Predictors of new-onset depressive disorders - Results from the longitudinal Finnish Health 2011 Study.

BACKGROUND

Identifying risk factors for depression is important for understanding etiological mechanisms and targeting preventive efforts. No prior studies have compared risk factors of dysthymia and major depressive disorder (MDD) in a longitudinal setting.

METHODS

Predictors of new-onset MDD and dysthymia were examined in a longitudinal general population study (Health 2000 and 2011 Surveys, BRIF8901). 4057 persons free of depressive disorders at baseline were followed up for 11 years. DSM-IV MDD and dysthymia were diagnosed with the Composite International Diagnostic Interview.

RESULTS

126 persons (4.4%, 95%CI 3.6-5.2) were diagnosed with MDD or dysthymia at follow-up. Predictors of new-onset depressive disorders were younger age (adjusted OR 0.97, 95%CI 0.95-0.99 per year), female gender (aOR 1.46, 95%CI 1.01-2.12), multiple childhood adversities (aOR 1.76, 95%CI 1.10-2.83), low trust dimension of social capital (aOR 0.58, 95%CI 0.36-0.96 for high trust), baseline anxiety disorder (aOR 2.75, 95%CI 1.36-5.56), and baseline depressive symptoms (aOR 1.65, 95%CI 1.04-2.61 for moderate and aOR 2.49, 95%CI 1.20-5.17 for severe symptoms). Risk factors for MDD were younger age, female gender, anxiety disorder and depressive symptoms, whereas younger age, multiple childhood adversities, low trust, and having 1-2 somatic diseases predicted dysthymia.

LIMITATIONS: We only had one follow-up point at eleven years, and did not collect information on the subjects' health during the follow-up period.

CONCLUSIONS

Persons with subclinical depressive symptoms, anxiety disorders, low trust, and multiple childhood adversities have a higher risk of depressive disorders. Predictors of MDD and dysthymia appear to differ. This information can be used to target preventive efforts and guide social policies.