Methodologic issues in randomized trials of liaison psychiatry in primary care.

Most anxiety, depressive, and substance abuse disorders are treated exclusively in the primary care health system. However, recognition and treatment of these disorders in primary care is deficient. Psychopharmacologic and psychotherapeutic interventions have been developed and proven effective in randomized trials in specialty care. However, the results of successful trials of mental health interventions in specialty settings may not generalize to primary care settings because of epidemiologic differences in patients, differences in skills of providers, as well as differences in the very structure of care. The importance of the development of innovative randomized trials to improve recognition and treatment of mental illness in primary care is emphasized, as well as the methodologic problems inherent in carrying out these trials.