Personalized treatment of adult depression: medication, psychotherapy, or both? A systematic review.

BACKGROUND Personalized medicine aims to identify which characteristics of an individual predict the outcome of a specific treatment, in order to get a better match between the individual and the treatment received. We conducted a systematic review and meta-analysis of randomized trials comparing two treatments directly in a group of patients with a specific characteristic. METHODS We searched relevant studies from bibliographical databases and included trials comparing (1) medication with psychotherapy, (2) medication with combined treatment, and (3) psychotherapy with combined treatment, in specific target groups (a) with a predefined sociodemographic characteristic, (b) a specific type of depression, (c) a comorbid mental or somatic disorder, or (d) from a specific setting (outpatients, primary care). RESULTS We included 52 studies with 4,734 depressed patients. In these studies, 20 characteristics of the target groups were examined. The results showed that medication is probably the best treatment for dysthymia, and combined treatments are more effective in depressed outpatients, as well as in depressed older adults. However, in order to examine the 20 characteristics in the three categories of comparisons, 254 studies would be needed for having sufficient statistical power to show an effect size of g = 0.5. Currently, only 20.1% of these studies have been conducted. CONCLUSIONS Although a considerable number of studies have compared medication, psychotherapy, and combined treatments, and some preliminary results are useful for deciding which treatment is best for which patient, the development of personalized treatment of depression has only just begun.