Prognosis of depressive disorders in the general population- results from the longitudinal Finnish Health 2011 Study

Depressive disorders are among the most pressing public health challenges worldwide. Yet, not enough is known about their long-term outcomes. This study examines the course and predictors of different outcomes of depressive disorders in an eleven-year follow-up of a general population sample.

In a nationally representative sample of Finns aged 30 and over (BRIF8901), major depressive disorder (MDD) and dysthymia were diagnosed with the Composite International Diagnostic Interview (M-CIDI) in 2000. The participants were followed up in 2011 (n=5733). Outcome measures were diagnostic status, mortality, depressive symptoms and health-related quality of life. Multiple imputation (MI) was used to account for nonresponse.

At follow-up, 33.8% of persons with baseline MDD and 42.6% with baseline dysthymia received a diagnosis of depressive, anxiety or alcohol use disorder. Baseline severity of disorder, measured by the Beck Depression Inventory, predicted both persistence of depressive disorder and increased mortality risk. In addition, being never-married, separated or widowed predicted persistence of depressive disorders, whereas somatic and psychiatric comorbidity, childhood adversities and lower social capital did not. Those who received no psychiatric diagnosis at follow-up still had residual symptoms and lower quality of life.

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

Depressive disorders in the general population are associated with multiple negative outcomes. Severity of index episode is the strongest predictor of negative outcomes. More emphasis should be placed on addressing the long-term consequences of depression.