OBJECTIVES: Toxoplasma gondii, the protozoan parasite infecting about 30% population worldwide, is suspected to be the etiological agent of certain form of schizophrenia disease. Toxoplasma is known to change levels of certain neurotransmitters, cytokines and several hormones in both infected animals and humans. A common feature of toxoplasmosis and schizophrenia is a disorder of immune system.
METHODS: Here we studied the levels of five neuro- and immunomodulatory steroids, selected hormones and lipids in sera of 173 schizophrenia patients.
RESULTS: Toxoplasma infected schizophrenia patients expressed only insignificantly lower concentration of neuro- and immunomodulatory DHEA metabolites. Infected women had higher concentration of glucose while infected men had higher concentration of cholesterol and LDL cholesterol. No significant effect of human cytomegalovirus infection on the concentration of the above parameters was observed. The difference in the concentration of DHEA metabolites faded with the decrease of the concentration of anti-Toxoplasma IgG antibodies (i.e. with the duration of Toxoplasma infection) while the difference in the concentration of cholesterol and LDL-cholesterol increased with the decrease of the concentration of anti-Toxoplasma IgG antibodies. The prevalence of toxoplasmosis in male (53.2%) but not female (29.8%) schizophrenia patients was unusually high in comparison with prevalence of toxoplasmosis in a general population.
CONCLUSION: Our results provided an explanation for seemingly decreasing prevalence of toxoplasmosis in schizophrenia patients observed in current studies (increased concerns about the rights of patients resulting in absence of non-cooperative Toxoplasma-positive patients in the study population) and suggest possible explanation for reported positive correlation between prevalence of toxoplasmosis and incidence of cardiovascular diseases (accelerated atherosclerotic development due to increased level of cholesterol and LDL in Toxoplasma infected humans).