Relationship between Toxoplasma gondii seropositivity and depression in children and adolescents

•We found that the T. gondii IgG seropositivity of depression group was higher than the healthy controls.•We evaluated T. gondii IgG antibody levels of depression group based on suicide attempt and suicidal ideation and found higher antibody levels in patients with suicide attempt and also with suicidal ideation.•The positive correlation in our study can be attributed to age.•The relationship of psychiatric disorders with either toxoplasma or some viral diseases has been revealed.•Detailed studies about the course of psychiatric disorders and treatment of infection in reactivation episodes and infection screening during psychiatric disorders are required. Identification of the structural causes of depression is important for the treatment process, and toxoplasmosis may be related to psychiatric disorders. The aim of this study was to evaluate the relationship between Toxoplasma gondii (T. gondii) seropositivity and depression in children and adolescents. This case-control study included 37 children and adolescents aged 11–18 years diagnosed with depression who were followed by the Manisa Celal Bayar University Child and Adolescent Mental Health Service and 36 children and adolescents aged 11–18 years with no history of depressive episodes or psychiatric disorder treated by the Pediatric Outpatient Department. The T. gondii serology of these two groups was evaluated and compared. There were no statistically significant age or sex differences between the 37 participants with depression and the 36 healthy controls. Eight patients and two controls were seropositive for T. gondii, a statistically significant difference (p = 0.046). Seropositivity was significantly higher in patients with suicidal ideation (p = 0.005) than in those without suicidal ideation. The seropositivity of seven of the nine participants who attempted suicide was significantly higher (p