Effectiveness of psychotherapy and combination treatment for chronic depression.

Although considerable research has been conducted on the efficacy of psychotherapy for depression, with and without medication, relatively few studies have focused on chronic forms of depression. Approximately 20% of individuals with depression experience episodes that last for two years or longer. We review the controlled research on the effectiveness of treatments separately for dysthymia and chronic major depression, focusing on the practical implications of the research for clinicians. In trials conducted with dysthymics, medication has been superior to psychotherapy, with limited evidence that combined treatment has advantages over medication or psychotherapy alone. In chronic major depression, combined treatment has demonstrated significant superiority over medication or psychotherapy alone. Possible explanations for the discrepant findings among dysthymics and those with chronic major depression are discussed.