Researchers from the VU University in Amsterdam and the EMGO Institute have published a nice summary of the effects of psychotherapies for adult depression. The study summarises a series of meta-analyses that they have carried out, to measure the strength of the evidence for the different types of psychotherapy in treating different types of depression.

Here’s what they found:

• Different types of psychotherapy are efficacious in the treatment of adult depression, including:
• Cognitive behaviour therapy
• Interpersonal psychotherapy
• Problem-solving therapy
• Non-directive supportive therapy
• Behavioural activation therapy
• Differences in effect size between types of psychotherapy are small
• Psychotherapies are about as effective as antidepressants in treating mild to moderate depression
• Combined treatment is more effective than psychotherapy or antidepressants alone
• Psychotherapy is an effective treatment for:
• Depressed adults in general
• Older adults
• Women with postpartum depression
• Patients with general medical disorders
• Inpatients
• Primary care patients
• Patients with chronic depression
• Patient with sub-threshold depression

The research team concluded:

We found no evidence showing that psychotherapy is less efficacious in severe depression (with mean baseline Hamilton Depression Rating Scale scores up to 31, mean Beck Depression Inventory scores up to 35.85 and mean Beck Depression Inventory-II scores up to 36.50), but effects are smaller in chronic depression.

We also found that the effects of psychotherapy are probably overestimated because of publication bias and the relatively low quality of many studies in the field.

Cuijpers P, Andersson G, Donker T, van Straten A. Psychological treatment of depression: Results of a series of meta-analyses. Nord J Psychiatry. 2011 Jul 20. [Epub ahead of print] [PubMed abstract]