Deviant olfactory experiences as indicators of risk for psychosis.

Olfactory hallucinations, although relatively rare, are reportedly indicative of serious psychopathology and poor prognosis in psychotic patients. This article describes the development of a rating scale for assessing olfactory experiences of psychotic and psychoticlike deviancy. The scale is modeled after Chapman and Chapman's rating scales for other psychoticlike experiences, which have been found to predict psychosis and psychosis-proneness. In a longitudinal study, college students who reported deviant olfactory experiences at their initial assessment (n = 31) exceeded the remaining subjects (n = 477) on DSM-III-R psychosis and on measures of psychosis proneness at a 10-year followup. Furthermore, hypothetically psychosis-prone subjects identified by the Perceptual Aberration and Magical Ideation scales exceeded control subjects on ratings of olfactory experiences at both initial and followup assessments.