The burden of mental disorders in primary care.

OBJECTIVES

To describe and compare the prevalence of mental disorders across primary care populations, and estimate their impact on quality of life.

METHODS

Cross-sectional multilevel analysis of a systematic sample of 2539 attendees to eight primary care centres in different regions of Spain, assessed with the WHO Composite International Diagnostic Interview (CIDI 1.1), the Short Form Health Survey (SF-36) quality of life questionnaire and the SF-6D utility index.

RESULTS

The 12-month prevalence of any mental disorder was 23% (95% confidence interval: 21-24%), 10% had mood, 9% anxiety, 5% organic, 4% somatoform, and 1% alcohol use disorders, with a significant between-centre variability (P<0.001). People with mental disorders had one standard deviation lower mental quality of life than the general population. We estimated that 1831 quality-adjusted life-years (QALYs) are lost annually per 100,000 patients due to mental disorders, without considering mortality. Mood disorders have the worst impact with an annual loss of 1124 QALYs per 100,000 patients, excluding mortality (95% confidence interval: 912-1351).

CONCLUSIONS

Prevalence rates were similar to those obtained in international studies using the same diagnostic instrument and, given the significant between-centre variability found, it is recommended that mental health statistics be considered at small area level. Mental disorders, and especially mood disorders, are associated with very poor quality of life and higher scores on disability indexes than other common chronic conditions.