OBJECTIVES AND BACKGROUND Toxoplasma gondii infection has been recently associated with schizophrenia and other psychiatric disorders. The aim of the present study was to evaluate the prevalence of T. gondii infection in psychiatric patients by using meta-analytical methods. MATERIALS AND METHODS By systematic research of PUBMED Database, we identified several articles on this issue. We included casecontrol studies focused on the seroprevalence of T. gondii (IgG antibodies) in patients with psychiatric disorders and healthy controls, published over the past 10 years R3.2.2. free software for statistical computing and graphics was used to perform the meta-analysis. Data were pooled using a random effects model and Mantel-Haenszel method. RESULTS The PUBMED Database showed references to only seven scientific papers that investigated the prevalence of T. gondii IgG antibodies in psychiatric patients. Six hundred seventy three patients and seven hundred seventy four controls coped with the inclusion criteria and were used in our analysis. We found a significant increase of T. gondii IgG antibodies in patients with schizophrenia and other psychiatric disorders compared with controls (41.6% vs 24.54%, OR = 2.16, 95% CI = [1.45-3.21], P = .001). CONCLUSIONS An increased seroprevalence of T. gondii IgG antibodies has been reported in psychiatric patients. Our study suggests that T. gondii infection may be relevant in order to determine and understand the complex etiology of schizophrenia and other psychiatric disorders. Graphical abstract: Meta-analysis of the prevalence of T. gondii IgG antibodies in patients with mental disorders REFERENCES 1. Hamidinejat H, Ghorbanpoor M, Hosseini H, Alavi SM, Nabavi L, Jalali MH, Borojeni MP, Jafari H, Mohammadaligol S. Toxoplasma gondii infection in first-episode and inpatient individuals with schizophrenia. Int J Infect Dis. 2010;14:e978-81. doi: 10.1016/j.ijid.2010.05.018. 2. Alvarado-Esquivel C, Carrillo-Oropeza D, Pacheco-Vega SJ, Hernández-Tinoco J, SalcedoJaquez M, Sánchez-Anguiano LF, Ortiz-Jurado MN, Alarcón-Alvarado Y, Liesenfeld O, Beristain-García I. Toxoplasma gondii exposure in patients suffering from mental and behavioral disorders due to psychoactive substance use. BMC Infect Dis. 2015;15:172.