Prevalence of mental disorders in primary care. Implications for screening.

OBJECTIVES: To determine the prevalence of five mental disorders in primary care and to identify patient groups that have a relatively high prevalence of these disorders.
DESIGN: Two-stage case identification design that involves administration of a 16-item screening instrument followed by an independent diagnostic assessment.
SETTING: Three family practice offices in Rhode Island.
SUBJECTS: A total of 937 primary care patients completed the brief screen, 388 of whom completed the independent diagnostic assessment. PREVALENCE ESTIMATION: A Bayesian procedure was used to estimate prevalence of mental disorder from screening and assessment results. Independent assessments were based on the Structured Clinical Interview for DSM-III-R administered by a mental health professional.
RESULTS: The prevalence estimates were alcohol abuse or dependence, 3.2%; generalized anxiety disorder, 2.8%; major depressive disorder, 14.1%; obsessive-compulsive disorder, 2.2%; panic disorder, 6.2%; and any of the five disorders, 22.0%. The prevalence of any of the five disorders was higher in patients returning for follow-up visits (27.9%) than in those either presenting with a new illness (21.7%) or seeking a routine physical examination (11.8%). The combined prevalence was also higher in patients with a chronic medical problem (25.8%) than in those without (16.7%).
CONCLUSIONS: Patients returning for follow-up care and, to a lesser extent, those with chronic medical problems appear to be at increased risk of having a mental disorder. The practice of selectively screening new patients for mental health problems is questioned. Screening efforts in primary care should include established patients and those with chronic medical illnesses as well as new patients.