Clinical trials studying pharmacotherapy and psychological treatments alone and together.

Pharmacologic treatment of pain has made tremendous advances in recent years, and multiple clinical trials support the usefulness of psychological interventions in reducing pain, disability, and even costs, in a number of chronically painful conditions. Despite the widespread use of combined pharmacologic and psychological treatments in clinical care, little is known about the potential for these two very different types of interventions to provide additive or possibly synergistic effects. After briefly reviewing of the clinical trial literature comparing and combining psychological and pharmacologic interventions for chronically painful conditions, this article discusses two key challenges to future trials. The first section encourages investigators to systematically identify the parameters that limit or enhance the efficacy of pharmacologic, psychological, and combined treatments. Strategies for addressing adherence and drop-outs, identifying nonresponders and other subgroups, understanding the impact of selection factors, and delineating treatment characteristics need to be developed. The second challenge pertains to issues of trial design when pharmacologic and psychological treatments for pain are compared and combined. Trials comparing active treatments that are as diverse as psychological and pharmacologic treatments require specific features, such as large sample sizes, active placebo controls, both immediate and delayed outcome assessments, and broad measures of outcome that include health-care utilization and cost. Some lessons learned from the psychiatric literature comparing and combining psychological and pharmacologic treatments are integrated into recommendations for future trials evaluating existing and new treatments for chronically painful conditions.