Psychological factors in chronic pain: Evolution and revolution.

The complexity of chronic pain has represented a major dilemma for clinical researchers interested in the reliable and valid assessment of the problem and the evaluation of treatment approaches. The West Haven-Yale Multidimensional Pain Inventory (WHYMPI) was developed in order to fill a widely recognized void in the assessment of clinical pain. Assets of the inventory are its brevity and clarity, its foundation in contemporary psychological theory, its multidimensional focus, and its strong psychometric properties. Three parts of the inventory, comprised of 12 scales, examine the impact of pain on the patients' lives, the responses of others to the patients' communications of pain, and the extent to which patients participate in common daily activities. The instrument is recommended for use in conjunction with behavioral and psychophysiological assessment strategies in the evaluation of chronic pain patients in clinical settings. The utility of the WHYMPI in empirical investigations of chronic pain is also discussed.

Sixty-five studies that evaluated the efficacy of multidisciplinary treatments for chronic back pain were included in a meta-analysis. Within- and between-group effect sizes revealed that multidisciplinary treatments for chronic pain are superior to no treatment, waiting list, as well as single-discipline treatments such as medical treatment or physical therapy. Moreover, the effects appeared to be stable over time. The beneficial effects of multidisciplinary treatment were not limited to improvements in pain, mood and interference but also extended to behavioral variables such as return to work or use of the health care system. These results tend to support the efficacy of multidisciplinary pain treatment; however, these results must be interpreted cautiously as the quality of the study designs and study descriptions is marginal. Suggestions for improvement in research designs as well as appropriate reports of research completed are provided.