Is longer-term psychodynamic psychotherapy more effective than shorter-term therapies? Review and critique of the evidence.

BACKGROUND In 2008, Leichsenring and Rabung performed a meta-analysis of 8 studies of longer-term psychodynamic psychotherapy (LTPP). The work was published in the Journal of the American Medical Association (vol. 300, pp 1551-1565), and they concluded that LTPP was more effective than shorter-term therapies. METHOD Given that such claims have the potential to influence treatment decisions and policies, we re-examined the meta-analysis and the 8 studies. RESULTS We found a miscalculation of the effect sizes used to make key comparisons. Claims for the effectiveness of LTPP depended on a set of small, underpowered studies that were highly heterogeneous in terms of patients treated, interventions, comparison-control groups, and outcomes. LTPP was compared to 12 types of comparison-controls, including control groups that did not involve any psychotherapy, short-term psychodynamic psychotherapy, and unvalidated treatments. Additionally, the studies failed to protect against threats to bias, and had poor internal validity. CONCLUSION Overall, we found no evidence to support claims of superiority of LTPP over shorter-term methods of psychotherapy.