Toxoplasma gondii exposure in patients suffering from mental and behavioral disorders due to psychoactive substance use

Background: Toxoplasma gondii infection has been associated with psychiatric diseases. However, there is no information about the link between this infection and patients with mental and behavioral disorders due to psychoactive substance use. Methods: We performed a case-control study with 149 psychiatric patients suffering from mental and behavioral disorders due to psychoactive substance use and 149 age- and gender-matched control subjects of the general population. We searched for anti-T. gondii IgG and IgM antibodies in the sera of participants by means of commercially available enzyme-linked immunoassays. Seroprevalence association with socio-demographic, clinical and behavioral characteristics in psychiatric patients was also investigated. Results: Anti-T. gondii IgG antibodies were present in 15 (10.1%) of 149 cases and in 14 (9.4%) of 149 controls (P = 1.0). Anti-T. gondii IgM antibodies were found in 11 (7.4%) of the 149 cases and in 16 (10.7%) of the 149 controls (P = 0.31). No association of T. gondii exposure with socio-demographic characteristics of patients was found. Multivariate analysis of clinical and behavioral characteristics of cases showed that T. gondii seropositivity was positively associated with consumption of opossum meat (OR = 10.78; 95% CI: 2.16-53.81; P = 0.003) and soil flooring at home (OR = 11.15; 95% CI: 1.58-78.92; P = 0.01), and negatively associated with suicidal ideation (OR = 0.17; 95% CI: 0.05-0.64; P = 0.008). Conclusions: Mental and behavioral disorders due to psychoactive substance use do not appear to represent an increased risk for T. gondii exposure. This is the first report of a positive association of T. gondii exposure with consumption of opossum meat. Further studies to elucidate the role of T. gondii infection in suicidal ideation and behavior are needed to develop optimal strategies for the prevention of infection with T. gondii.