Is CBT As Effective for Treating Anxiety Disorders in Children and Adolescents with ASD As for Typically Developing Children, Also in the Long Term? Preliminary Results of a Controlled Clinical Trial

Background: Anxiety disorders are highly common among children with autism spectrum disorders (ASD). Although several studies have demonstrated the effectiveness of Cognitive Behavioral Therapy (CBT) for the treatment of anxiety disorders in children with ASD, little is known about (1) the effectiveness in the long term, (2) the factors that are associated with treatment effectiveness, or (3) how effective CBT is when compared to typically developing children.

Objectives: The aim of this study was to evaluate the (long term) effectiveness of CBT for the treatment of anxiety disorders in children with and without ASD, and to examine which factors are associated with treatment effectiveness one year later.

Methods: In this study, 99 clinically referred children aged 7-18 years, and their parents, participated. The sample consisted of 53 children diagnosed with ASD and comorbid anxiety disorders and 46 children diagnosed with anxiety disorders (without ASD). Interviews assessing anxiety disorders, and questionnaires assessing anxiety symptoms, ASD-symptoms, child psychopathology, parental anxiety, and family functioning were administered at pre- and post-treatment, three months after CBT, and one year after CBT.

Results: According to ADIS-parent report, 71.7% of the children with ASD were free of their primary anxiety disorder one year after CBT against 90.6% of the children without ASD (p < .05). For ADIS-child report these rates were 66.7% and 96.3%, respectively (p < .05). (Of note, for post-treatment and 3 months after CBT no differences were found). Treatment effectiveness for all anxiety disorders was investigated with repeated measures (M)ANOVA. Results indicated that the total severity of anxiety disorders decreased over time (p < .05). Moreover, a significant group effect was found for parental report, indicating that parents of children with ASD report more (severe) anxiety disorders compared to the children without ASD. However, no significant interaction effect was found (p > .10), suggesting no differences in improvement between children with and without ASD. Furthermore, it was found that demographic variables (gender and age) did not correlate with treatment effectiveness, whereas several variables of family functioning (measured pre-treatment) did. However, significant correlations between treatment effectiveness and family functioning differed per respondent (child, mother and father) and per group (children with ASD versus children with anxiety disorders). Family un-involvement was negatively correlated with treatment effectiveness for both groups. For the children with ASD specifically, treatment effectiveness was negatively correlated to paternal anxiety, active-reactive orientation and sociability of the family. For the children with anxiety disorders specifically, treatment effectiveness was negatively correlated with a laissez-faire family style, and positively correlated with cohesion and a democratic family style.

Conclusions: At one year follow-up, CBT is less effective for the children with ASD compared to the children without ASD when considering dichotomous outcome measures (percentage free of primary anxiety disorder). However, considering the treatment effectiveness for the total anxiety severity score, CBT is equally effective for children with and without ASD, also at one year follow-up. In addition, family functioning at pre-treatment may be an important factor for treatment effectiveness in both groups.