively; Rodriguez et al., 2004). The Physical Concerns subscale is highly internally consistent (α = .89;

Zinbarg & Barlow, 1996). In this study, the Physical Concerns subscale (as constructed by Zinbarg et al., 1997) was used as an indicator for the physical concerns latent variable.

The Physical Concerns subscale includes the following items: It scares me when I feel

“shaky” (trembling) (Item 3); It scares me when I feel faint (Item 4); It scares me when my heart beats rapidly (Item 6); It scares me when I am nauseous (Item 8); When I notice that my heart is beating rapidly, I worry that I might have a heart attack (Item 9); It scares me when I am short of breath (Item 10); When my stomach is upset, I worry that I might be seriously ill (Item 11); Unusual body sensations scare me (Item 14).

Structured Clinical Interview for DSM-IV Axis I (SCID-I). The SCID-I (First,

Spitzer, Gibbon, & Williams, 2001) is a diagnostic interview used to acquire information 23 about DSM-IV Axis I disorder criteria. The SCID-I has acceptable joint interview interrater reliability with kappas between .57 and 1.0 (Zanarini et al., 2000). In this study, the SCID-I was used to obtain a diagnosis of current major depressive disorder.

Procedure

The data for this paper came from a treatment study for chronic PTSD. Initial eligibility was determined through a semi-structured phone screen, and potentially eligible participants were scheduled for an intake evaluation. After informed consent procedures, an independent evaluator conducted the intake evaluation consisting of structured interviews (PSS-I, HAM-D, SCID-I). Following the intake evaluation, eligible participants completed self-report measures (PSS-SR, BDI, PANAS, BFI, ASI).

Statistical Plan

The raw data were analyzed using Amos 7.0 (Arbuckle, 2006) with maximum likelihood estimation. Missing data were imputed using mean substitution, with 7.5% of cases having three or less missing items in a measure. Figure 1 displays the hypothesized model. Ovals represent latent variables and rectangles represent measured variables. The exogenous (i.e., independent) latent variables were the Negative Affect and Positive

Affect constructs. As described above, the PANAS-N and the BFI Neuroticism scales and the PANAS-P and the BFI Extraversion scales were used as indicators of the Negative

Affect and Positive Affect latent variables, respectively. The endogenous (i.e., dependent) latent variables were the PTSD and Depression constructs and the Physical

Concerns construct. The PSS-I and PSS-SR were used as indicators of the PTSD latent variable and the HAM-D and BDI were used as indicators of the Depression latent variable. The Physical Concerns latent variable was assessed with a single indicator, the 24

Physical Concerns subscale of the ASI. Because of the need for at least two indicators per latent variable to prevent model underidentification, the Physical Concerns subscale items were randomly split-halved. Figure 1 illustrates the hypothesis that PTSD and

Depression are two distinct constructs. Additionally, Negative Affect directly affects

PTSD and Depression, Positive Affect directly affects Depression, and PTSD directly affects Physical Concerns.

Model fit was assessed on the values of more than one model fit index because a single index reflects only a particular aspect of model fit (Kline, 2005). Model fit was evaluated with the chi-square goodness-of-fit statistic, the normed chi-square (NC), the goodness-of-fit index (GFI), the comparative-fit index (CFI), and the root mean square error of approximation (RMSEA) and its 90% confidence interval and test of close fit

(CFit). A good fitting model may be indicated when the NC is less than 2 (Tabachnick &

Fidell, 1996). A cutoff value of .95 or above for GFI and CFI and a cutoff value of .06 or below for RMSEA (90% CI upper limit close to or less than .06, nonsignificant CFit) indicate good model fit (Hu & Bentler, 1998).

Results

Model Fit

The mean, standard deviation, and range of the measured variables are displayed in Table 1. The participants displayed moderate to severe PTSD and depression. The zero order correlations among measured variables are displayed in Table 2.

When the hypothesized model (see Figure 1) was tested using maximum likelihood estimation, the PTSD disturbance (D1) and Depression disturbance (D2) had 25 an estimated covariance matrix that was nonpositive definite. Disturbance represents unexplained variance in the latent endogenous variables (e.g., PTSD and Depression) due to unmeasured causes. The associated PTSD and Depression disturbance correlation was

1.08. The standardized residual covariances and modification indices were examined in order to determine if this illogical correlation coefficient was caused by model misspecification.

A standardized residual above 2 generally indicates that the model underexplains a relationship between two variables (Raykov & Marcoulides, 2006). The standardized residual covariance between the PSS-I and HAM-D was 2.22. Additionally, a high modification index (the model’s chi-square value would be approximately 24.79 units lower if the modification was made) suggested that the PSS-I and HAM-D error covariance (e3, e7) be estimated. The suggested error covariance estimate possibly represents unaccounted for method variance that is not explained by the PTSD and

Depression latent variables, such as a shared clinician-rated method of measurement.

Thus, in order to resolve the nonpositive definite problem and permit a clearer interpretation of results, the method variance was incorporated into the model by correlating error between the clinician-rated PSS-I and HAM-D indicators.

The hypothesized model was refitted to the data with this adjustment. In the refitted hypothesized model the correlation between the PTSD and Depression disturbance was .86, p < .001, and the nonpositive definite problem was resolved. The correlated error between the PSS-I and HAM-D was .46, p < .001. The indices of overall model fit indicated that the revised hypothesized model provided an adequate fit to the data, χ² (28, N = 200) = 42.88, p < .05, NC = 1.53, GFI = .96, CFI = .98, RMSEA = .05 26

(CI = .01 - .08; CFit = .43). Inspection of modification indices and standardized residuals indicated no significant strains in the model. The final model is presented in Figure 2.

As predicted, there was a strong estimated correlation between the PTSD and

Depression latent factors of .89, p < .001. In order to test the hypothesis that PTSD and major depressive disorder represent two distinct, yet strongly correlated constructs rather than a single general traumatic stress construct, a competing model with PTSD and

Depression merged as a single latent factor (i.e., General Traumatic Stress) was fitted to the data (incorporating the estimated correlated error between the PSS-I and HAM-D indicators present in the final model). The fit indices for the alternative model with the single General Traumatic Stress latent factor were χ² (30) = 61.39, p < .01, NC = 2.05,

GFI = .94, CFI = .96, RMSEA = .07 (CI = .05 - .10; CFit = .08). The alternative model resulted in a significant decrement in model fit, χ²diff (2) = 18.51, p < .001, suggesting

that PTSD and major depressive disorder are better conceptualized as two distinct

constructs.

Direct Effects

The completely standardized estimates of indicator loadings on corresponding

latent factors are reported in Table 3 (range of λs = .59 to .94; all ps < .001). In

examining proportions of explained variance, 37% of the variance in PTSD was

accounted for by Negative Affect, 56.9% of the variance in Depression was accounted for

by Negative Affect and Positive Affect, and 16.4% of the variance in Physical Concerns

was accounted for by PTSD and Negative Affect. Unstandardized and standardized

estimates of direct effects are reported in Table 4. There was a direct effect of Negative

Affect on PTSD (standardized coefficient = .61, p < .001) and on Depression 27

(standardized coefficient = .57, p < .001), suggesting that Negative Affect was predictive of these anxiety and mood disorders. The direct effect of Negative Affect on PTSD (z =

.71) and the direct effect of Negative Affect on Depression (z = .65) did not differ in their relative magnitude (p = 1.05) as determined by the z test procedure (α = .05) presented by

Meng, Rosenthal, and Rubin (1992). There was also a direct effect of Positive Affect on

Depression (standardized coefficient = -.27, p < .05), suggesting that an increase in

Positive Affect predicted a decrease in Depression. There was also a direct effect of

PTSD on Physical Concerns (standardized coefficient = .41, p < .001), suggesting that

PTSD was predictive of Physical Concerns. Finally, there was an indirect effect of

Negative Affect on Physical Concerns (standardized coefficient = .25, p < .001). Further support for the hypothesized model was demonstrated in that there were no modification indices involving potential paths from Positive Affect to PTSD or from Depression to

Physical Concerns.

Discussion

The final structural model supported the hypothesized relations among PTSD and major depressive disorder and the trait and symptom dimensions. Within the model,

PTSD and major depressive disorder were best represented as two distinct, yet strongly related constructs. The higher order trait negative affect/neuroticism had significant paths to both PTSD and major depressive disorder. The higher order trait positive affect/extraversion had a significant negative path to major depressive disorder, but not to

PTSD. There was also a significant path from PTSD to the lower order physical concerns.

Thus, trait negative affect/neuroticism was common to both PTSD and major depressive 28 disorder, while trait positive affect/extraversion and physical concerns were unique features that distinguished the two disorders.

With regard to the relationship between the disorders, results suggest that PTSD and major depressive disorder can be conceptualized as two separate constructs.

Although the strong estimated correlation between the PTSD and major depressive disorder factors suggests poor discriminant validity of these disorders, the model with

PTSD and major depressive disorder as two distinct factors was significantly better fitting than the model in which the disorders were collapsed as a single factor (i.e., general traumatic stress response). Thus, despite the considerable overlap, PTSD and major depressive disorder are likely to be best conceptualized as two distinct constructs when seen concurrently in individuals who have experienced a traumatic event. Overlap between two disorders that share a number of symptoms is to be expected. Rather than claiming the overlap to be a sign of disorder indistinctiveness, it is more useful to consider the shared component or vulnerability that may account for this overlap, while also recognizing each disorder’s unique, distinguishing features (Mineka et al., 1998).

Such a nuanced view is likely to provide more information about the relationship between PTSD and major depressive disorder than simply determining whether the disorders are separate or unitary constructs.

In the final model, trait negative affect/neuroticism was a higher order factor that directly influenced both PTSD and major depressive disorder. Thus, trait negative affect/neuroticism appears to be a common vulnerability that partly explains the relationship between PTSD and major depressive disorder. However, as indicated by the disturbance correlation between the PTSD and major depressive disorder constructs, trait 29 negative affect/neuroticism was not able to fully explain the relationship between the two disorders. Each disturbance represents unexplained variance in the PTSD and major depressive disorder constructs that is due to unmeasured causes. Therefore, the disturbance correlation suggests that there is shared variance between PTSD and major depressive disorder that cannot be explained by the common trait negative affect/neuroticism construct. This shared variance may be due to the overlapping symptom features represented in the PTSD and depression measures that were used as construct indicators. Of note, a similar disturbance correlation occurred between generalized anxiety disorder and obsessive compulsive disorder in the structural models of Brown et al. (1998) and Brown and McNiff (2009). Similar to what is proposed in the present paper, the authors suggested that negative affect was not able to fully explain the relationship among these disorders possibly due to the shared variance between measures of worry and obsessions, two essential features of generalized anxiety disorder and obsessive compulsive disorder.

Interestingly, the paths from trait negative affect/neuroticism to PTSD and major depressive disorder were not significantly different in magnitude. Trait negative affect is more strongly linked to disorders that are characterized by a substantial component of subjective distress, such as major depressive disorder and generalized anxiety disorder

(Watson, Gamez, & Simms, 2005). In the present study, the direct effects of trait negative affect/neuroticism on PTSD and major depressive disorder were similar in size, suggesting that PTSD may also be characterized by a large general distress component.

Indeed, when Watson and colleagues (2005) correlated the PTSD symptom scales constructed in the Simms et al. (2002) study (i.e., dysphoria, intrusions, hyperarousal, and 30 avoidance) with negative and positive temperament scales, the negative temperament scale had a significantly stronger correlation with the dysphoria scale than with the other

PTSD symptom scales, providing further support for the constructed dysphoria symptom dimension. Taken together, the trait negative affect/neuroticism construct influencing

PTSD is likely to be specific to the disorder’s dysphoria symptom cluster, which based on the results of the present study, appears to be similar in size to the distress component found in major depressive disorder.

While PTSD and major depressive disorder appear to be linked by trait negative affect/neuroticism, the two disorders are distinguishable by the low trait positive affect/extraversion construct. In line with earlier findings (Brown et al., 1998; Gamez et al., 2007), the present study’s structural model demonstrated that trait positive affect/extraversion was a higher order factor that had a significant negative direct effect on major depressive disorder (i.e., low positive affect is associated with increased depression). Further, the absence of a path from trait positive affect/extraversion to PTSD did not strain model fit, suggesting that such a path would not be significant. This finding is in line with an earlier study demonstrating that all constructed PTSD symptom scales

(i.e., dysphoria, intrusions, hyperarousal, and avoidance) were very weakly correlated with a positive temperament scale (Watson et al., 2005). Thus, in the presence of both

PTSD and major depressive disorder, low trait positive affect/extraversion appears to be more specifically related to major depressive disorder. From a broader perspective, the demonstrated influences of trait negative affect/neuroticism and trait positive affect/extraversion in PTSD and major depressive disorder co-occurrence fit with the 31 proposed structural models of anxiety and depression (i.e., affective models) in that negative and positive affect are differentially related to the anxiety and mood disorders.

Even after accounting for the effect of trait negative affect/neuroticism, PTSD directly influenced the physical concerns symptoms. Additionally, physical concerns appeared to be generally unrelated to major depressive disorder, as modification indices indicated no improvement in model fit with the addition of a path from the depression construct to the physical concerns factor. Thus, PTSD and major depressive disorder may be further distinguished by the PTSD specific physical concerns symptom dimension.

These results appear to parallel findings on the similar autonomic arousal symptom dimension. For instance, PTSD had a direct effect on autonomic arousal symptoms after holding negative affectivity constant (Brown & McNiff, 2009) and depression had no significant direct effect on autonomic arousal (Brown et al., 1998). Although not directly tested, there is the possibility that physical concerns, as well as general anxiety sensitivity, may be a higher order vulnerability factor in the development of PTSD.

Researchers have suggested that the tendency to respond with fear to symptoms of anxiety is thought to influence the development of PTSD (Asmundson, Coons, Taylor, &

Katz, 2002). Additionally, it has been suggested that mental incapacitation concerns are also associated with PTSD symptom severity (Feldner, Lewis, Leen-Feldner, Schnurr, &

Zvolensky, 2006). Although, Asmundson and Stapleton (2008) found that when controlling for depressive symptoms, mental incapacitation concerns was not a significant predictor of PTSD total symptom severity. Rather, mental incapacitation concerns appeared to be associated with depression and physical concerns appeared to be more relevant to PTSD. In order to better understand possible individual difference 32 factors predisposing individuals to develop PTSD and major depressive disorder, it may be useful for future studies to test alternative models that include anxiety sensitivity, physical concerns, and mental incapacitation concerns as higher order factors. That being said, the present study’s results may contribute to the understanding of the unique symptom features component of PTSD. Similar to autonomic arousal being a specific

PTSD symptom feature (Brown & McNiff, 2009), the fear of autonomic arousal symptoms resulting from the belief that they may have harmful consequences (i.e., physical concerns) may also be specific to PTSD and may help to distinguish PTSD from major depressive disorder.

When interpreting the findings of the present study, it is important to note several limitations. First, this study design did not allow for the determination of causality.

Prospective studies with pre- and post-trauma assessments would be necessary for the verification of the causal effects of trait negative affect/neuroticism and low trait positive affect/extraversion on the development and expression of PTSD and major depressive disorder. Of course this type of research is rare as it is quite difficult to obtain and follow a sample of individuals who do not initially have PTSD or major depressive disorder, but later experience a traumatic event and subsequently develop or don’t develop either of the disorders. Second, in line with the study design limitation, study participants completed self-report trait measures (i.e., PANAS and BFI) at a mean of approximately

12 years posttrauma. Thus, it is difficult to know whether the reported traits reflected enduring characteristics that were evident prior to the trauma or state changes influenced by the presence of PTSD and major depressive disorder symptoms. Indeed, researchers have noted the effects of “mood-state distortion” on trait measures (i.e., when trait self- 33 reports are affected by a participant’s current clinical state; Brown, 2007). Third, the study did not include a valid measure of autonomic arousal. The integrative hierarchical model of anxiety and depression (e.g., Mineka et al., 1998) proposes that each anxiety disorder has its own specific symptom component that differentiates it from the other anxiety disorders. Although physical concerns may be a symptom feature of PTSD, there is evidence suggesting that the specific component of PTSD is autonomic arousal (Brown

& McNiff, 2009). A measure of autonomic arousal, such as the Beck Anxiety Inventory

(Beck & Steer, 1990), would have allowed for examination of the relations between co- occurring PTSD and major depressive disorder and the tripartite factors (Clark &

Watson, 1991).

Conceptualizing PTSD and major depressive disorder co-occurrence within the integrative hierarchical model of anxiety and depression (Mineka et al., 1998) allows for an understanding of the disorders beyond the nature of their symptoms. Indeed, the model provides a framework for exploring the shared and unique underlying mechanisms in the development of PTSD and major depressive disorder. Thus, examination of the PTSD and major depressive disorder relationship may begin to be guided more by knowledge of the etiology of these disorders than by their presenting symptoms. In better understanding the mechanisms underlying this complex relationship, drastic proposals, such as eliminating symptoms from the PTSD criteria that are also part of other mood and anxiety disorders diagnostic criteria (Spitzer, First, & Wakefield, 2007), may be appropriately avoided.

The study results also have clinical implications. By recognizing that trait negative affect/neuroticism may be partly responsible for this common co-occurrence 34 following trauma, clinicians may want to address this core feature of the disorders directly. In fact, a unified intervention for emotional disorders that focuses on the treatment of “negative affect syndrome” has been suggested (Barlow, Allen, & Choate,

2004). It is possible that specific treatment protocols for PTSD or major depressive disorder do not place enough focus on this robust construct, leaving individuals vulnerable for the return of disorder co-occurrence (Brown, 2007).

Although the overlap between PTSD and major depressive disorder is considerable, disorder differentiation is useful because it has important implications for understanding clinical course, complications, and treatment (Brown, 2007). In considering the present study’s findings that major depressive disorder may be differentiated by its specific low trait positive affect/extraversion vulnerability and that this component appears to account for a significant proportion of the variance in major depressive disorder when it co-occurs with PTSD, it may be beneficial to include a treatment component focusing on increasing positive emotion and involvement in pleasant activities (i.e., positive affect) into well established PTSD treatment protocols.

For instance, prolonged exposure for PTSD combined with behavioral activation, which has been found to be efficacious in treating depression (Dimidjian et al., 2006) and possibly in reducing PTSD symptom severity (Wagner, Zatzick, Ghesquiere, &

Jurkovich, 2007), may improve treatment efficacy by targeting depression specific avoidance (Wagner et al., 2007).

Finally, the study’s findings have implications for the classification of PTSD in the upcoming DSM-V. As noted earlier, a significant proportion of the variance in PTSD was explained by trait negative affect/neuroticism and the direct effects of trait negative 35 affect/neuroticism on PTSD and major depressive disorder were nearly equal in size, suggesting the presence of a significant general distress component in PTSD. Taken together, these results appear to support the suggestion made by Watson (2005) to reclassify PTSD as a distress disorder along with major depressive disorder, dysthymic disorder, and generalized anxiety disorder. In doing so, the DSM structure would better account for the substantial influence of trait negative affect/neuroticism on the overlap between PTSD and these distress-based disorders. However, as studies investigating the

PTSD symptom structure have revealed (e.g., Simms et al., 2002), PTSD also contains anxiety disorder specific symptom dimensions, such as hyperarousal, that may have greater links to the underlying mechanism of anxiety disorders (i.e., fear; Watson, 2005) than the distress disorders. Indeed, the present study demonstrated that PTSD has an anxiety symptom feature (i.e., physical concerns) that is also specific to panic disorder.

Therefore, a reclassification of PTSD from the anxiety disorders to the distress disorders may not be completely justified. Moving beyond the present study’s findings, some investigators have suggested placing PTSD in completely different or newly constructed categories (e.g., Rosen & Lilienfeld, 2008). For instance, Resick (in press) has proposed a

“traumatic-stress disorders” category in which PTSD results from the interaction between a serious adverse life event and individual vulnerabilities to psychopathology. This proposal was partly based on a review suggesting that PTSD should not be placed with the anxiety disorders because fear does not play the primary role in the development and maintenance of PTSD. Also, PTSD should not be placed with the distress disorders based on their shared trait negative affect vulnerability because PTSD and the distress disorders are not equally likely to precede each other in order of temporal development. Clearly, 36 the classification of PTSD is a complex issue. It may be useful for future research to examine the structural relations among the empirically derived PTSD symptom dimensions, other co-occurring disorders, and trait vulnerabilities. Such analyses may help researchers to obtain a clearer understanding of the shared, unique, and interactive components in the development of PTSD, leading to a more accurate classification of the disorder within the DSM-V. 37

Table 1

Mean, Standard Deviation, and Range on Model Measures (N = 200)

Measure M SD Range

PTSD- Interview (PSS-I) 29.56 6.69 15 – 46

PTSD- Self-report (PSS-SR) 34.47 8.01 11 – 51

Depression- Interview (HAM-D) 23.73 10.30 3 – 59

Depression- Self-report (BDI) 25.03 9.78 4 – 48

Negative Affect (PANAS-N) 29.58 8.31 10 – 50

Neuroticism (BFI-N) 3.56 .76 2 – 5

Positive Affect (PANAS-P) 31.32 7.85 14 – 50

Extraversion (BFI-E) 3.04 .81 1 – 5

Physical Concerns (ASI)a 22.53 7.39 8 – 40

Note. PSS-I = Posttraumatic Stress Disorder Symptom Scale – Interview (range 0 – 51); PSS-SR =

Posttraumatic Stress Disorder Symptom Scale – Self-Report (range 0 – 51); HAM-D = Hamilton Rating

Scale for Depression (range 0 – 75); BDI = Beck Depression Inventory (range 0 – 63); PANAS-N =

Positive and Negative Affect Schedule – Negative Affect (range 10 – 50); BFI-N = Big Five Inventory –

Neuroticism (range 1 – 5); PANAS-P = Positive and Negative Affect Schedule – Positive Affect (range 10

– 50); BFI-E = Big Five Inventory – Extraversion (range 1 – 5); ASI = Anxiety Sensitivity Index (range 0 –

32). a The mean consists of the Physical Concerns items from the Anxiety Sensitivity Index.

38

Table 2

Zero Order Correlations Among Measured Variables

Variable 1. 2. 3. 4. 5. 6. 7. 8. 9.

1. PSS-I —

2. PSS-SR .53** —

3. HAM-D .62** .48** —

4. BDI .48** .67** .58** —

5. PANAS-N .35** .46** .44** .58** —

6. PANAS-P -.16* -.21** -.25** -.41** -.29** —

7. BFI-N .19** .29** .30** .42** .62** -.43** —

8. BFI-E -.04 -.13 -.19** -.27** -.29** .43** -.39** —

9. ASI- .15* .31** .17* .34** .33** -.13 .23** -.08 —

Physical

Concerns

Note. PSS-I = Posttraumatic Stress Disorder Symptom Scale – Interview; PSS-SR = Posttraumatic Stress

Disorder Symptom Scale – Self-Report; HAM-D = Hamilton Rating Scale for Depression; BDI = Beck

Depression Inventory; PANAS-N = Positive and Negative Affect Schedule – Negative Affect; PANAS-P =

Positive and Negative Affect Schedule – Positive Affect; BFI-N = Big Five Inventory – Neuroticism; BFI-

E = Big Five Inventory – Extraversion; ASI-Physical Concerns = Anxiety Sensitivity Index with Physical

Concerns items only.

* p < .05. ** p < .01.

39

Table 3

Completely Standardized Factor Loadings of Model Indicators

Latent factor and indicator Factor loading

Negative Affect

PANAS-N .87***

BFI-N .71***

Positive Affect

PANAS-P .72***

BFI-E .59***

PTSD

PSS-I .61***

PSS-SR .84***

Depression

HAM-D .64***

BDI .90***

Physical Concerns

ASI_1-Physical Concerns .89***

ASI_2-Physical Concerns .94***

Note. PANAS-N = Positive and Negative Affect Schedule – Negative Affect; BFI-N = Big Five Inventory-

Neuroticism; PANAS-P = Positive and Negative Affect Schedule – Positive Affect; BFI-E = Big Five Inventory-

Extraversion; PSS-I = Posttraumatic Stress Disorder Symptom Scale – Interview; PSS-SR = Posttraumatic Stress

Disorder Symptom Scale – Self-Report; HAM-D = Hamilton Rating Scale for Depression; BDI = Beck

Depression Inventory; ASI_1-Physical Concerns = Anxiety Sensitivity Index with Physical Concerns items 4, 6,

10, 11; ASI_2-Physical Concerns = Anxiety Sensitivity Index with Physical Concerns items 3, 8, 9, 14.

*** p < .001. 40

Table 4

Unstandardized and Standardized Structural Regression Coefficients for Final Model

Construct BSE B ß

PTSD

Negative Affect .35 .06 .61***

Depression

Negative Affect .52 .10 .57***

Positive Affect -.31 .11 -.27*

Physical Concerns

PTSD .36 .08 .41***

Negative Affect .12 .03 .25***

* p < .05. *** p < .001. 41

Figure Captions

Figure 1. Hypothesized Model: Relations Among PTSD and Major Depressive Disorder

Constructs and Trait and Symptom Dimensions. NA = Positive and Negative Affect

Schedule-Negative Affect measure; BFI_N = Big Five Inventory – Neuroticism measure;

PA = Positive and Negative Affect Schedule – Positive Affect measure; BFI_E = Big

Five Inventory-Extraversion measure; PSSSR = Posttraumatic Stress Disorder Symptom

Scale – Self-Report measure; PSSI = Posttraumatic Stress Disorder Symptom Scale –

Interview measure; BDI = Beck Depression Inventory measure; HAMD = Hamilton

Rating Scale for Depression measure; ASI_1 = Physical Concerns items 4, 6, 10, 11;

ASI_2 = Physical Concerns items 3, 8, 9, 14; e = Error; D = Disturbance.

Figure 2. Final Model: Relations Among PTSD and Major Depressive Disorder

Constructs and Trait and Symptom Dimensions with Standardized Coefficients. NA =

Positive and Negative Affect Schedule-Negative Affect measure; BFI_N = Big Five

Inventory – Neuroticism measure; PA = Positive and Negative Affect Schedule –

Positive Affect measure; BFI_E = Big Five Inventory-Extraversion measure; PSSSR =

Posttraumatic Stress Disorder Symptom Scale – Self-Report measure; PSSI =

Posttraumatic Stress Disorder Symptom Scale – Interview measure; BDI = Beck

Depression Inventory measure; HAMD = Hamilton Rating Scale for Depression measure;

ASI_1 = Physical Concerns items 4, 6, 10, 11; ASI_2 = Physical Concerns items 3, 8, 9,

14; e = Error; D = Disturbance. 42

Figure 1.

e1 e2 e5 e6 1 1 1 1

NA BFI_N PA BFI_E

Negative Positive Affect Affect

1 1 PTSD D1 Depression D2

PSSSR PSSI BDI HAMD

1 1 1 1

e4 e3 e8 e7

Physical 1 D3 Concerns

ASI_1 ASI_2

1 1

e10 e9 43

Figure 2.

e1 e2 e5 e6

-.59 NA BFI_N PA BFI_E

Negative Positive Affect Affect

-.27 .57 .61

.86

PTSD D1 Depression D2

PSSSR PSSI BDI HAMD

.41 e4 e3 e8 e7

.46 Physical D3 Concerns

ASI_1 ASI_2

e10 e9

44

References

Amdur, R. L., & Liberzon, I. (2001). The structure of posttraumatic stress disorder

symptoms in combat veterans: A confirmatory factor analysis of the Impact of

Event Scale. Journal of Anxiety Disorders, 15, 345-357.

American Psychiatric Association. (2000). Diagnostic and statistical manual of mental

disorders (4th ed., text revision). Washington, DC: Author.

Arbuckle, J. L. (2006). Amos (Version 7.0) [Computer Program], Chicago: SPSS.

Asmundson, G. J. G., Coons, M. J., Taylor, S., & Katz, J. (2002). PTSD and the

experience of pain: Research and clinical implications of shared vulnerability and

mutual maintenance models. Canadian Journal of Psychiatry, 47, 930-937.

Asmundson, G. J. G., Frombach, I., McQuaid, J., Pedrelli, P., Lenox, R., & Stein, M. B.

(2000). Dimensionality of posttraumatic stress symptoms: A confirmatory factor

analysis of DSM-IV symptom clusters and other symptom models. Behaviour

Research and Therapy, 38, 203-214.

Asmundson, G. J. G., & Stapleton, J. A. (2008). Associations between dimensions of

anxiety sensitivity and PTSD symptom clusters in active-duty police officers.

Cognitive Behaviour Therapy, 37, 66-75.

Bagby, R. M., Ryder, A. G., Schuller, D. R., & Marshall, M. B. (2004). The Hamilton

Depression Rating Scale: Has the gold standard become a lead weight? American

Journal of Psychiatry, 161, 2163-2177.

Barlow, D. H., Allen, L. B., & Choate, M. L. (2004). Toward a unified treatment for

emotional disorders. Behavior Therapy, 35, 205-230. 45

Baschnagel, J. S., O’Connor, R. M., Colder, C. R., & Hawk, L. W., Jr. (2005). Factor

structure of posttraumatic stress among western New York undergraduates

following the September 11th terrorist attack on the World Trade Center. Journal

of Traumatic Stress, 18, 677-684.

Beck, A. T., & Steer, R. A. (1990). Manual for the Beck Anxiety Inventory. San Antonio,

TX: Psychological Corporation.

Beck, A. T., Steer, R. A., & Carbin, M. G. (1988). Psychometric properties of the Beck

Depression Inventory: Twenty-five years of evaluation. Clinical Psychology

Review, 8, 77-100.

Beck, A. T., Ward, C. H., Mendelsohn, M., Mock, J., & Erbaugh, J. (1961). An inventory

for measuring depression. Archives of General Psychiatry, 4, 561-571.

Blanchard, E. B., Buckley, T. C., Hickling, E. J., & Taylor, A. E. (1998). Posttraumatic

stress disorder and comorbid major depression: Is the correlation an illusion?

Journal of Anxiety Disorders, 12, 21-37.

Bleich, A., Koslowsky, M., Dolev, A., & Lerer, B. (1997). Post-traumatic stress disorder

and depression: An analysis of comorbidity. British Journal of Psychiatry, 170,

479-482.

Bramsen, I., Dirkzwager, A. J. E., & van der Ploeg, H. M. (2000). Predeployment

personality traits and exposure to trauma as predictors of posttraumatic stress

symptoms: A prospective study of former peacekeepers. American Journal of

Psychiatry, 157, 1115-1119. 46

Breslau, N., Davis, G. C., Andreski, P., & Peterson, E. (1991). Traumatic events and

posttraumatic stress disorder in an urban population of young adults. Archives of

General Psychiatry, 48, 216-222.

Brown, T. A. (2007). Temporal course and structural relationships among dimensions of

temperament and DSM-IV anxiety and mood disorder constructs. Journal of

Abnormal Psychology, 116, 313-328.

Brown, T. A., Chorpita, B. F., & Barlow, D. H. (1998). Structural relationships among

dimensions of the DSM-IV anxiety and mood disorders and dimensions of

negative affect, positive affect, and autonomic arousal. Journal of Abnormal

Psychology, 107, 179-192.

Brown, T. A., & McNiff, J. (2009). Specificity of autonomic arousal to DSM-IV panic

disorder and posttraumatic stress disorder. Behaviour Research and Therapy, 47,

487-493.

Buckley, T. C., Blanchard, E. B., & Hickling, E. J. (1998). A confirmatory factor analysis

of posttraumatic stress symptoms. Behaviour Research and Therapy, 36, 1091-

1099.

Clark, L. A., & Watson, D. (1991). Tripartite model of anxiety and depression:

Psychometric evidence and taxonomic implications. Journal of Abnormal

Psychology, 100, 316-336.

Clark, L. A., Watson, D., & Mineka, S. (1994). Temperament, personality, and the mood

and anxiety disorders. Journal of Abnormal Psychology, 103, 103-116. 47

Cordova, M. J., Studts, J. L., Hann, D. M., Jacobsen, P. B., & Andrykowski, M. A.

(2000). Symptom structure of PTSD following breast cancer. Journal of

Traumatic Stress, 13, 301-319.

Cox, B. J., Clara, I. P., & Enns, M. W. (2002). Posttraumatic stress disorder and the

structure of common mental disorders. Depression and Anxiety, 15, 168-171.

Dimidjian, S., Hollon, S. D., Dobson, K. S., Schmaling, K. B., Kohlenberg, R. J., Addis,

M. E., et al. (2006). Randomized trial of behavioral activation, cognitive therapy,

and antidepressant medication in the acute treatment of adults with major

depression. Journal of Consulting and Clinical Psychology, 74, 658-670.

Fauerbach, J. A., Lawrence, J. W., Schmidt, C. W., Jr., Munster, A. M., & Costa, P. T.,

Jr. (2000). Personality predictors of injury-related posttraumatic stress disorder.

Journal of Nervous and Mental Disease, 188, 510-517.

Feldner, M. T., Lewis, S. F., Leen-Feldner, E. W., Schnurr, P. P., & Zvolensky, M. J.

(2006). Anxiety sensitivity as a moderator of the relation between trauma

exposure frequency and posttraumatic stress symptomatology. Journal of

Cognitive Psychotherapy: An International Quarterly, 20, 201-213.

First, M. B., Spitzer, R. L., Gibbon, M., & Williams, J. B.W. (2001). Structured Clinical

Interview for DSM-IV-TR Axis I Disorders, Research Version, Patient Edition

With Psychotic Screen (SCID-I/P w/ PSY SCREEN). New York: Biometrics

Research, New York State Psychiatric Institute.

Foa, E. B., Riggs, D. S., Dancu, C. V., & Rothbaum, B. O. (1993). Reliability and

validity of a brief instrument for assessing posttraumatic stress disorder. Journal

of Traumatic Stress, 6, 459-473. 48

Foa, E. B., & Tolin, D. F. (2000). Comparison of the PTSD Symptom Scale – Interview

Version and the Clinician-Administered PTSD Scale. Journal of Traumatic

Stress, 13, 181-191.

Gamez, W., Watson, D., & Doebbeling, B. N. (2007). Abnormal personality and the

mood and anxiety disorders: Implications for structural models of anxiety and

depression. Journal of Anxiety Disorders, 21, 526-539.

Grant, D. M., Beck, J. G., Marques, L., Palyo, S. A., & Clapp, J. D. (2008). The structure

of distress following trauma: Posttraumatic stress disorder, major depressive

disorder, and generalized anxiety disorder. Journal of Abnormal Psychology, 117,

662-672.

Green, B. L., Krupnick, J. L., Chung, J., Siddique, J., Krause, E. D., Revicki, D., et al.

(2006). Impact of PTSD comorbidity on one-year outcomes in a depression trial.

Journal of Clinical Psychology, 62, 815-835.

Hamilton, M. (1960). A rating scale for depression. Journal of Neurology, Neurosurgery,

and Psychiatry, 23, 56-62.

Hu, L., & Bentler, P. M. (1998). Fit indices in covariance structure modeling: Sensitivity

to underparameterized model misspecification. Psychological Methods, 3, 424-

453.

Hughes, A. A., Heimberg, R. G., Coles, M. E., Gibb, B. E., Liebowitz, M. R., &

Schneier, F. R. (2006). Relations of the factors of the tripartite model of anxiety

and depression to types of social anxiety. Behaviour Research and Therapy, 44,

1629-1641. 49

John, O. P., Donahue, E. M., & Kentle, R. L. (1991). The Big Five Inventory--Versions

4a and 54. Berkeley: University of California, Berkeley, Institute of Personality

and Social Research.

John, O. P., & Srivastava, S. (1999). The Big Five trait taxonomy: History, measurement,

and theoretical perspectives. In L. A. Pervin & O. P. John (Eds.), Handbook of

personality: Theory and research (2nd ed.) (pp. 102-138). New York: Guilford

Press.

Kessler, R. C., Chiu, W. T., Demler, O., & Walters, E. E. (2005). Prevalence, severity,

and comorbidity of 12-month DSM-IV disorders in the National Comorbidity

Survey Replication. Archives of General Psychiatry, 62, 617-627.

Kessler, R. C., Sonnega, A., Bromet, E., Hughes, M., & Nelson, C. B. (1995).

Posttraumatic stress disorder in the National Comorbidity Survey. Archives of

General Psychiatry, 52, 1048-1060.

King, D. W., Leskin, G. A., King, L. A., & Weathers, F. W. (1998). Confirmatory factor

analysis of the Clinician-Administered PTSD Scale: Evidence for the

dimensionality of posttraumatic stress disorder. Psychological Assessment, 10,

90-96.

Kline, R. B. (2005). Principles and practice of structural equation modeling (2nd ed.).

New York: Guilford Press.

Krause, E. D., Kaltman, S., Goodman, L. A., & Dutton, M. A. (2007). Longitudinal

factor structure of posttraumatic stress symptoms related to intimate partner

violence. Psychological Assessment, 19, 165-175. 50

Lang, A. J., Kennedy, C. M., & Stein, M. B. (2002). Anxiety sensitivity and PTSD

among female victims of intimate partner violence. Depression and Anxiety, 16,

77-83.

Lilienfeld, S. O., Waldman, I. D., & Israel, A. C. (1994). A critical examination of the

use of the term and concept of comorbidity in psychopathology research. Clinical

Psychology: Science and Practice, 1, 71-83.

McNally, R. J. (1999). Theoretical approaches to the fear of anxiety. In S. Taylor (Ed.),

Anxiety sensitivity: Theory, research, and treatment of the fear of anxiety (pp. 3-

16). Mahwah, NJ: Lawrence Erlbaum Associates.

Meng, X.-L., Rosenthal, R., & Rubin, D. B. (1992). Comparing correlated correlation

coefficients. Psychological Bulletin, 111, 172-175.

Mineka, S., Watson, D., & Clark, L. A. (1998). Comorbidity of anxiety and unipolar

mood disorders. Annual Review of Psychology, 49, 377-412.

Momartin, S., Silove, D., Manicavasagar, V., & Steel, Z. (2004). Comorbidity of PTSD

and depression: Associations with trauma exposure, symptom severity and

functional impairment in Bosnian refugees resettled in Australia. Journal of

Affective Disorders, 80, 231-238.

Nixon, R. D. V., Resick, P. A., & Nishith, P. (2004). An exploration of comorbid

depression among female victims of intimate partner violence with posttraumatic

stress disorder. Journal of Affective Disorders, 82, 315-320.

O’Donnell, M. L., Creamer, M., & Pattison, P. (2004). Posttraumatic stress disorder and

depression following trauma: Understanding comorbidity. American Journal of

Psychiatry, 161, 1390-1396. 51

Oquendo, M., Brent, D. A., Birmaher, B., Greenhill, L., Kolko, D., Stanley, B., et al.

(2005). Posttraumatic stress disorder comorbid with major depression: Factors

mediating the association with suicidal behavior. American Journal of Psychiatry,

162, 560-566.

O’Toole, B. I., Marshall, R. P., Schureck, R. J., & Dobson, M. (1998). Risk factors for

posttraumatic stress disorder in Australian Vietnam veterans. Australian and New

Zealand Journal of Psychiatry, 32, 21-31.

Palmieri, P. A., Weathers, F. W., Difede, J., & King, D. W. (2007). Confirmatory factor

analysis of the PTSD Checklist and the Clinician-Administered PTSD Scale in

disaster workers exposed to the World Trade Center ground zero. Journal of

Abnormal Psychology, 116, 329-341.

Raykov, T., & Marcoulides, G. A. (2006). A first course in structural equation modeling

(2nd ed.). Mahwah, NJ: Lawrence Erlbaum Associates.

Rehm, L. P., & O’Hara, M. W. (1985). Item characteristics of the Hamilton Rating Scale

for Depression. Journal of Psychiatric Research, 19, 31-41.

Reiss, S., Peterson, R. A., Gursky, D. M., & McNally, R. J. (1986). Anxiety sensitivity,

anxiety frequency and the prediction of fearfulness. Behaviour Research and

Therapy, 24, 1-8.

Resick, P. (in press). Posttraumatic stress disorder: Anxiety or traumatic-stress disorder?

Journal of Traumatic Stress.

Rodriguez, B. F., Bruce, S. E., Pagano, M. E., Spencer, M. A., & Keller, M. B. (2004).

Factor structure and stability of the Anxiety Sensitivity Index in a longitudinal

study of anxiety disorder patients. Behaviour Research and Therapy, 42, 79-91. 52

Rosen, G. M., & Lilienfeld, S. O. (2008). Posttraumatic stress disorder: An empirical

evaluation of core assumptions. Clinical Psychology Review, 28, 837-868.

Shalev, A. Y., Freedman, S., Peri, T., Brandes, D., Sahar, T., Orr, S. P., et al. (1998).

Prospective study of posttraumatic stress disorder and depression following

trauma. American Journal of Psychiatry, 155, 630-637.

Simms, L. J., Watson, D., & Doebbeling, B. N. (2002). Confirmatory factor analyses of

posttraumatic stress symptoms in deployed and nondeployed veterans of the Gulf

War. Journal of Abnormal Psychology, 111, 637-647.

Slade, T., & Watson, D. (2006). The structure of common DSM-IV and ICD-10 mental

disorders in the Australian general population. Psychological Medicine, 36, 1593-

1600.

Spitzer, R. L., First, M. B., & Wakefield, J. C. (2007). Saving PTSD from itself in DSM-

V. Journal of Anxiety Disorders, 21, 233-241.

Tabachnick, B. G., & Fidell, L. S. (1996). Using multivariate statistics (3rd ed.). New

York: HarperCollins.

Taylor, S. (1999). Anxiety sensitivity: Theory, research, and treatment of the fear of

anxiety. Mahwah, NJ: Lawrence Erlbaum Associates.

Taylor, S., Koch, W. J., & McNally, R. J. (1992). How does anxiety sensitivity vary

across the anxiety disorders? Journal of Anxiety Disorders, 6, 249-259.

Taylor, S., Koch, W. J., Woody, S., & McLean, P. (1996). Anxiety sensitivity and

depression: How are they related? Journal of Abnormal Psychology, 105, 474-

479.

Wagner, A. W., Zatzick, D. F., Ghesquiere, A., & Jurkovich, G. J. (2007). Behavioral 53

activation as an early intervention for posttraumatic stress disorder and depression

among physically injured trauma survivors. Cognitive and Behavioral Practice,

14, 341-349.

Watson, D. (2005). Rethinking the mood and anxiety disorders: A quantitative

hierarchical model for DSM-V. Journal of Abnormal Psychology, 114, 522-536.

Watson, D., Clark, L. A., & Tellegen, A. (1988). Development and validation of brief

measures of positive and negative affect: The PANAS scales. Journal of

Personality and Social Psychology, 54, 1063-1070.

Watson, D., Clark, L. A., Weber, K., Assenheimer, J. S., Strauss, M. E., & McCormick,

R. A. (1995). Testing a tripartite model: II. Exploring the symptom structure of

anxiety and depression in student, adult, and patient samples. Journal of

Abnormal Psychology, 104, 15-25.

Watson, D., Gamez, W., & Simms, L. J. (2005). Basic dimensions of temperament and

their relation to anxiety and depression: A symptom-based perspective. Journal of

Research in Personality, 39, 46-66.

Watson, D., Weber, K., Assenheimer, J. S., Clark, L. A., Strauss, M. E., & McCormick,

R. A. (1995). Testing a tripartite model: I. Evaluating the convergent and

discriminant validity of anxiety and depression symptom scales. Journal of

Abnormal Psychology, 104, 3-14.

Zanarini, M. C., Skodol, A. E., Bender, D., Dolan, R., Sanislow, C., Schaefer, E., et al.

(2000). The Collaborative Longitudinal Personality Disorders Study: Reliability

of axis I and II diagnoses. Journal of Personality Disorders, 14, 291-299.

Zinbarg, R. E., & Barlow, D. H. (1996). Structure of anxiety and the anxiety disorders: A 54

hierarchical model. Journal of Abnormal Psychology, 105, 181-193.

Zinbarg, R. E., Barlow, D. H., & Brown, T. A. (1997). Hierarchical structure and general

factor saturation of the Anxiety Sensitivity Index: Evidence and implications.

Psychological Assessment, 9, 277-284.

Zinbarg, R. E., Brown, T. A., Barlow, D. H., & Rapee, R. M. (2001). Anxiety sensitivity,

panic, and depressed mood: A reanalysis teasing apart the contributions of the two

levels in the hierarchical structure of the Anxiety Sensitivity Index. Journal of

Abnormal Psychology, 110, 372-377.