While we previously detected anti-bornavirus antibodies via radioligand assay in psychiatric patients, we did not examine the viral pathogenicity in these individuals. Herein, we present 2 psychiatric patients who were seropositive for bornavirus and whose treatment-resistant symptoms improved after oral administration of ribavirin, a broad-spectrum antiviral agent. Cerebrospinal fluid analysis indicated that ribavirin affected the central nervous system of these patients. Ribavirin ameliorated intermittent involuntary head shaking, which is reminiscent of a symptom observed in bornavirus-infected animals. Using radioligand assays to examine the serial sera of these patients, we found a relationship between the titers of anti-bornavirus antibodies and the change in the patients’ symptoms. Our findings suggest there is a relationship between bornavirus infection and human symptoms and that ribavirin may be useful in suppressing chronic bornavirus infection in some neuropsychiatric patients. However, the possibility remains that some other known or unknown virus other than bornavirus that is sensitive to ribavirin may have caused the symptoms. Additional evidence that directly indicates the causative relationship between bornavirus infection and human symptoms is needed before establishing the pathogenesis and treatment for human bornavirus infection.