Efficacy trials suggest that structured psychological therapies may significantly reduce recurrence rates of major mood episodes in individuals with bipolar disorders. However, clinicians also need to know whether interventions targeted at homogeneous research populations can be applied to the more complex and heterogenous populations seen in day to day practice. The MRC UK funded a large scale multicentre pragmatic, randomized controlled treatment trial (N=253) in which patient outcomes were assessed every 8 weeks for18 months by researchers blinded to group allocation and all data were analyzed by an independent statistician. In this effectiveness study, more than half of the patients had a recurrence by 18 months, and there were no significant differences in outcomes between groups (hazard ratio=1.05; 95% CI 0.74-1.50).

However, the well-known headline findings do not tell the whole story of this trial. For example, we have now undertaken a series of dismantling studies that have allowed us to determine specific characteristics of responders and non-responders to adjunctive CBT. It was found that when the sub-sample with similar features to samples in efficacy studies are identified, their reductions in relapse rates with CBT are remarkably similar to achieved in other studies. Also, that CBT response rates in those with acute depression were similar to those achieved in the STEP-BD study of therapies.

Criticisms of the study methodology have rightly identified that the heterogeneity of the patient population is a potential barrier to truly understanding whether CBT can be helpful in clinical practice. However, the extension of the analyses in this pragmatic study has allowed us to identify that people with bipolar disorder and comparatively fewer previous manic episodes may benefit from CBT for acute bipolar depression, and those in the early stages of their bipolar 'career' may be the best candidates for CBT for relapse prevention. The effectiveness trial also allowed us to highlight that such cases form the minority of those receiving mental healthcare- a finding that offers important insights when attempting to translate research findings into real world clinical practice.