A German Multicenter Study on Toxoplasma Gondii in First-episode Schizophrenia

Environmental risk factors for the development of schizophrenia include infections during the perinatal period or later in life with Toxoplasma gondii (TG) being one of the candidate agents. A recent review (Torrey and Yolken, 2003) on TG in schizophrenia and other serious mental disorder reported higher antibodies to TG in patients compared to controls in 18 of 19 studies, one having been conducted by the investigators group. In a second, independent study on first-episode schizophrenia (n=56) and control subjects (n=32), sera were sampled and standard instruments used to assess diagnoses and psychopathology, respectively to screening controls.

For the total sample, contacts with animals during pregnancy and age emerged as a non-significant predictors of TG IgG titers. Means of patients' and controls' TG IgG titers did not differ significantly but variances did; a subgroup of patients' titers reached much higher levels than those of controls. Patients in the high TG IgG subgroup were older (p=0.001), also they were older when psychiatric symptoms appeared, more individuals had regular animal contacts during pregnancy, or rural upbringing including regular animal contact, more consumption of raw meat, and a higher absolute treatment response (all trend levels). Regarding the short term course of patients, the investigators detected decreasing IgG titers in several individuals A power analysis demonstrated that results fell short of significance due to lack of statistical power. Based on the power analysis, the investigators propose an opel label, multicenter study at three regionally different sites within Germany (Halle, Hamm, Heidelberg). The investigators intent to study 173 first-episode patients with schizophrenia, schizoaffective, and schizophreniform disorder and 173 matched controls.

The investigators hypothesize that - according to the heterogeneity of the illness - a subgroup of patients will exhibit higher TG IgG titers compared to the remaining patients and to controls; that this subgroup will have had regular contact with animals during pregnancy and early life as well as developmental delays; and that clinical improvement, response to treatment, and subjective well-being will run parallel with TG IgG decrease.

Patients shall be assessed on admission to hospital, at discharge and at 6- and 12-month-follow-up with respect to TG antibody titers, symptomatology, neuropsychology, predictors of outcome, quality of life, and neurological soft signs. In controls two assessments shall be performed, 12 months apart. All foreseen assessments will be performed using standard measurement instruments with sound reliability and validity such as the SCID and the PANSS. Exposure to cats, other warm-blooded life-stock, and raw meat will be assessed using a special questionnaire.