A randomized controlled trial of cognitive therapy versus intensive behavior therapy in obsessive compulsive disorder

The study was designed to compare cognitive therapy (CT) with intensive behavior therapy (BT) in obsessive-compulsive disorder (OCD) and to study their change process.

Sixty-five outpatients with DSM-4 OCD were randomized into 2 groups for 16 weeks of individual treatment in 3 centers. Group 1 received 20 sessions of CT. Group 2 received a BT program of 20 h in two phases: 4 weeks of intensive treatment (16 h), and 12 weeks of maintenance sessions (4 h). No medication was prescribed.

Sixty-two patients were evaluated at week 4, 60 at week 16 (post-test), 53 at week 26 and 48 at week 52 (follow-up). The response rate was similar in the 2 groups. The Beck Depression Inventory (BDI) was significantly more improved by CT (p = 0.001) at week 16. The baseline BDI and Obsessive Thoughts Checklist scores predicted a therapeutic response in CT, while the baseline BDI score predicted a response in BT. At week 16, only the changes in Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and a scale measuring the interpretation of intrusive thoughts correlated in CT, while the changes in Y-BOCS, BDI, and interpretation of intrusive thoughts correlated in BT. Improvement was retained at follow-up without a between-group difference. The intent-to-treat analysis (last observation carried forward) found no between-group differences on obsessions, rituals and depression.

CT and BT were equally effective on OCD, but at post-test CT had specific effects on depression which were stronger than those of BT. Pathways to improvement may be different in CT and BT. The outcomes are discussed in the light of an effect size analysis.