How well do Cognitive Behavioural Therapy and Behavioural Activation for depression repair anhedonia? A secondary analysis of the COBRA randomized controlled trial

A secondary analysis of the COBRA randomized controlled trial was conducted to examine how well Cognitive Behavioural Therapy (CBT) and Behavioural Activation (BA) repair anhedonia. Patients with current major depressive disorder (N = 440) were randomized to receive BA or CBT, and anhedonia and depression outcomes were measured after acute treatment (six months) and at two further follow up intervals (12 and 18 months). Anhedonia was assessed using the Snaith Hamilton Pleasure Scale (SHAPS; a measure of consummatory pleasure). Both CBT and BA led to significant improvements in anhedonia during acute treatment, with no significant difference between treatments. Participants remained above healthy population averages of anhedonia at six months, and there was no further significant improvement in anhedonia at 12-month or 18-month follow up. Greater baseline anhedonia severity predicted reduced repair of depression symptoms and fewer depression-free days across the follow-up period in both the BA and CBT arms. The extent of anhedonia repair was less marked than the extent of depression repair across both treatment arms. These findings demonstrate that CBT and BA are similarly and only partially effective in treating anhedonia. Therefore, both therapies should be further refined or novel treatments should be developed in order better to treat anhedonia.