Toxoplasma gondii Seroprevalence and Associated Risk Factors in Psychiatric Patients Diagnosed with Moderate and...

The protozoan parasite Toxoplasma gondii (T. gondii) has been implicated in various neuropsychiatric disorders, including depression. Our aim in this study was to assess the seroprevalence of T. gondii IgG antibodies as well as potential risk factors associated with seropositivity in patients with depression compared to healthy blood donors. This seroepidemiological study included 230 participants from Western Romania, divided equally into two groups: 115 patients diagnosed with depressive disorders which represented the study group and 115 age and gender-matched healthy blood donors, representing the control group. A structured questionnaire was used to assess risk factors potentially linked to T. gondii infection. The T. gondii IgG antibodies overall seroprevalence was significantly higher in the depression group (70.43%) compared to the control group (45.22%) (OR = 2.89; 95% CI: 1.68-4.97; p < 0.001). Higher seropositivity was noted in patients aged 50-59, 60+ years and in females. Patients with lower educational attainment showed significantly increased odds of T. gondii seropositivity (72.29% vs. 44.3%, OR = 3.28; 95% CI: 1.71-6.31; p < 0.001) compared with the control group. Stratification by ICD-10 diagnostic subtypes revealed significantly higher seropositivity in all categories, with the strongest association in patients with recurrent severe depressive episodes without psychotic symptoms (F33.2) (81.25%, OR = 3.5; 95% CI: 1.51-8.13; p = 0.004). These findings suggest a possible link between T. gondii infection and depression, particularly in relation to disease severity and sociodemographic factors. To our knowledge, this is the first study to investigate T. gondii seroprevalence and associated risk factors in Romanian patients with depression, providing a foundation for future longitudinal and preventive research.