Socio-economic position and mental disorders in a working-age Finnish population: the health 2000 study.

BACKGROUND: Mental disorders are more common in people with lower socio-economic position (SEP) but it is not known which specific SEP component is most strongly linked to poor mental health. We compared the strength of associations of three SEP components-occupation, income and education-with common mental disorders in a Finnish population.
METHODS: Cross-sectional analysis of a nationally representative sample of 4561 men and women aged 30-65 years. Mental disorders were assessed using the Composite International Diagnostic Interview resulting in 12-month DSM-IV diagnoses of depressive, anxiety and alcohol use disorders. Participants were classified as having low SEP if they worked in a manual occupation, lacked secondary-level education or had income below the Organisation for Economic Co-operation and Development (OECD) definition of relative poverty.
RESULTS: In models comparing the simultaneous association of all three socio-economic indicators with mental disorders, low income was associated with increased risk for depressive disorder [odds ratio (OR)=1.73, 95% confidence interval (CI) =1.31-2.29] and anxiety disorder (OR=1.56, 95% CI 1.14-2.12). Manual occupational class was modestly associated with risk for alcohol use disorder (OR=1.44, 95% CI 1.06-1.95). Low income was the only socio-economic component associated with psychiatric comorbidity, that is, a combination of various disorders within the same individual (OR 2.26, 95% CI 1.52-3.37 for any combination).
CONCLUSION: Low income seems to be a more important correlate of mental disorders than education or occupation in a high-income country such as Finland.