What happens after group CBT for anxiety and related disorders? Preliminary investigation of treatment outcomes over time in a naturalistic sample

BACKGROUND: Cognitive behavioural therapy (CBT) is the first-line treatment for anxiety and related disorders. Limited research has explored long-term outcomes following CBT for anxiety-related disorders in naturalistic settings, particularly for generalized anxiety disorder (GAD), social anxiety disorder (SAD), and post-traumatic stress disorder (PTSD). AIMS: This study examined long-term outcomes and attrition after group CBT for GAD, SAD, and PTSD in a naturalistic sample. Across disorders, it was hypothesized that gains would be maintained long-term, with a gradual return of clinically relevant symptoms observed at later follow-up points. METHOD: Data were collected from individuals completing CBT at a tertiary anxiety treatment clinic. Symptom changes pre- to post-treatment and over a 2-year follow-up were examined, as well as the influence of baseline depressive symptoms on change over time. Worry, social anxiety, and post-traumatic stress symptoms were assessed at pre- and post-treatment and 3, 6, 9, 12, and 24 months. RESULTS: On average, symptom improvements were maintained over the 2-year follow-up for all disorders. Higher pre-treatment depression was associated with greater symptom severity throughout the study but generally did not affect the magnitude of symptom change. The exception was PTSD, where baseline depression was also associated with changes in symptom severity across the whole study period. This effect was not observed for those with SAD and GAD. Attrition was high across the follow-up period. CONCLUSION: This study provides preliminary evidence for the long-term efficacy of CBT in a naturalistic setting. It also highlights challenges with retaining clients in long-term follow-up in naturalistic settings.