Abnormal Rapid Eye Movement Latencies in Schizophrenia

Several previous studies have observed short rapid eye movement (REM) latencies in schizophrenic patients without major affective disorder. This study was designed to meet several of the criticisms of those previous studies. Using Research Diagnostic Criteria, we compared the sleep patterns of schizophrenic patients with those of normal controls and patients with major depressive disorder and schizoaffective disorder. All patients were medication free, and REM latency was explicitly defined using both strict and lenient criteria. Chronically ill paranoid or undifferentiated schizophrenics could not be distinguished from patients with major depressive disorder or schizoaffective disorder using any definition of REM latency. These results were not due to longer REM latency in the particular sample of patients with major depressive disorder. They had abnormally low REM latencies; however, the schizophrenic patients showed similar decrements. These data cast serious doubt on the specificity of short REM latency as a biological marker for major depressive disorder.