Could Infection Effect Cognitive Function in Schizophrenia ? : One Egyptian Center Study

Abstract

ackground: Numerous viral infections, in utero or in childhood, have been associated with an increased risk of later developing schizophrenia. This may be explained by chronic infections or an altered immune status. Objectives: The present study aimed to measure levels of serum antibodies to some infectious agents in a sample of Egyptian patients with schizophrenia and to assess if there is correlation of cognitive functioning with this serum titer. Methods: the Arabic Version of Wechsler Adult Intelligence Scale Revised; selected subtests from Wechsler Memory Scale-Revised; Trail making test and Self-Assessment Scale of Cognitive Complaints in Schizophrenia were used to assess cognitive function in 102 newly diagnosed drug naive patients with schizophrenia and 124 healthy matched individuals. Solid phase enzyme immuno-assay (EIA) techniques were used to measure IgG class antibodies to Rubella virus, cytomegalovirus (CMV), Herpes simplex virus type 1&2 (HSV-1&2), and to Toxoplasma gondii (T. gondii) in the sera of the study individuals. Associations between serological exposure to selected infectious agents and cognitive function in schizophrenia were evaluated. Results: All studied infectious agents were more prevalent in patients with schizophrenia than in the control group. Higher anti-HSV1&2, and anti-Rubella IgG antibodies titers were significantly correlated with impaired cognitive tests, while anti-T. gondii IgG titer was insignificantly correlated with any of the neuro-cognitive tests. Conclusions: The higher prevalence of serum IgG antibodies to all analyzed infectious agents with higher titers within patients with schizophrenia emphasizes a possible role of infectious agents in the etiopatho-genesis of schizophrenia. The data indicates that not one specific agent might be responsible for schizophrenic symptoms. Impairment of the cognitive functions in patients with schizophrenia was associated with higher IgG titers to HSV1&2, and Rubella virus.