Increased Herpes simplex virus 1, Toxoplasma gondii and Cytomegalovirus antibody concentrations in severe mental illness

Infections with Cytomegalovirus (CMV), Herpes simplex virus 1 (HSV1) and Toxoplasma gondii (TG) have been implicated in severe mental illness. All three pathogens have high seroprevalence in the human population, are neurotropic and establish a persistent infection. We hypothesized that exposed (seropositive) patients with severe mental illness would show higher immunoglobulin G (IgG) concentrations than exposed healthy controls (HC). We included 765 patients with severe mental illness (schizophrenia n = 515, bipolar disorder n = 250) and 541 HC. CMV, HSV1 and TG IgG seropositivity and concentrations were measured with immunoassays (seropositivity: CMV, n = 447 patients vs. 296 HC; HSV1, n = 355 vs. 238; and TG, n = 159 vs. 126). Among seropositive participants, patients had higher HSV1 (p