We report on a 60-year-old woman with a history of bipolar mood disorder wh
o had seizures and developed a delirious state 1 week after the cessation o
f interferon-alpha (IFN-alpha) for chronic hepatitis C. The IFN-alpha was a
dministered to the patient for 7 weeks (266 million IU). One week after the
cessation of IFN-alpha therapy, the patient had four generalized tonic-clo
nic seizures over a 2-day period and developed a delirious state for 2 mont
hs. We consider these seizures and delirious state to be related to IFN-alp
ha.