Toxoplasmosis in psychiatric disorders: immunologic and epidemiologic findings

There are several reports that individuals with schizophrenia compared to healthy controls have increased prevalence of Toxoplasma gondii (Tg), a chronic neurotropic parasitic infection modulating relevant neurotransmitter systems. Thus, we investigated whether this is specific to schizophrenia and whether this infection impacts in first episodes or later during the disorder. Specific serology and in vitro investigations on peripheral blood cells were performed in individuals with schizophrenia, bipolar, depressive or personality disorders and in healthy controls. At 2003-AGNP meeting, we presented preliminary results, now we will present final results.

We took serology samples from 1262 individuals and did cellular analyses in 205 individuals. Thus, we comprise the largest and most differentiated -by means of psychiatric diagnoses– controlled prospectively collected sample. Pending the complex statistical analysis, already our data do not favor a higher frequency of Tg infection solely in schizophrenia nor during the first episode. Factors such as chronicity of the disorders, age, route of infection and intensity of the immune response play a role. Moreover, this infection might contribute to distinctly impaired cognitive and mental functioning rather than to a specific psychiatric diagnosis. Our results will detail this.

The study is supported by a grant of the Stanley Medical Research Institute