SWAN-DE-SB Validation of a Self-Report Version of the German Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Scale
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SWAN-DE-SB Validation of a Self-Report Version of the German Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Scale (SWAN-DE-SB) Friederike Blume 1,2 *, Jan Kühnhausen 1,2,3 *, Lilly Buhr 1, Rieke Köpke 1, Andreas J. Fallgatter 2,4, Caterina Gawrilow 1,2,3 1 Department Psychology, School Psychology, University of Tübingen, Schleichstr. 4, 72076 Tübingen, Germany 2 LEAD Graduate School & Research Network, University of Tübingen, Walter-Simon-Str. 12, 72072 Tübingen, Germany 3 Center for Individual Development and Adaptive Education of Children at Risk (IDeA), DIPF | Leibniz Institute for Research and Information in Education, Rostocker Straße 6, 60323 Frankfurt am Main, Germany 4 Department of Psychiatry and Psychotherapy, University Hospital Tübingen, Calwer Str. 14, 72076 Tübingen * equal contribution Friederike Blume now works at the DIPF | Leibniz Institute for Research and Information in Education, Rostocker Straße 6, 60323 Frankfurt am Main, Germany and is additionally affiliated with the Center for Individual Development and Adaptive Education of Children at Risk (IDeA). Jan Kühnhausen now works at the Department of Child and Adolescent Psychiatry, University Hospital Tübingen, Osianderstr. 14-16, 72076 Tübingen Corresponding author: Dr. Friederike Blume, DIPF | Leibniz Institute for Research and Information in Education, Rostocker Straße 6, 60323 Frankfurt am Main, Germany. E-mail: [email protected] SWAN-DE-SB Note. This preprint is based on data from 405 adults of whom 17 reported to have received a diagnosis of attention-deficit/hyperactivity disorder (ADHD) earlier, and 14 indicated a current ADHD diagnosis. However, diagnoses were not verified by a clinician through means of a structured diagnostic process. With the help Lydia Weber and Thomas Ethofer (both Department of Psychiatry and Psychotherapy, University Hospital Tübingen), the study therefore currently recruits an additional clinical sample of patients whose ADHD diagnosis is verified through a qualified clinician. Implications drawn in relation to patients should therefore be considered with caution in the meantime. SWAN-DE-SB Abstract While the excellent psychometric quality of the German third-party report version of the Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Scale (SWAN-DE) for school-aged children was recently demonstrated, a self-report version employable with adults was not available so far. The present study therefore aimed at developing and validating the SWAN-DE-SB, a self-report version of the SWAN- DE. Based on data obtained from 405 adults, 14 (3.5%) of them with a current ADHD diagnosis, normality, internal consistency, as well as factorial and convergent validity were examined. The SWAN-DE-SB yielded normally distributed scores, high internal consistency, and factorial validity. The scale was shown to discriminate between participants with and without ADHD and to significantly correlate with commonly employed clinical ADHD scales. With the SWAN-DE-SB, we introduce a self-report measure assessing both strengths and weaknesses of ADHD symptoms and normal behavior and demonstrated its excellent psychometric properties. Key words: SWAN scale, Attention-Deficit/Hyperactivity Disorder, self-regulation, self-report SWAN-DE-SB 1 Adult attention-deficit/hyperactivity disorder (ADHD; American Psychiatric Association, 2013) is characterized by intense symptoms of either inattention (e.g., difficulty sustaining attention at work, during tasks or activities), hyperactivity-impulsivity (e.g., motor overactivity such as having difficulties remaining seated although social conventions require it, or inner restlessness; interrupting or intruding on others by butting into conversations), or both. These core symptoms were shown to implicate impaired academic (e.g., fewer high school and university degrees), occupational (e.g., lower overall income), as well as social functioning (e.g., fewer friends, higher divorce rates; Frazier, Youngstrom, Glutting, & Watkins, 2007; Fredriksen et al., 2014; Friedman et al., 2003; Mannuzza, Klein, Bessler, Malloy, & Hynes, 1997). Classified as a neurodevelopmental disorder, symptoms are expected to occur in childhood already, while approximately 2.5% of adults are diagnosed with ADHD (Simon, Czobor, Bálint, Mészáros, & Bitter, 2009). Empirical evidence, however, clearly suggests that not only individuals diagnosed with ADHD, but all people experiences ADHD symptoms to a certain degree from time to time. This supports the assumption that ADHD comprises a continuum reaching from no or very low to very intense, and thus clinically significant symptomatology rather than a category (i.e., ADHD as opposed to no ADHD; Frazier, Youngstrom, & Naugle, 2007; Haslam et al., 2006; Levy, Hay, McStephen, Wood, & Waldman, 1997; Marcus & Barry, 2011; Salum et al., 2014). Relatively asymptomatic individuals can thus be assumed to experience intensities representing the positive extreme (i.e., functionality), while patients with ADHD can thus be assumed to experience symptom intensities representing the negative extreme (i.e., dysfunctionality) of a continuum continuously distributed across the general population. Nevertheless, common clinical ADHD rating scales usually depict a deficit-oriented view, thereby solely focusing on individuals’ weaknesses while ignoring strengths, hence artificially truncating the full range of behaviors (Swanson et al., 2012). This approach could result in major difficulties, especially when assessing ADHD symptoms in non-clinical samples (cf. Schulz-Zhecheva et al., 2017; Swanson et al., 2012). First, as the majority of the general population presents with no or only rarely occurring ADHD symptoms and only few individuals anchor at the negative extreme of such scales, any such clinical scale typically produces a skewed distribution. This is problematic as it might result in an overestimation of the prevalence of ADHD when cut-off scores (i.e., scores that separate those with from those without an ADHD diagnosis) SWAN-DE-SB 2 are derived on the basis of data assumed to be normally distributed. Additionally, such distributions result in severe methodological ramifications in studies depicting ADHD as a continuous trait in the general population as, by overlooking meaningful variance at the positive end of the distribution, statistical power and validity would be substantially reduced. Second, when solely focusing on individuals’ deficits, strengths allowing to compensate for one’s weaknesses (e.g., to be organized although one experiences difficulties in staying focused when working on a task) are overlooked, which results in low construct validity of such scales, as only part of the construct is captured. Additionally, strengths cannot directly be reinforced in psychotherapeutic settings, which would be important in terms of improving the patients’ self-esteem. Consequently, to face these challenges, scales assessing both weaknesses (i.e., dysfunctionality) and strengths (i.e., functionality) of ADHD symptoms are urgently required. In an attempt to overcome these shortcomings, Swanson and colleagues (2012) introduced the Strengths and Weaknesses of ADHD-Symptoms and Normal-Behavior (SWAN) Scale assessing symptoms of school-aged children’s inattention and hyperactivity-impulsivity in the form of a third-party report. This scale is based on the symptom criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; American Psychiatric Association [APA], 2000, also in accordance with DSM-5, APA, 2013) and comprises 18 items. As they are designed to assess school-aged children’s symptomatology, the items’ wording addresses school and play situations as well as children’s behavior at home. All items are worded positively instead of negatively as clinical scales usually are (e.g., “Remembers daily activities” instead of “Is often forgetful in daily activities”). Accordingly, a 7-point scale anchoring the negative (i.e., “far below average”) and the positive (i.e., “far above average”) end of the dimension allowed to well differentiate between children’s actual strengths and weaknesses. This original SWAN scale comprised the first scale assessing ADHD symptoms in a truly dimensional way. Alongside its translations to Spanish, French, Chinese, and German, it was shown to have excellent psychometric properties such as to result in normally distributed data in the general population, to have high internal consistency and adequate retest reliability, a consistent factor structure, and excellent convergent validity as indicated by high correlations with existing diagnostic instruments (Arnett et al., 2013; Hay, Bennett, Levy, Sergeant, & Swanson, 2007; Lakes, Swanson, & Riggs, 2012; Polderman et al., 2007; Schulz-Zhecheva et al., 2017; SWAN-DE-SB 3 Swanson et al., 2012). Additionally, its sensitivity and specificity in distinguishing school-aged children with and without ADHD as well as school-aged children with ADHD and other mental disorders were demonstrated (Chan, Lai, Luk, Hung, & Leung, 2014; Lai et al., 2013; Robaey, Amre, Schachar, & Simard, 2007; Schulz-Zhecheva et al., 2017). Nevertheless, neither the original SWAN scale nor any of its translations can be used with adults. This is because first, the items’ wording relates to schoolchildren’s activities and environments. Second, while third-party reports interviewing parents and teachers are commonly employed with younger children, self-reports become increasingly important when assessing