Toxoplasma gondii infection and common mental disorders in the Finnish general population.

OBJECTIVE: We investigated whether T. gondii seropositivity is associated with 12-month depressive, anxiety and alcohol use disorders and current depressive symptoms and whether inflammation, measured by C-reactive protein (CRP) level, explains these associations. METHOD: Health 2000 study (BRIF8901), conducted in years 2000-2001, is based on a nationally representative sample of Finns aged 30 and above, with 7112 participants and 88.6% response rate. DSM-IV depressive, anxiety and alcohol use disorders were assessed with the Composite International Diagnostic Interview and depressive symptoms with the Beck Depressive Inventory (BDI-21). We used logistic regression to investigate the association of T. gondii seropositivity with mental disorders and linear regression with BDI-21 scores. RESULTS: T. gondii seroprevalence was significantly associated with 12-month generalized anxiety disorder but not with other anxiety, depressive or alcohol use disorders. T. gondii seropositivity was associated with higher BDI-21 scores (beta 0.56, 95% CI 0.12-1.00, P = 0.013) and with having a comorbid depressive and anxiety disorder (OR 1.86, 95% CI 1.16-2.97, P = 0.010). Higher CRP levels were associated with these outcomes and with T. gondii seropositivity, but adjusting for CRP did not change the effect of T. gondii seropositivity. LIMITATIONS: Cross-sectional study design with no information on the timing of T. gondii infection. CONCLUSION: T. gondii seropositivity is associated with generalized anxiety disorder, depressive symptoms and comorbid depressive and anxiety disorders, which is not mediated by inflammation.