Why is this review important?

Depression is a common mental disorder characterised by sadness, loss of pleasure in most activities, feelings of worthlessness or guilt, thoughts of death or suicide. Couple therapy has been suggested as a treatment for couples with a depressed partner on the basis of the association between depressive symptoms and relationship distress, the role of relational negative factors in onset and maintenance of depression, and the buffering effect of intimacy and interpersonal support. Couple therapy works by modifying negative interactional patterns and increasing mutually supportive aspects of relationships. It is important to know whether couple therapy can help people with depression.

Who will be interested in this review?

This review will be of interest to people with depression, their partners, and people involved in their care.

What questions does this review aim to answer?

This review aimed to assess evidence about the effects of couple therapy for couples with a depressed partner.

Which studies were included in the review?

We considered studies of couple therapy delivered in outpatient settings to couples in which a partner had a clinical diagnosis of depressive disorder. We included 14 studies with 651 participants .Thirteen of the studies were randomised controlled trials, where participants were assigned by chance alone to the couple therapy treatment group or usual care. However, one study was not completely randomised due to therapist availability.

What does the evidence from the review tell us?

There was low-quality evidence to suggest that couple therapy is as effective as individual psychotherapy in improving depression. People with depression might do better when receiving couple therapy compared with no treatment, but we are very uncertain about this effect because of the very low quality of studies. In comparison with treatment with antidepressant medication, limited data was available. Although data on few dropouts favour couple therapy, the very low quality of data seriously weakens this finding. The comparison between couple therapy plus antidpressant medication and antidepressants alone showed no difference in depressive symptom level, but the results were based on two small studies. Couple therapy was more effective in reducing relationship distress than individual psychotherapy and this effect was enhanced when distressed couples were considered separately. However, this result has to be considered with great caution, because of the very low quality of studies. Most studies were affected by small sample sizes, unclear sample representativeness, loss of participants at follow-up, and investigators’ allegiance bias. Moreover, there were few follow-ups that went beyond 6 months post-treatment. Only one study tested whether improvements in couple relationships led to improvement in depression, finding supporting evidence for that. However, the small sample of this study and the lack of other studies which investigated this hypothesis means we could not test in this review if this finding was supported. Although it is difficult to draw conclusions with any confidence on differences between couple therapy and other treatments for depression, the possibility of improvement in couple relationships may favour its choice when relationship distress is a major problem.

What should happen next?

We need good quality trials, testing in large samples with long follow-up of the effects of couple therapy in comparison to other interventions, especially in distressed couples.