The National Institute of Mental Health sponsored a research workshop in 1999 to examine the potential of various theoretical approaches for enhancing adherence and behavior change, with special attention to mental disorders as mediators and outcomes. Complementary, multiple levels of analysis--including individual, small-group, community, and cultural perspectives--were considered. Working groups identified problems and gaps in knowledge that if addressed would transform adherence and behavior change from overlooked or nuisance variables to critical variables in research on mental and medical disorders.