ABSTRACT Background and Objectives: Psychiatric disorders such as schizophrenia and bipolar disorder pose a high burden among the general population. Etiological factor(s) of such disorders remain unknown. Borna disease virus (BDV) is a neurotropic virus that has been suggested as an etiological agent for psychiatric disorders. Therefore, we aimed to investigate the prevalence of BDV among patients with schizophrenia and bipolar disorder. Methods: Peripheral blood mononuclear cells (PBMCs) of schizophrenic (n=75) and bipolar (n=55) patients and healthy blood donors (n=125) were extracted form whole blood samples. RNA was extracted from PBMCs and the presence of BDV P40 RNA was assessed by reverse transcription-polymerase chain reaction. Results: The BDV genome was not detected in any of the subjects. Positive family history of disease was significantly more frequent among patients (P=0.0001). There was a significant association between contact with animals and psychiatric illnesses (P
