The role of CBT in explicit memory bias in bipolar I patients.

Background And Objectives: Cognitive and Behavioural Therapy (CBT) is widely used in bipolar disorder, but recent meta-analyses showed that its impact is either of limited effect or not significant for important aspects such as recurrence rate. A possible benefit of CBT could concern cognitive functions, known to be frequently impaired in patients with bipolar disorder. We analysed if the positive impact of 6 months group-CBT was associated with the improvement of a specific cognitive function, namely explicit memory, trying to disentangle if memory bias (i.e. different capacity according to the emotional valence of words to be recalled) was more improved than memory performance (i.e., total number of recalled words).

Methods: Depressive, manic, anxiety symptoms and explicit memory for emotional words were initially assessed in 68 remitted bipolar I patients. Six months later, with an attrition rate of 16.2%, patients were re-assessed after CBT (N = 42) or as control condition (waiting list, N = 15). The expected impact of CBT was assessed through the improvement in the Dysfunctional Attitudes Scale.

Results: After CBT, an increase was observed for the number of neutral, positive and total words recalled, whereas the number of negative words recalled decreased. This increase was still significant when the improvement of dysfunctional attitudes and mood symptoms are taken into account.

Limitations: The small sample of control patients.

Conclusions: CBT was effective, as it improved dysfunctional attitudes and reduced remaining symptoms, but also, and independently, it improved explicit memory performance while reducing memory bias in favour of negative words.