A slow wave sleep (SWS) deficit and a shortened rapid eye movement (REM) sleep latency are commonly reported in schizophrenic patients. However, most of these patients have been off neuroleptic medication for only a short period of time. Therefore, the reported sleep alterations may be due to residual drug effects. We polysomnographically investigated 22 drug-naive patients with a schizophrenic disorder, paranoid type, and 20 normal controls. In addition, we assessed the ventricular brain ratio (VBR) by means of computed assisted tomography. Except for a prolonged sleep onset latency, increased wake time and decreased stage 2 sleep, the patients showed a sleep pattern, i.e., of SWS and REM sleep, comparable with that of controls. The VBR was increased in 71% of the patients but was not associated with the patients' clinical characteristics or their SWS and REM sleep patterns. Our results indicate that the commonly reported SWS and REM sleep changes in schizophrenia reflect the remnant of prior neuroleptic treatment rather than the pathophysiology of the disorder itself.