7 - ELECTROENCEPHALOGRAPHIC SLEEP CHANGES IN PSYCHIATRIC PATIENTS

Abstract

Electroencephalographic (EEG) sleep studies of patients with schizophrenic and affective disorders have yielded much information about the changes of sleep–wake function and organization during the acute phases of these disorders and, to a lesser extent, during periods of remission. Sleep disturbances in psychiatric disorders are complex and varied, ranging from profound hyposomnia to marked hypersomnia. The EEG sleep characteristics of various psychiatric disorders differ considerably, and these differences provide objective physiologic measures that are useful in differential diagnosis. A short rapid-eye-movement (REM) latency with increased amounts of REM time and activity in the first REM period is a most predictable and specific biological marker of primary depression. This finding holds promise for differentiating depressives from patients with generalized anxiety disorders or with schizophrenic disorders, with the exception of schizoaffective patients whose sleep appears very similar to that of delusional depressives. Diminished REM-sleep density is the hallmark of medical-depressive syndromes and, together with REM latency changes, holds promise for the differentiation of elderly patients with depression, depressive pseudodementia, and dementia. In addition, EEG sleep measures can be used to predict clinical response to psychopharmacologic intervention. For example, sleep disturbance in acutely ill schizophrenic patients is useful in titrating the dosage of neuroleptic therapy.