Dr Ailsa J Russell

Background:  Anxiety disorders, particularly Obsessive Compulsive Disorder (OCD), are commonly reported in young people and adults with Autism Spectrum Disorders (ASD). Psychological treatment has been shown to be effective in treating OCD in the general population but little is known about its effectiveness for people with ASD. A pilot study of Cognitive Behaviour Therapy (CBT) for OCD adapted for adults with ASD showed promising results and suggested that a randomised controlled trial of this intervention was merited.

Objectives:  To conduct a systematic treatment study of CBT for OCD in young people and adults with ASD.

Methods:  Participants were young people (age 14 and older) and adults with ASD and co-morbid OCD who were randomly allocated to 1 of 2 treatments (1) Manualised CBT for OCD adapted for people with ASD (CBT) and (2) Anxiety Management (AM).  Treatments were matched with respect to therapist contact and duration. The primary outcome measure was the total severity rating on the Yale Brown Obsessive Compulsive Scale (Y-BOCS) which was clinician administered blind to treatment group. Informant and self-report symptom measures were also obtained. Follow-up ratings were made at 1, 3, 6 and 12 months post-treatment.

Results:  46 people were randomised to treatment with 20 treatment completers in each group. There was a significant effect of treatment on the primary outcome measure but not of treatment group. Treatment effect sizes on the primary outcome measure were large and could be considered clinically meaningful in the CBT group (0.8-1.1) and medium in the AM group (0.6).  Forty five % of the CBT group were classed as treatment responders compared with 20% in the AM group. Those with mild symptom severity responded well to AM. Almost 40% of people in the AM group opted to try the CBT treatment at 1 month follow-up which differed significantly from the proportion of people in the CBT group choosing to try AM. Secondary analyses indicated that AM might augment the effects of later CBT.  None of the variables predicted to be moderating factors (Theory of Mind, Verbal and planning abilities and scores on the Autism Diagnostic Observation Schedule) were associated with treatment outcome.

Conclusions:  Psychological treatment in the form of cognitive and behavioural therapies are effective in treating co-morbid OCD in people with ASD.  Further investigations should seek to refine treatment protocols to consider the precise adaptations to conventional psychological treatment which are most effective for this group.