Seropositivity of neurotropic infectious agents in first-episode schizophrenia patients and the relationship with positive and negative symptoms.

BACKGROUND: According to the neurodevelopmental model, schizophrenia is a disorder that occurs as a result of different etiologic factors during brain development, including viral infections. However, it is unclear whether these infections are related to the disease or whether they affect the symptom pattern. We investigated the presence of four herpes viruses (EBV, CMV, HSV-1 and HSV-2) in first-episode schizophrenia patients and compared seropositive with seronegative patients and healthy volunteers to reveal the etiological role of viral agents on schizophrenia symptoms. SUBJECTS AND METHODS: Ninety-two first-episode patients who met the DSM-IV diagnostic criteria for schizophreniform disorder were included the study, along with 88 healthy volunteers. The presence of the four herpes viruses was investigated with serological methods (ELISA) in both groups. Positive and negative symptoms were evaluated with Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS).
RESULTS: There was no difference between the patient and control groups in terms of seropositivity of the four viruses. We found that SANS scores of HSV-1 and CMV seropositive schizophrenia patients were significantly higher than the scores of patients with seronegative schizophrenia. No difference was found in SAPS scores.
CONCLUSIONS: The results suggest a role of HSV and CMV infections in negative symptoms. This supports the hypothesis that viruses do not directly give rise to schizophrenia, but patients who were previously been infected with these viral agents may be prone to schizophrenia, and some of the symptom patterns may be related to different agents.