Objective: In a previous randomized controlled study, the authors reported significant beneficial effects of cognitive therapy for relapse prevention in bipolar disorder patients up to 1 year. This study reports additional 18-month follow-up data and presents an overview of the effect of therapy over 30 months.
Method: Patients with DSM-IV bipolar I disorder (N=103) suffering from frequent relapses were randomly assigned into a cognitive therapy plus medication group or a control condition of medication only. Independent raters, who were blind to patient group status, assessed patients at 6-month intervals.
Results: Over 30 months, the cognitive therapy group had significantly better outcome in terms of time to relapse. However, the effect of relapse prevention was mainly in the first year. The cognitive therapy group also spent 110 fewer days (95% CI=32 to 189) in bipolar episodes out of a total of 900 for the whole 30 months and 54 fewer days (95% CI=3 to 105) in bipolar episodes out of a total of 450 for the last 18 months. Multivariate analyses of variance showed that over the last 18 months, the cognitive therapy group exhibited significantly better mood ratings, social functioning, coping with bipolar prodromes, and dysfunctional goal attainment cognition.
Conclusions: Patients in the cognitive therapy group had significantly fewer days in bipolar episodes after the effect of medication compliance was controlled. However, the results showed that cognitive therapy had no significant effect in relapse reduction over the last 18 months of the study period. Further studies should explore the effect of booster sessions or maintenance therapy.