[Confusion and delusions occurring during interferon-alpha treatment].

A number of side effects occurring during IFN therapy have been described. Psychiatric side effects include cognitive, behavioural and affective changes, confusion and, less commonly, psychotic symptoms. We report the case of a 52-year-old patient who had been treated for almost three years with IFN alpha for a chronic myelogenous leukemia and who presented an acute confusional episode with delusions, following the reintroduction of IFN alpha after a therapy suspension of 2 weeks. Clinical improvement occurred quite rapidly after cessation of the IFN treatment; this evolution and the normality of the biological tests, EEG and cerebral imagery suggest a causal relationship between this treatment and the psychiatric symptoms.