Effectiveness of long-term psychodynamic psychotherapy: a meta-analysis.

To examine the effects of LTPP, especially in complex mental disorders, ie, patients with personality disorders, chronic mental disorders, multiple mental disorders, and complex depressive and anxiety disorders (ie, associated with chronic course and/or multiple mental disorders), by performing a meta-analysis. DATA SOURCES: Studies of LTPP published between January 1, 1960, and May 31, 2008, were identified by a computerized search using MEDLINE, PsycINFO, and Current Contents, supplemented by contact with experts in the field. STUDY SELECTION: Only studies that used individual psychodynamic psychotherapy lasting for at least a year, or 50 sessions; had a prospective design; and reported reliable outcome measures were included. Randomized controlled trials (RCTs) and observational studies were considered. Twenty-three studies involving a total of 1053 patients were included (11 RCTs and 12 observational studies). DATA EXTRACTION: Information on study characteristics and treatment outcome was extracted by 2 independent raters. Effect sizes were calculated for overall effectiveness, target problems, general psychiatric symptoms, personality functioning, and social functioning. To examine the stability of outcome, effect sizes were calculated separately for end-of-therapy and follow-up assessment.

According to comparative analyses of controlled trials, LTPP showed significantly higher outcomes in overall effectiveness, target problems, and personality functioning than shorter forms of psychotherapy. With regard to overall effectiveness, a between-group effect size of 1.8 (95% confidence interval [CI], 0.7-3.4) indicated that after treatment with LTPP patients with complex mental disorders on average were better off than 96% of the patients in the comparison groups (P = .002). According to subgroup analyses, LTPP yielded significant, large, and stable within-group effect sizes across various and particularly complex mental disorders (range, 0.78-1.98).