Effects of ketamine in normal and schizophrenic volunteers.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology October 1, 2001 A C Lahti, M A Weiler, B A Tamara Michaelidis et al.
Ketamine produces a short-lived (<30 minutes) increase in psychotic symptoms in both healthy volunteers and people with schizophrenia, with the magnitude of positive-symptom change similar across groups despite different baselines. In healthy volunteers, ketamine raised scores on both the psychosis and withdrawal subscales of the Brief Psychiatric Rating Scale, whereas in schizophrenic volunteers only positive symptoms increased. Seventy percent of patients reported an exacerbation of previously experienced positive symptoms. The similarity between ketamine-induced symptoms and patients' own positive symptoms suggests ketamine offers a unique human psychosis model, potentially more valid than the amphetamine model for studying schizophrenia.