The hospital records of 46 schizophrenic patients were studied retrospectively for postpsychotic collapse (PPC), defined in terms of underactivity. PPC was observed in 38 (83%) patients. The duration of PPC was strongly correlated with the duration of the acute psychotic phase after therapy started, and weakly correlated with the mean dose of antipsychotics per day in the acute psychotic phase, and with age of onset. The authors discuss PPC in terms of the effect of antipsychotics, of psychological reaction, and of understimulation in the hospital setting.