Effectiveness of Psychological Treatments for Depressive Disorders in Primary Care: Systematic Review and Meta-Analysis

The systematic review by Linde et al. summarizes the evidence on psychological treatments in adult depressed primary care patients - a topic of major importance. In their methodologically sound analyses, the authors found evidence that psychological treatments are effective in depressed primary care patients and no evidence for clear differences in outcome between the investigated treatment concepts.

Although the discussion of the results in the article is in general quite well balanced, I would like to question one conclusion the authors drew. They concluded that an "eclectic rather than a dogmatic approach should be favored". This wording might lead to a misinterpretation of the results and might be understood as if we had evidence for all psychological interventions in this setting, or evidence for freely combined different therapeutic approaches. But this is not the case.

The main body of evidence (a total of 30 studies were included) is based on cognitive behavioral therapy (CBT; 18 studies), problem-solving therapy (PST; 6 studies), and interpersonal psychotherapy (IPT; 2 studies). Four studies were categorized as "psychosocial therapies", but there were no studies on psychodynamic or systemic therapies. CBT and PST share many characteristics and PST is sometimes even subsumed under the label of CBT. Moreover, the intervention in one of the studies (that was) categorized as "psychosocial therapy" is described as "psychoeducation", an approach closely linked to CBT and usually part of all CBT manuals.

Therefore, the evidence for depression treatment in primary care is strongly predominated by CBT-related therapy approaches. We have no rationale to generalize the positive findings to other psychological approaches that have not been investigated.

As none of the included studies investigated the effects of an eclectic approach, we have no direct evidence for the combination of elements from different approaches. I would therefore conclude that there is evidence for different therapeutic approaches, namely CBT, PST, and IPT. The authors found no evidence for the use of other therapies or an eclectic approach in primary care.

Of course it is an interesting (but not surprising) finding that different approaches seem equally effective, however, we need a better understanding of common characteristics and therapeutic ingredients of different approaches in order to be able to build heuristics for combining them. To investigate the effects of other therapies or eclectic approaches in primary care might be an interesting target of future research, but these approaches cannot yet be considered evidence based.

Competing interests: None declared