Psychotherapy and survival in cancer: the conflict between hope and evidence.

Despite contradictory findings, the belief that psychotherapy promotes survival in people who have been diagnosed with cancer has persisted since the seminal study by D. Spiegel, J. R. Bloom, H. C. Kramer, and E. Gottheil (1989). The current authors provide a systematic critical review of the relevant literature. In doing so, they introduce some considerations in the design, interpretation of results, and reporting of clinical trials that have not been sufficiently appreciated in the behavioral sciences. They note endemic problems in this literature. No randomized clinical trial designed with survival as a primary endpoint and in which psychotherapy was not confounded with medical care has yielded a positive effect. Among the implications of the review is that an adequately powered study examining effects of psychotherapy on survival after a diagnosis of cancer would require resources that are not justified by the strength of the available evidence.