The Impact of Autism Spectrum Disorder Traits on the Treatment Outcome of Patients with Obsessive Compulsive Spectrum Disorder

The impact of autism spectrum disorder traits on the treatment outcome of patients with obsessive compulsive spectrum disorder

Master Thesis: Health Psychology, specialisation: Clinical Psychology University of Amsterdam, July 20th, 2016 Research performed at the Academic Medical Centre in Amsterdam, Department of Psychiatry

Student Supervisors

Vrouwkjen Frederieke Joanne UvA: dr. L. Boyette Glas AMC: drs. M. van der Pol (6065244)

Index

Title Page………………………………………………………………………………… 1

Index……………………………………………………………………………………... 2

Abstract…………………………………………………………………………………... 3

Introduction……………………………………………………………………………… 3

Methods………………………………………………………………………………….. 7

Results……………………………………………………………………………………. 11

Discussion………………………………………………………………………………… 15

References………………………………………………………………………………... 20

Appendix 1 – Autism-spectrum Quotient (in Dutch)……… ……………………………. 25

Appendix 2 – Yale-Brown Obsessive Compulsive Scale (in Dutch)……………………. 28

Abstract

Despite a high comorbidity between obsessive compulsive disorder (OCD) and autism spectrum disorder (ASD), the relation between both disorders is not yet fully understood.

There is some evidence that ASD traits could have an negative impact on a regular OCD treatment, however limited research has focused on the treatment of OCD in people with ASD traits. Therefore, this study focused on whether people with more ASD traits would (A) profit less from cognitive behavioural therapy (CBT) for obsessive compulsive spectrum disorder

(OCSD), (B) have more severe OCSD symptoms before the treatment and (C) a higher dropout rate. 67 subjects followed a 16-week CBT for OCSD, in which treatment efficacy and

ASD traits were assessed. Results showed no impact from ASD traits on treatment efficacy,

OCSD severity before treatment and the dropout rate. From this it can be concluded that slightly elevated ASD-traits made no impact on the treatment outcome. However, a limitation in this study was that there was little variation in ASD traits between subjects. Future research can be directed at clinical ASD and components of CBT that are most effective for people with ASD and comorbid OCSD.

Introduction

Obsessive compulsive disorder is an anxiety disorder within the obsessive compulsive spectrum. The obsessive compulsive spectrum (OCSD) contains a range of disorders, such as

OCD, trichotillomania and body dysmorphic disorder (BDD). Obsessive compulsive symptoms are persistent thoughts, urges or images that are experienced as intrusive.

Symptoms also include repetitive behaviours or mental acts which are performed in response to an obsession or according to rules that must be applied rigidly (American Psychiatric

Association, 2013). Obsessive compulsive behaviour can also be characterized by preoccupations and attempts to stop the compulsions or obsessions. The nosology of OCD has

been subject of recent debate, since the phenomenology of OCD has many different features and in some cases non-specific symptoms (Ivarsson & Melin, 2008). Certain phenomenology and neurophysiology of OCSD is associated in the literature with autism spectrum disorder

(ASD), which will be explained further on.

Autism is a neurodevelopmental disorder which often first appears in early childhood.

General characteristics of ASD are persistent deficits in social communication and interaction in addition to restricted and repetitive patterns of behaviour, interests and activities (American

Psychiatric Association, 2000). The prevalence of ASD in adults and children is estimated at

1% (Brugha et al., 2011, Kan et al., 2013). Recent literature shows that people with ASD report a lower level of quality of life than their peers without ASD (van Heijst & Geurts,

2015; de Vries & Geurts, 2015). Furthermore, people with ASD have a higher risk on developing comorbid psychiatric disorders (Bradley et al., 2004; Hofvander et al., 2009). For instance, anxiety disorders appear to be more common among people with ASD than people without ASD (Brereton et al., 2006; Gadke, 2016; Reaven, 2011). Children with ASD have a higher risk on developing anxiety related symptoms than children without ASD (Brereton et al., 2006; Gillot et al., 2001). Specifically OCD is relatively common in ASD, with a comorbidity rate estimated at 10% (Neil & Sturmey, 2014). ASD traits are prevalent in OCD as well and there are reasons to assume ASD traits are associated with OCD severity (Bejerot,

2001; Ivarsson & Melin, 2008; Stewart et al., 2016).

Literature suggests there are several reasons to assume a link between OCSD and ASD.

Behaviour that is typical in ASD is often seen in obsessive compulsive spectrum disorders

(OCSD) as well, such as rigidity and repetitive behaviour. Repetitive behaviour is a non- specific symptom, seen in many different psychiatric disorders (Lewis & Bodfish, 1998), including ASD and OCD (Ruzzano et al., 2015). Also, social competence deficits are not only common in ASD, but evidence suggests OCD and BDD are also associated with slight deficits

in social competences, such as shyness and social anxiety (Chasson et al., 2011). There are indications that people with ASD and people with BDD have difficulties with emotion recognition (Chasson et al., 2011). Also ritualistic behaviour, such as counting and following a rigid routine, are common in both ASD and OCSD (Allen et al., 2003). In addition to this phenomenological overlap, there is certain related pathophysiology between ASD and OCD.

For example, a cluster of diseases, which include OCD and ASD, are associated with a certain variant of the serotonin transporter gene (Ozaki et al., 2003).

Overlap in behaviour and neurophysiology generates growing attention for the linkage between OCSD and ASD, but the course of treatment for ASD traits in OCSD remains understudied. To date, most research in this area focuses on children or adolescents and on anxiety disorders in general. Studies on the treatment of anxiety disorders show that cognitive behavioural therapy (CBT) is more effective than treatment as usual (TAU) for people with

ASD (Storch et al., 2015; Sukhodolsky et al., 2013). Meta-analysis shows CBT has moderate treatment gains for people with ASD and an anxiety disorder (Ung et al., 2015). The same study shows that (young) people with ASD and a comorbid anxiety disorder can profit from

CBT. However, there are also indications that people with more ASD-traits profit less from

CBT for anxiety disorders than people with less ASD-traits. Van Steensel et al. (2015) show for example that children with ASD and a comorbid anxiety disorder have more anxiety symptoms after CBT compared to children with only an anxiety disorder. People with ASD can profit (moderately) from CBT, but it is unclear whether CBT is less effective for people with more ASD traits.

Mito et al. (2014) did research similar to the present study and compared people with more

ASD-traits and OCD to people with less ASD-traits and OCD. They found that higher levels of ASD traits did not correlate with a lower treatment outcome. However, their CBT- treatment lasted 47-weeks, and in regular Dutch treatment settings an OCD (group) treatment

is less extensive. It cannot be ruled out that shorter treatments will show less improvement in people with ASD compared to people with pure OCD. It is therefore hypothesized in this study that a standard OCSD-treatment could be less effective for patients with more ASD traits. For example, next to persistent deficits in communication and forming social relationships, people with ASD often have difficulties integrating sensory information (Baker et al., 2008). People with ASD often thrive in highly structured settings (Krasny et al., 2003;

Hum et al., 2014) and it is possible that a regular (group-) treatment setting does not offer enough structure or offers information in a relatively high pace. It is also possible that symptomatic overlap between both disorders causes difficulties in the treatment, since repetitive and ritualistic behaviour can be helpful for people with ASD whereas for people with OCSD this behaviour it is often dysfunctional. Also, social deficits can be a limiting factor, especially in a group treatment.

Because of these traits it is possible that people with a more ASD-traits can experience difficulties in a regular treatment program for OC(S)D and profit less than people with less

ASD-traits. If CBT would prove to be less effective in people with OCSD and comorbid

ASD, this could be a reason to study different treatment components and adjust them for this specific sub-population. Having a less effective treatment for people with ASD would indicate that there might be components in the treatment that could be adjusted, for it to be more profitable for people with ASD and OCD.

The main objective of our research is therefore to evaluate the impact of ASD traits on the treatment outcome of patients with OCSD. We have preferred this objective above the alternative of investigating OCSD symptoms in the context of ASD, for clinical reasons mainly. It seems clinically more relevant to study ASD traits in the context of OCSD than, reversely, OCSD in the context of ASD, since we expect there will be more variation in ASD traits in OSCD than OCSD symptoms in ASD. The aim of this study is to examine (A)

whether people with higher levels of ASD traits have a lower treatment outcome of cognitive behavioural therapy (CBT) for OCSD than people with lower levels of ASD traits. In addition, (B) it is examined whether a higher level of ASD traits lead to a higher dropout rate during treatment. The effect of the treatment can also be influenced by the severity of the symptoms before the start of the treatment. Therefore, (C) it is examined whether people with a higher level of ASD traits suffer from more severe OCD symptoms before the treatment.

Eventually, understanding the role of ASD in treating OCSD may help develop better intervention strategies.

Methods

Participants

Ninety subjects were recruited from outpatients eligible for, or who had followed, CBT group therapy for OCD or BDD at the Academic Medical Centre (Amsterdam). There were two manners through which subjects were recruited. The first recruitment took place between

August 2015 and June 2016. In this period, the Autism-spectrum Quotient (AQ), a questionnaire, was added to the standard intake and treatment procedure. All subjects primarily met DSM-IV criteria for OCD or BDD. Subjects with BDD were included as well, as according to DSM-V criteria BDD belongs to the cluster of the obsessive-compulsive spectrum (American Psychiatric Association, 2013). Also, OCD and BDD are treated by a similar approach in the Academic Medical Centre, within the same division that is specialized in treating compulsive behaviour. There was no other major disorder on axis I or II. During assessment all patients were seen by a team of experts in anxiety and OCSD, consisting of a psychiatrist, psychologist and a behavioural expert. A semi structured interview, the MINI

Plus, was administered to ascertain all patients met primarily criteria for the diagnosis of OCD or BDD.

The second manner for recruiting subjects was aimed at subjects who were patients in the

Academic Medical Centre before August 2015. Subjects who were patients between January

2013 and August 2015, who had given a written consent in which they allowed to be approached for scientific research, were also asked to participate in this study. Requirements were that their file contained their Y-BOCS scores and that they had followed a BDD or OCD treatment (CBT). They completed the AQ by e-mail or telephone in the period between April

2016 and June 2016.

Measurements

The Autism-spectrum quotient (AQ) was developed as a brief self-report questionnaire to measure symptoms of ASD (Baron-Cohen et al., 2001) and contains 50 items (see appendix

1). The AQ measures symptoms on 5 domains, namely: communication (1), social skills (2), attention switching (3), imagination (4) and attention to detail (5). For this study we used the

Dutch version which is the first choice screening instrument for ASD in the Netherlands for adults (Hoekstra et al., 2008; Kan, 2013). The AQ was administered at the start of the treatment or retrospective via phone or e-mail. Symptom ratings on the AQ were made by assessors and were blind to therapists and patients. The (Dutch version of the) AQ was found to have a test-retest reliability of r.78 (Hoekstra et al., 2008), so test scores were expected to remain stable over time.

Primary efficacy of the treatment was assessed by change on the Yale-Brown Obsessive-

Compulsive Scale (Y-BOCS; Goodman et al., 1989a; Goodman et al., 1989b) and the Yale-

Brown obsessive-compulsive scale for BDD (BDD Y-BOCS; Phillips et al., 1997). The

(BDD-)Y-BOCS was developed to measure obsessive compulsive symptoms. This was done by measuring, for example, the time spent on compulsive thoughts or behaviour, the amount of anxiety the obsessive compulsive behaviour gives the patient and how often a patient tries

to resist it (see appendix 2). (BDD-)Y-BOCS scores were obtained by trained psychologists before, during and after treatment.

Treatment

Subjects took part in a regular CBT program for OCD or BDD at the psychiatry department of the Academic Medical Centre, which has a division specialized in the treatment of compulsive behaviour. Treatment consists of a combination of cognitive therapy and exposure therapy with response prevention (ERP) and lasted 16 weeks. OCD group therapy has a 1 day/week program and consists of 90 minutes ERP, 90 minutes cognitive therapy and 75 minutes discussing homework and treatment progress. BDD group therapy is a 2 days/week program and consists apart from the above, of 90 minutes psychomotor therapy and 90 minutes drama therapy. Treatment was conducted by trained psychologists and behavioural therapists who had extensive experience in treating OCD and BDD in adults. Both groups had a maximum of 8 patients.

All subjects met individually with a therapist shortly before the start of their treatment in order to assess their eligibility and motivation. Standard efficacy measurements were done, including the Y-BOCS. The AQ was administered during this first appointment as well with subjects who were patients between August 2015 and June 2016. In the 6th and 12th week, and after the treatment, all subjects met again with their therapist to assess treatment efficacy.

Measurements done before and after the treatment were used in the analysis of this study.

However, if a subject dropped-out after week 6, their last Y-BOCS score was included as well.

Analysis

In this study, absolute scores on the Y-BOCS were used to measure treatment efficacy, in order to achieve more statistical power in comparison to the use of relative scores (Tu, 2016;

Vickers, 2001). The significance level for all analysis was set at p<0.05. Linear regression analyses was used to determine if (A) higher levels of ASD traits would lead to lower treatment outcome, measured by the variables treatment outcome (‘Y-BOCS before’ minus the ‘Y-BOCS after’) and the AQ-score. The data on both variables was normally distributed, there was homogeneity of variance and scores were independent, so the assumptions for the linear regression analyses were met. In order to gain more insight in the relation between

ASD traits and treatment outcome, correlations between the total and sub-scale score of the

AQ and the treatment outcome and pre-treatment Y-BOCS score were calculated. The subscales of the AQ were not normally distributed, therefore a Spearman’s correlation coefficient was calculated.

To examine if more ASD traits would lead to dropout more often a logistic regression was used (B), measured by the AQ-score and the variable ‘drop-out’. Assumptions of the logistic regression analyses were met, namely linearity, independence of errors and multicollinearity.

Linear regression analyses was used to determine if (C) higher levels of ASD traits would lead to more OCD symptoms before the treatment, measured by the variables ‘Y-BOCS before’ and the AQ-score. Model assumptions for the simple linear regression were met.

As part of explorative analyses, this study divided subjects into an ASD+ (AQ-score ≥ 27) and ASD- (AQ-score < 27) group. Woodbury-Smith et al. (2005) recommend a threshold score at 26 in a clinical sample for the AQ. With these two groups the three main hypothesis were repeated, using an independent t-test (A & C). However, basic assumptions for hypothesis A were not met since the scores on the difference between pre- and post-treatment

Y-BOCS in the ASD+ group were not normally distributed, so a Mann-Whitney Test was performed. Assumptions for the explorative logistic regression of hypotheses C were met. A

Fisher’s exact test was used for explorative hypothesis B since assumptions for a Chi-square test were not met. Also, whether OCD severity before the treatment could be predicted by

levels of ASD traits was explored with a logistic regression. A Y-BOCS score above 25 distinguishes a ‘moderately severe’ OCD from a ‘severe’ OCD. Therefore, an extra variable was created for people who had a Y-BOCS score above 25 and below 25. Assumptions for this model were met.

Results

From the 90 subjects, 23 cases were excluded for the main analysis due to incomplete patient files and therefore post-treatment Y-BOCS scores were not present. In these cases the reduction in the Y-BOCS could not be measured. For the third analysis (C), 8 subjects were excluded due to missing pre-treatment Y-BOCS scores. In the main analysis (A), 67 subjects were included. A post hoc power analysis revealed that the power is 0.06 for R²=.014, N=67 and p<.05. The age of the subjects varied between 19 and 76, with an average of 35,72 (12,0) years. 28 subjects were men and 39 subjects were women. OCD was diagnosed in 48 (71.6%) subjects, while BDD was diagnosed in 19 (28.4) subjects. Table 1 shows the average scores on the (BDD-)Y-BOCS, the AQ and the AQ subscales.

Table 1. (BDD-)Y-BOCS and the AQ scores.

M SD Min Max

Y-BOCS

Pre-treatment Y-BOCS 24.60 5.23 12 37

Post-treatment Y-BOCS 9.40 5.93 0 30

Difference pre and post Y-BOCS 15.21 6.78 -6 30

Pre-treatment BDD-YBOCS 31.05 5.16 17 39

Post-treatment BDD-YBOCS 17.11 7.85 6 34

Difference pre and post BDD-Y-BOCS 13.95 8.70 0 33

Total 19.16 7.07 6 39

Social Skill 3.54 2.45 0 10

Attention Switching 4.75 2.36 0 10

Attention to Details 5.00 2.07 1 10

Communication 2.70 2.03 0 7

Imagination 3.19 2.12 0 10

N= 67.

First, a simple linear regression was calculated to predict the effect of the treatment based on the level of ASD-traits. There was no difference between the treatment outcome scores on the

BDD-Y-BOCS and the Y-BOCS, t(65) = 0.632, p > .05. The results of the regression indicated that the amount of variance in the difference between pre and post treatment Y-

BOCS score explained by ASD-traits was not statistically significant (F(1,65)= 0.96, p>.05,

R²=0.01).

Additionally, subscale scores of the AQ were correlated with treatment outcome to explore if there was any relation between the subscales and the treatment outcome (Y-BOCS pre- treatment minus Y-BOCS post-treatment) on the Y-BOCS. Table 2 shows the results of the correlations between the total and subscale score of the AQ and reduction percentage on the

Y-BOCS and the pre-treatment score on the Y-BOCS. There was a significant difference between pre-treatment Y-BOCS and pre-treatment BDD-Y-BOCS scores, therefore results are shown separately, t(80) = -4.63, p < .01. No correlations were found to be significant.

Second, a logistic regression analyses was performed to test the effect of ASD traits on the likelihood that participants would stop the treatment prematurely. All subjects who stopped the treatment prematurely, after the first assessment and before the start of the treatment, were included in the analyses. Out of all subjects included in this analysis (N=90), 5 subjects

(5.6%) stopped before their treatment was finished. The logistic regression model was

Table 2. Spearman’s correlation coefficients with total and subscale scores of the AQ.

Total AQ Social Skill Attention Attention to Communication Imagination Switching Details

Difference in Y- -.230 -.190 -.111 -.049 -.215 -.073 BOCS (pre- and post-treatment)¹

Pre-treatment Y- .007 -.100 .031 .177 -.058 -.123 BOCS²

Pre-treatment .149 .123 .180 .079 .059 .003 BDD-Y-BOCS

¹N = 67. ²N = 56. 3N = 26.

insignificant, b=0.05 (0.06), χ ²(1)=0.73, p>.05. ASD traits were not a significant predictor for ending the treatment prematurely.

Third, a simple linear regression was calculated to predict the severity of OCD symptoms before treatment by ASD-traits. In this analyses, subjects who had no post-treatment Y-BOCS score reported in their patient file, or who were in treatment at the time, were included as well, thus 82 subjects were included. The results of the regression showed that the variance in pre-treatment Y-BOCS scores explained by the amount of ASD-traits was insignificant,

F(1,80)= 0.02, p>.05, R²= 0.00. People with higher levels of ASD traits did not have more severe symptoms before the treatment.

In addition to the main research questions, group characteristics of subjects who scored above the clinical threshold for screening on ASD were explored. Two groups were divided by a cut-off score of 26 on the AQ (Woodbury-Smith et al., 2005) into an ASD+ and ASD- group.

The ASD+ group consisted of 12 subjects and the ASD- group of 55 subjects. The average difference on the Y-BOCS (pre- minus post-treatment Y-BOCS score) did not differ significantly between the ASD- (Mdn = 15.00) and the ASD+ group (Mdn = 13.50), U =

302.50, z = -0.45, p > 0.05, r = -0.06. A Mann-Whitney U Test was performed, because the distribution in the ASD+ group was not-normal. Data on the distribution in the ASD+ group

(N = 12) showed that no subjects made an improvements on the Y-BOCS between 14 and 25 while the overall average improvement on the Y-BOCS was 14.85 (7.33). Also, being in the

ASD+ or ASD- group was not a predictor for the pre-treatment Y-BOCS score, b=-0.01

(0.05), χ ²(1)=0.04, p>.05. A Y-BOCS score above 25 distinguishes a ‘moderately severe’

OCD from a ‘severe’ OCD. Explorative analyses showed that having a severe OCD or a milder form of OCD (before the start of the treatment) was not predicted by the amount of

ASD traits, b=0.01 (0.08), χ ²(1)=0.01, p>.05.

Discussion

Limited research has focused on whether ASD traits have an impact on the effectiveness of treatment for OCSD. Therefore, this study examined whether the level of ASD traits have an impact on the efficacy of standard OCSD treatment. Results showed that the amount of ASD traits did not make a difference with respect to the results of standard OCSD treatment.

People with more ASD traits also did not suffer from more severe OCD symptoms nor did they drop out of the treatment more often. No relation was found between specific dimensions of the AQ and treatment outcome, nor did the severity of the OCSD predict the amount of

ASD traits. To sum up, contrary to what was expected based on literature on the relation between ASD and OCSD, this study found no evidence whatsoever that ASD traits had a negative impact on the treatment for OCSD.

It should be noted that people with comorbid ASD traits and OCSD showed only moderately elevated levels of ASD traits. Moreover, there appeared to be little variation in the number and severity of ASD traits. It can be concluded that people with moderately elevated ASD traits do not profit less from an OCSD treatment. It can, therefore, be concluded that CBT is effective for OCSD patients with moderately elevated ASD traits. This finding is in line with previous research on CBT treatment for anxiety disorders with comorbid ASD. There are some methodological and conceptual limitations in this study which may have influenced the current findings.

Methods

A limitation to the present study was low statistical power. Results in this study should therefore need to be interpreted with some caution. Lack of results may not be a proof for absence of a relationship between ASD and treatment results in OCSD.

Another important limitation in this study is that there may have been too little variation in the

AQ-scores to be able to find an effect. The average AQ-score in the general population is

16.94 (SD ranges from 0.8-9.7) according to a systematic review of 72 studies (Ruzich et al.,

2015). The study with the most resemblance to this study, the study from Mito et al. (2014), had an ASD+ and ASD- group. The average AQ-score in their ASD- group was 20.9 (5.9), which comes close to the overall average of the total population in this study. The ASD+ group consisted of 28 patients (34.6%) with OCD with an AQ-score ≥32. This indicates that our population scored lower than we would have expected based on the research of Mito et al.(2014). On the basis of the present study it is, therefore, not possible to exclude the assumption that high ASD traits have an impact on the treatment of OCSD.

There are several explanations for the less than expected amount of variation in AQ-score.

According to the Dutch Multidisciplinary Guidelines for Diagnosing and Treating Autism

Spectrum Disorders in Adults (Kan et al., 2013), the AQ is the best instrument so far in screening for ASD and therefore it was used in this study. However, in order to make more assumptions about the efficacy of the treatment, ASD traits should be diagnosed more in- depth. This could be done by using additional case-identifying instruments to determine ASD- traits, like the Social Responsiveness Scale (Bölte et al., 2008). Also, registering ASD- diagnoses or adding a clinical interview (in certain cases) to the research procedure could help determine relevant ASD-traits. Also, with regard to ASD traits, it was surprising that this clinical OCSD sample did not have elevated scores on the AQ. Based on the literature it was expected that people with OCSD would have more ASD-traits than a general population.

Future research should therefore also ascertain there is more variation in the amount of ASD traits, for example by having a large sample size or considering executing the study in an

ASD-specialized setting. Future research should also take into account that additional diagnostic steps have to be taken to measure ASD traits.

Another factor is that recruiting subjects after their treatment could have influenced AQ- scores. It is possible that AQ scores were different in the retrospective assessment, because the AQ scores before the treatment could have been influenced by having OCSD. For example, the AQ contains questions like ‘it is not easy for me to do more than one thing at a time’, ‘I like planning activities carefully’ and ‘I think it is hard to make new friends’.

Therefore, it is imaginable that people with OCSD reply more often affirming on these type of items than people without OCSD, due to symptomatic overlap (like rigidity) or situational circumstances (e.g. being ashamed of OCSD and as a result less social behavior). Therefore it is possible that recruiting retrospectively has affected the AQ-scores. Hoekstra et al. (2008) found that AQ test-scores were stable over time, with a test-retest reliability of r.78, however to date no studies were done regarding test scores on the AQ and comorbid disorders.

Most studies in this area are aimed at anxiety disorders in general or pure OCD. The present study looked at OCSD and included patients with OCD and BDD. It is possible that the inclusion of BDD patients affected the data. Although BDD and OCD have many similarities, such as repetitive behavior, checking behavior, age of onset and duration, (Phillips et a.,

2007), there are some differences as well. People with BDD appear to have poorer insight, for example by being more convinced of certain preoccupations, a higher rate of suicidality than people with OCD and a lower average level of education (Frare et al., 2004; Phillips et al.,

2007). Severity of OCD before the treatment was higher in the BDD-group than the OCD- group. However, both groups seemed to profit from treatment equally. Since this was the main outcome variable in this study, BDD patients were included as well.

Theory

This study showed that CBT for OCSD was not less effective for people with subclinical ASD traits compared to people with no elevated ASD traits. Based on the literature it was expected

that treatment for specifically OCSD could be less effective. Despite methodological limitations of this study, some theoretical points regarding the results can be addressed as well. Results showed that adults with subclinical ASD traits and comorbid OCSD profit from

CBT. This is in line with the research on CBT in anxiety disorders in general and comorbid

ASD for children and adolescents (Storch et al., 2015; Sukhodolsky et al., 2013). However, whether CBT is equally effective in people with clinical ASD remains unclear.

Future research could therefore assess if there are certain components of regular therapy that are more effective for people with ASD. Also, it could help clarify the relation between ASD and OCSD. For example, an obstacle in the treatment of OCSD with comorbid clinical ASD could be that some of the previously mentioned behaviour can be functional in ASD, whereas the same behaviour is dysfunctional in the context of OCSD. Repetitive behaviour can be functional for a person with ASD, because it can help to cope with the unstructured intake of sensory information. 95% of children with ASD report having problems with the unstructured intake of sensory information (Baker et al., 2008). Repetitive behaviours and rituals can be ego-syntonic, because the behaviour is experienced as consisted with what the individual wants. Always rigidly following the same route in the supermarket can be an example of ego- syntonic behaviour, since it can help a person with ASD cope with unstructured sensory information doing the groceries. However, the same behaviour can be experienced as ego- dystonic by a person with OCSD. It is imaginable that treatment will improve for people with clinical ASD if there is more clarity on the role of ego-syntonic repetitive behaviour for people with ASD and OCSD.

To conclude, the current study found no impact from slightly elevated ASD traits on the treatment outcome for OCSD. CBT was effective in the treatment of OCSD for people with subclinical ASD traits. A limitation in this study was that there was little variation in the scores on the AQ, which made it not possible to generalize results to people with high ASD

traits. To exclude the possibility that comorbidity influences scores on the AQ further research has to be done. Also, future studies would profit from additional diagnostic steps in determining the amount of ASD traits and assessing the AQ before the treatment. In addition, it can be helpful to ensure variation in ASD-traits in the population of the study. Also, further research could, based on the literature, focus on the effect the difference between ego- dystonic and ego-syntonic repetitive behaviour in OCSD with comorbid ASD could have on a regular treatment. This study showed that subclinical ASD traits did not have an impact on the efficacy of treatment for OCSD, but it is possible that people with clinical ASD can profit more from an adapted form of therapy. However, to determine if adaptations to the regular treatment program should be necessary additional research should be done. Research on the relation between ASD and OCSD can develop intervention strategies and stress the importance of treating comorbid disorders in ASD.

References

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

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

American Psychiatric Association (2013). Obsessive-Compulsive and Related Disorders. In:

Diagnostic and statistical manual of mental disorders (5th ed.),

doi:10.1176/appi.books.9780890425596.744053.

Allen, A., King, A., & Hollander, E. (2003). Obsessive-compulsive spectrum disorders. Dialogues in clinical neuroscience, 5, 259.

Baker, A., Lane, A., Angley, M. T., & Young, R. L. (2008). The relationship between sensory processing patterns and behavioural responsiveness in autistic disorder: A pilot study. Journal of Autism and Developmental Disorders, 38, 867–875.

Baron-Cohen, S., Wheelwright, S., Skinner, R., Martin, J., & Clubley, E. (2001). The autism spectrum quotient (AQ): Evidence from Asperger syndrome/high-functioning autism, males and females, scientists and mathematicians. Journal of Autism and Developmental Disorders, 31, 5-17.

Bejerot, S. (2007). An autistic dimension: A proposed subtype of obsessive-compulsive disorder. Autism, 11, 101-110.

Bölte, S., Poustka, F., & Constantino, J. N. (2008). Assessing autistic traits: cross‐cultural validation of the social responsiveness scale (SRS). Autism Research, 1, 354-363.

Bradley, E. A., Summers, J. A., Wood, H. L., & Bryson, S. E. (2004). Comparing rates of psychiatric and behaviour disorders in adolescents and young adults with severe intellectual disability with and without autism. Journal of Autism and Developmental Disorders, 34, 151–161.

Brereton, A. V., Tonge, B. J. & Einfeld, S. L. (2006). Psychopathology in Children and Adolescents with Autism Compared to Young People with Intellectual Disability. Journal of Autism and Developmental Disorders, 36, 863-870.

Brugha, T. S., Mcmanus, S., Bankart, J., Scott, F., Purdon, S., Smith, J., Bebbington, P., Jenkins, R. & Meltzer, H. (2011). Epidemiology of Autism Spectrum Disorders in Adults in the Community in England. Archives of General Psychiatry, 68, 459-465.

Chasson, S., Timpano, K. R., Greenberg, J. L., Shaw, A., Singer, T. & Wilhelm, S.(2011). Shared Social Competence Impairment: Another Link Between the Obsessive Compulsive and Autism Spectrums? Clinical Psychology Review, 31, 653-662.

Frare, F., Perugi, G., Ruffolo, G., & Toni, C. (2004). Obsessive–compulsive disorder and body dysmorphic disorder: a comparison of clinical features. European Psychiatry, 19, 292-298.

Gadke, D. L., McKinney, C., & Oliveros, A. (2016). Autism spectrum disorder symptoms and comorbidity in emerging adults. Child Psychiatry & Human Development, 47, 194- 201.

Gillot, A., Furniss, F. & Walter, A. (2001). Anxiety in High-Functioning Children with Autism. Autism, 5, 277-286.

Goodman, W. K., Price, L H., Rasmussen, S. A., Mazure, C., Fleischmann, R. L., Hill, C. L., Heninger, G. R., Charney, D. S. (1989a). The Yale-Brown Obsessive Compulsive Scale. I. Development, Use, and Reliability. Archives of General Psychiatry, 46, 1006 1011.

Goodman, W. K., Price, L H., Rasmussen, S. A., Mazure, C., Fleischmann, R. L., Hill, C. L., Heninger, G. R., Charney, D. S. (1989b). The Yale-Brown Obsessive Compulsive Scale. I. Development, Use, and Reliability. Archives of General Psychiatry, 46, 1006- 1011. van Heijst, B. F., & Geurts, H. M. (2015). Quality of life in autism across the lifespan: A meta-analysis. Autism, 19, 158-167.

Hoekstra, R. A., Bartels, M., Cath, D. C., & Boomsma, D. I. (2008). Factor structure, reliability and criterion validity of the Autism-Spectrum Quotient (AQ): a study in Dutch population and patient groups. Journal of autism and developmental disorders, 38, 1555-1566.

Hofvander, B., Delorme, R., Chaste, P., Nyden, A., Wentz, E., Stahlberg, O., Herbrecht, E., Stopin, A., Anckarsäter, H., Gillberg, C., Rastam, M. & Leboyer, M. (2009). Psychiatric and prosocial problems in adults with normal-intelligence autism spectrum disorders. BioMed Central Psychiatry, 9, 35–43.

Hume, K., Sreckovic, M., Snyder, K., & Carnahan, C. R. (2014). Smooth transitions: Helping students with autism spectrum disorder navigate the school day. TEACHING Exceptional Children, 47, 35-45.

Ivarsson, T., & Melin, K. (2008). Autism spectrum traits in children and adolescents with obsessive-compulsive disorder (OCD). Journal of anxiety disorders, 22(6), 969-978.

Kan, C. C., Geurts, H. M., Bosch, K. van den, Forceville, E. J. M., Manen, J. van, Schuurman, C. H., Sizoo, B. B., Stekelenburg, F., Veldboom, E., Verbeeck, W. J. C., Vrijmoed, D. & Duin, D. van (2013). Multidisciplinaire richtlijn diagnostiek en behandeling van autismespectrumstoornissen bij volwassenen. Utrecht: De Tijdstroom.

Krasny, L., Williams, B. J., Provencal, S., & Ozonoff, S. (2003). Social skills interventions for the autism spectrum: Essential ingredients and a model curriculum. Child and Adolescent Psychiatric Clinics, 12, 107-122.

Lewis, M. H., & Bodfish, J. W. (1998). Repetitive behaviour disorders in autism. Mental retardation and developmental disabilities research reviews, 4, 80-89.

McDougle, C., Kresch, L. E., Goodman, W. K., Naylor, S. T., & Volkmar, F. R. (1995). A case-controlled study of repetitive thoughts and behaviour in adults with autistic disorder and obsessive–compulsive disorder. American Journal of Psychiatry, 152, 772-777.

Meier, S. M., Petersen, L., Schendel, D. E., Mattheisen, M., Mortensen, P. B., & Mors, O. (2015). Obsessive-Compulsive Disorder and Autism Spectrum Disorders: Longitudinal and Offspring Risk. PloS one, 10, 1-11.

Mito, H., Matsuura, N., Mukai, K., Yanagisawa, Y., Nakajima, A., Motoyama, M., ... & Matsunaga, H. (2014). The impacts of elevated autism spectrum disorder traits on clinical and psychosocial features and long-term treatment outcome in adult patients with obsessive-compulsive disorder. Comprehensive psychiatry, 55, 1526-1533.

Neil, N., & Sturmey, P. (2014). Assessment and Treatment of Obsessions and Compulsions in Individuals with Autism Spectrum Disorders: a Systematic Review. Journal of Autism and Developmental Disorders, 1, 62-79.

Ozaki, N., Goldman, D., Kaye, W. H., Plotnicov, K., Greenberg, B. D., Lappalainen, J., Rudnick, G. & Murphy, D. L. (2003). Serotonin transporter missense mutation associated with a complex neuropsychiatric phenotype. Molecular psychiatry, 8, 933 936.

Phillips, K. A., Hollander, E., Rasmussen, S. A., Aronowitz, B. R., DeCaria, C., & Goodman, W. K. (1997). A severity rating scale for body dysmorphic disorder: development, reliability, and validity of a modified version of the Yale-Brown Obsessive Compulsive Scale. Psychopharmological Bulletin, 33, 17-22.

Phillips, K. A., Pinto, A., Menard, W., Eisen, J. L., Mancebo, M., & Rasmussen, S. A. (2007). Obsessive–compulsive disorder versus body dysmorphic disorder: a comparison study of two possibly related disorders. Depression and anxiety, 24, 399-409.

Reaven, J. (2011). The treatment of anxiety symptoms in youth with high-functioning autism spectrum disorders; developmental considerations for parents. Brain Research, 1380, 255-263.

Ruzich, E., Allison, C., Smith, P., Watson, P., Auyeung, B., Ring, H., & Baron-Cohen, S. (2015). Measuring autistic traits in the general population: a systematic review of the Autism-Spectrum Quotient (AQ) in a nonclinical population sample of 6,900 typical adult males and females. Molecular Autism, 6, 1.

Ruzzano, L., Borsboom, D. & Geurts, H. M. (2015). Repetitive Behaviours in Autism and Obsessive-Compulsive Disorder: New perspectives from a Network Analysis. Journal of Autism and Developmental Disorders, 45, 192–202.

Stewart, E., Cancilliere, M. K., Freeman, J., Wellen, B., Garcia, A., Sapyta, J., & Franklin, M. (2016). Elevated Autism Spectrum Disorder Traits in Young Children with OCD. Child Psychiatry & Human Development, 1-9.

Van Steensel, F. J. A., & Bögels, S. M. (2015). CBT for anxiety disorders in children with and without autism spectrum disorders. Journal of consulting and clinical psychology, 83, 512.

Storch, E. A., Lewin, A. B., Collier, A. B., Arnold, E., De Nadai, A. S., Dane, B. F., Nadeau, J. M., Mutch, P. J. & Murphy, T. K. (2015). A randomized controlled trial of cognitive-behavioural therapy versus treatment as usual for adolescents with autism spectrum disorders and comorbid anxiety. Depression and anxiety, 32, 174-181.

Sukhodolsky, D. G., Bloch, M. H., Panza, K. E., & Reichow, B. (2013). Cognitive behavioural therapy for anxiety in children with high-functioning autism: a meta- analysis. Pediatrics, 132, 1341-1350.

Tu, Y.-K (2016). Testing the relation between percentage change and baseline value. Scientific Reports, 6, 23247; doi: 10.1038/srep23247.

Ung, D., Selles, R., Small, B. J., & Storch, E. A. (2015). A systematic review and meta- analysis of cognitive-behavioral therapy for anxiety in youth with high-functioning autism spectrum disorders. Child Psychiatry & Human Development, 46, 533-547.

Vickers, A. J. (2001). The use of percentage change from baseline as an outcome in a controlled trial is statistically inefficient: a simulation study. BMC Medical Research Methodology, 1, 1. de Vries, M., & Geurts, H. (2015). Influence of Autism Traits and Executive Functioning on Quality of Life in Children with an Autism Spectrum Disorder. Journal of autism and Developmental Disorders, 45, 2734-2743.

Woodbury-Smith, M. R., Robinson, J., Wheelwright, S., & Baron-Cohen, S. (2005). Screening adults for Asperger syndrome using the AQ: A preliminary study of its diagnostic validity in clinical practice. Journal of autism and Developmental Disorders, 35, 331-335.

Zandt, F., Prior, M. & Kyrios, M. (2007). Repetitive Behaviour in Children with High Functioning Autism and Obsessive Compulsive Disorder. Journal of Autism and Developmental Disorders, 37, 251-259.

Appendix 1 - Autism-spectrum quotient (in Dutch)

Naam: ………………………………………………. M / V

Geboorte datum: …. - …. - ………

Deze lijst bestaat uit een aantal uitspraken waarmee u het eens of oneens kunt zijn. Lees iedere uitspraak zorgvuldig en kruis dan het antwoord aan dat het meest op u van toepassing is. Voor iedere uitspraak is een viertal antwoordmogelijkheden gegeven: 1 = helemaal mee eens 2 = een beetje mee eens 3 = een beetje mee oneens 4 = helemaal mee oneens.

1 Ik doe liever dingen met anderen dan alleen 1 2 3 4

Ik houd ervan om dingen telkens weer op dezelfde 2 1 2 3 4 manier te doen

Als ik me iets probeer voor te stellen, kan ik daarvan 3 1 2 3 4 heel gemakkelijk een beeld voor ogen krijgen

Ik word regelmatig zo in beslag genomen door iets 4 1 2 3 4 dat ik andere dingen uit het oog verlies

Ik merk vaak zachte geluiden op die anderen niet 5 1 2 3 4 horen

Ik let meestal op nummerplaten van auto’s of 6 1 2 3 4 soortgelijke informatie

Andere mensen zeggen me regelmatig dat wat ik heb 7 gezegd onbeleefd is, zelfs als ik zelf vind dat dat wel 1 2 3 4 beleefd is

Als ik een verhaal lees kan ik me gemakkelijk 8 voorstellen hoe de personages eruit zouden kunnen 1 2 3 4 zien

9 Ik ben gefascineerd door datums 1 2 3 4

In een sociale groep mensen kan ik gemakkelijk de 10 1 2 3 4 gesprekken van verschillende mensen volgen

11 Ik vind sociale situaties gemakkelijk 1 2 3 4

Ik heb de neiging details op te merken die anderen 12 1 2 3 4 niet opmerken

13 Ik ga liever naar de bibliotheek dan naar een feestje 1 2 3 4

14 Ik vind het gemakkelijk om verhalen te verzinnen 1 2 3 4

Ik voel me meer aangetrokken tot mensen dan tot 15 1 2 3 4 dingen

Ik neig naar zeer sterke interesses en raak uit mijn 16 1 2 3 4 doen wanneer ik hiermee niet door kan gaan

17 Ik houd ervan zomaar een praatje te maken 1 2 3 4

Wanneer ik aan het woord ben is het moeilijk voor 18 1 2 3 4 anderen om ertussen te komen

19 Ik ben gefascineerd door getallen 1 2 3 4

Als ik een verhaal lees vind ik het moeilijk om uit te 20 1 2 3 4 vinden wat de bedoelingen van de personages zijn

21 Ik lees niet graag fictie 1 2 3 4

22 Ik vind het moeilijk om nieuwe vrienden te maken 1 2 3 4

23 Ik zie aldoor patronen in dingen 1 2 3 4

24 Ik ga liever naar het theater dan naar een museum 1 2 3 4

Ik raak niet uit mijn doen als mijn dagelijkse routine 25 1 2 3 4 verstoord wordt

Ik realiseer me regelmatig dat ik niet weet hoe ik een 26 1 2 3 4 gesprek gaande moet houden

Ik vind het gemakkelijk om “tussen de regels door te 27 1 2 3 4 lezen” wanneer iemand met me praat

Ik concentreer me meestal meer op het gehele beeld, 28 1 2 3 4 dan op kleine details

Ik ben niet zo goed in het onthouden van 29 1 2 3 4 telefoonnummers

Kleine veranderingen in een situatie of in het uiterlijk 30 1 2 3 4 van iemand vallen mij meestal niet op

Ik merk wanneer iemand die naar mij luistert zich 31 1 2 3 4 gaat vervelen

Ik vind het gemakkelijk om meer dan één ding 32 1 2 3 4 tegelijk te doen

Wanneer ik aan de telefoon ben vind ik het moeilijk 33 om te bepalen wanneer het mijn beurt is om te 1 2 3 4 spreken

34 Ik vind het leuk om dingen spontaan te doen 1 2 3 4

Ik ben vaak de laatste die de clou van een grap 35 1 2 3 4 begrijpt

Ik vind het gemakkelijk om te bepalen wat iemand 36 denkt of voelt door alleen maar zijn zijn/haar gezicht 1 2 3 4 te kijken

Als ik onderbroken word vind ik het gemakkelijk om 37 1 2 3 4 daarna de draad snel weer op te pakken

38 Ik ben goed in het maken van een praatje 1 2 3 4

Mij wordt vaak verteld dat ik maar door blijf gaan 39 1 2 3 4 over één en hetzelfde onderwerp

Toen ik nog klein was vond ik het leuk om alsof- 40 1 2 3 4 spelletjes te doen met andere kinderen

Ik vind het leuk om informatie te verzamelen over 41 bepaalde categorieën (bijvoorbeeld soorten auto’s, 1 2 3 4 soorten vogels, soorten treinen, soorten planten enz.)

Ik vind het moeilijk om me voor te stellen iemand 42 1 2 3 4 anders te zijn

Ik vind het prettig om de activiteiten die ik doe 43 1 2 3 4 zorgvuldig te plannen

44 Ik houd van sociale gelegenheden 1 2 3 4

Ik vind het moeilijk om iemands bedoelingen te 45 1 2 3 4 bepalen

46 Nieuwe situaties maken me bang 1 2 3 4

47 Ik vind het leuk om nieuwe mensen te ontmoeten 1 2 3 4

48 Ik ben een goede onderhandelaar 1 2 3 4

Ik ben niet zo goed in het onthouden van iemands 49 1 2 3 4 geboortedatum

Ik vind het gemakkelijk om met kinderen alsof- 50 1 2 3 4 spelletjes te spelen

Appendix 2 - Yale Brown Obsessive Compulsive Scale (in Dutch)

0 1 2 3 4

1. Tijd besteed aan Geen Lichte mate Matig Ernstig Extreem dwanggedachten (< 1 uur) (1-3 uur) (3-8 uur) (> 8 uur)

2. Belemmering door Geen Gering zonder Duidelijke Duidelijke Tast alle dagelijks verstoring van verstoring van levensaspecten dwanggedachten functioneren te werk of sociale werk of sociale aan schaden contacten, contacten, niet in sociaal functioneren en beheersbaar meer huishoudelijke of beheersbaar beroepsmatige verplichtingen

3. Leed (angst/ onrust) door geen licht Duidelijke angst Ook soms Voortdurende maar onbeheersbare paniek dwanggedachten beheersbaar angst/ paniek

4. Verzet (actief en passief) Altijd, of verzet Meestal verzet In de helft van Soms Nooit is niet nodig de gevallen tegen dwanggedachten

5. Controle over de Volledig Veel In de helft van Weinig Geen de gevallen dwanggedachten

totaal

0 1 2 3 4

1. Tijd besteed aan Geen Lichte mate Matig Ernstig Extreem dwanghandelingen (< 1 uur) (1-3 uur) (3-8 uur) (> 8 uur)

2. Belemmering door Geen Gering zonder Duidelijke Duidelijke Tast alle dagelijks verstoring van verstoring van levensaspecten dwanghandelingen functioneren te werk of sociale werk of sociale aan schaden contacten, contacten, niet in sociaal functioneren en beheersbaar meer huishoudelijke of beheersbaar beroepsmatige verplichtingen

3. Leed (angst/ onrust) door geen licht Duidelijke angst Ook soms Voortdurende maar onbeheersbare paniek niet uitvoeren van beheersbaar angst/ paniek dwanghandelingen

4. Verzet tegen Altijd, of verzet Meestal verzet In de helft van Soms Nooit is niet nodig de gevallen dwanghandelingen

5. Controle over de Volledig Veel In de helft van Weinig Geen de gevallen dwanghandelingen

totaal

TOTAALSCORE