The various forms of chronic depression account for about 1/3 of depressive disorders. Chronic depression is characterized by low rates of spontaneous remissions, requiring longer and more intense treatment than episodic depression. While considerable research has confirmed the efficacy of specific psychotherapies in the treatment of episodic depression, only few studies have addressed chronic depression.

To assess the efficacy of specific psychotherapies in chronic depression and to provide recommendations for future research.

Systematic review of the literature.

Identified studies varied largely regarding sample sizes, outcome criteria, and characteristics of treatment. Limited research suggests that more traditional approaches (CBT, IPT) have shown only modest success in the treatment of chronic depression. The Cognitive Behavioral Analysis System of Psychotherapy (CBASP), combining behavioural, cognitive, and interpersonal strategies, has demonstrated good efficacy in combination with medication in one large study so far. In general, combinations of pharmacotherapy and psychotherapy appear to improve treatment effects with regard to broader outcome criteria and longterm outcome.

A broader empirical basis is needed to allow firmer conclusions on the efficacy of different types of psychotherapy in chronic depression. Larger randomized studies are needed, particularly those investigating additive effects of combined treatment, comparisons of specific interventions, and dose-related outcomes. It may also be necessary to expand traditional short-term approaches by designing studies which explicitly adopt suggested model-specific options for chronicity. Studies should also consider possible predictors of outcome, such as early versus late onset and comorbidity, as well as health economic aspects.