Avoidable pitfalls in behavioral medicine outcome research.

To secure the role of behavioral medicine in health care, researchers continue to improve the quality of their outcome studies. Despite the availability of guidelines for designing high quality clinical trials, however, we have noted two, unfortunately common, flaws in behavioral medicine outcome research that undermine these efforts. The first issue is that researchers recruit medical patients whose scores on psychological target measures are not elevated at pretest. Data are presented from quantitative reviews of cardiovascular and cancer populations to illustrate the impact of this protocol decision. It is demonstrated how magnitude of change and corresponding statistical power are greatly reduced when patients with few problems are enrolled. The second issue pertains to the failure of researchers to measure psychological change when the actual model to be tested is a mediational model such that successful treatment of psychological distress is presumed to account for good long-term health outcomes. Such lack of attention to protocol design can result in misinterpretation of obtained effects and can lead to premature dismissal of psychological treatment opportunities for physical disease. We suggest how these flaws can be avoided in the protocol design stage.