Supplementary Material for: Long-Term Effectiveness of Cognitive Behavioral Therapy in Routine Outpatient Care: A 5- to 20-Year Follow-Up Study

Objective: Long-term follow-ups several years after receiving cognitive behavioral therapy (CBT) are scarce and most of the existing literature describes follow-up data of randomized-controlled trials. Thus, very little is known about the long-term effects of CBT in routine care. Methods: We investigated psychological functioning in a sample of 263 former outpatients who had received CBT for a variety of mental disorders such as depression, anxiety-, eating- or somatoform disorders 8.06 (SD 5.08) years after treatment termination. All participants completed a diagnostic interview as well as the Brief-Symptom Inventory (BSI) and the Beck Depression Inventory (BDI). Effect sizes and response rates according to Jacobson and Truax [J Consult Clin Psychol 1991;59:12–9] were calculated from pre- to posttreatment and from pretreatment to follow-up assessment. Results: Pre- to posttreatment effect sizes ranged between 0.75 (BDI) and 0.63 (BSI) and pretreatment to follow-up effect sizes were 0.92 (BDI) and 0.75 (BSI). Of all patients, 29% (BDI) and 17% (BSI) experienced clinically significant change at posttreatment and 42% (BDI) and 24% (BSI) at follow-up. Conclusion: The results point to the long-term effectiveness of CBT under routine conditions for a wide array of problems, especially when compared to the long-term effects of medical treatment. It is noteworthy that the results at follow-up were even better than at posttreatment, indicating further improvement. However, about a quarter of the patients did not respond sufficiently to therapy, neither concerning short-term nor long-term effects.