Psychiatric manifestations accompanying interferon therapy for patients with chronic hepatitis C: an overview of cases in Japan.

Thirty case reports published in Japan that refer to psychiatric symptoms accompanying interferon (IFN) therapy were examined. These papers covered a total of 49 cases. We categorized these 49 cases into 35 cases of mood disorder, 10 of delirium and four of psychotic disorder. The key findings of our study of these cases are as follows: (i) in total, 11 patients had psychiatric past histories: five patients in the mood disorders group were susceptible to the influence of social or psychological factors; (ii) whereas the symptoms of mood disorder or delirium appeared soon after IFN was administered, the symptoms of psychotic disorders appeared later. The patients with delirium displayed many neurological abnormalities, which were reduced by suspending IFN therapy. This suggests the neurological toxicity of IFN; (iii) the outcome of most patients was good; and (iv) we suspect that IFN-induced psychiatric symptoms other than delirium are connected with psychoneuroimmunological functions.