The impact of treatment delivery format on response to cognitive behaviour therapy for preadolescent children with anxiety disorders

Background: Several delivery formats of cognitive behaviour therapy (CBT) for child anxiety have been proposed, however, there is little consensus on the optimal delivery format. The primary goal of this study was to investigate the impact of the child's primary anxiety diagnosis on changes in clinical severity (of the primary problem) during individual CBT, group CBT and guided parent-led CBT. The secondary goal was to investigate the impact of the child's primary anxiety diagnosis on rates of remission for the three treatment formats. Methods: A sample of 1,253 children (5-12 years; Mage = 9.3, SD = 1.7) was pooled from CBT trials carried out at 10 sites. Children had a primary diagnosis of generalised anxiety disorder (GAD), social anxiety disorder (SoAD), specific phobia (SP) or separation anxiety disorder (SAD). Children and parents completed a semistructured clinical interview to assess the presence and severity of DSM-IV psychiatric disorders at preintervention, postintervention and follow-up. Linear mixture modelling was used to evaluate the primary research question and logistic modelling was used to investigate the secondary research question. Results: In children with primary GAD, SAD or SoAD, there were no significant differences between delivery formats. However, children with primary SP showed significantly larger reductions in clinical severity following individual CBT compared to group CBT and guided parent-led CBT. The results were mirrored in the analysis of remission responses with the exception that individual CBT was no longer superior to group CBT for children with a primary SP. The difference between individual and group was not significant when follow-up data were examined separately. Conclusions: Data show there may be greater clinical benefit by allocating children with a primary SP to individual CBT, although future research on cost-effectiveness is needed to determine whether the additional clinical benefits justify the additional resources required.