Common mental disorders and disability across cultures. Results from the WHO Collaborative Study on Psychological Problems in General Health Care

OBJECTIVE: To examine the impact of common mental illness on functional disability and the cross-cultural consistency of this relationship while controlling for physical illness. A secondary objective was to determine the level of disability associated with specific psychiatric disorders. DESIGN: A cross-sectional sample selected by two-stage sampling. SETTING: Primary health care facilities in 14 countries covering most major cultures and languages. PATIENTS: A total of 25,916 consecutive attenders of these facilities were screened for psychopathology using the General Health Questionnaire (96% response). Screened patients were sampled from the General Health Questionnaire score strata for the second-stage Composite International Diagnostic Interview administered to 5447 patients (62% response). MAIN OUTCOME MEASURES: Patient-reported physical disability, number of disability days, and interviewer-rated occupational role functioning. RESULTS: After controlling for physical disease severity, psychopathology was consistently associated with increased disability. Physical disease severity was an independent, although weaker, contributor to disability. A dose-response relationship was found between severity of mental illness and disability. Disability was most prominent among patients with major depression, panic disorder, generalized anxiety, and neurasthenia; disorder-specific differences were modest after controlling for psychiatric comorbidity. Results were consistent across disability measures and across centers. CONCLUSIONS: The consistent relationship of psychopathology and disability indicates the compelling personal and socioeconomic impact of common mental illnesses across cultures. This suggests the importance of impairments of higher-order human capacities (eg, emotion, motivation, and cognition) as determinants of functional disability.