The cholinergic system in schizophrenia reconsidered: Anticholinergic modulation of sleep and symptom profiles

The role of the cholinergic system in schizophrenia remains controversial. A series of investigations are reviewed that describe the effects of pharma cological manipulation of the cholinergic system on schizophrenia symptomat ology and whether putative measures of the cholinergic system are altered i n schizophrenia. The effects of biperiden (an anticholinergic agent) on pos itive and negative symptoms of schizophrenia and on vapid eye movement (REM ) latency and other sleep measures were assessed. Biperiden produced a sign ificant increase in positive symptoms and a decrease in negative symptoms. REM latency was significantly shorter in schizophrenic patients and increas ed in both groups following biperiden. REM density decreased in a dose-depe ndent manner following biperiden in schizophrenic patients, but not in norm al controls. The slope of REM density plotted against biperiden dose was in versely related to plasma homovanillic acid (HVA), an index of dopamine (DA ) activity, in schizophrenic patients. These results further implicate the cholinergic system in schizophrenia pathophysiology and suggest a role for DA-acetylcholine (ACh) interactions in the production of sleep abnormalitie s and expression of positive and negative symptoms in schizophrenia. [Neuro psychopharmacology 22:S189-S202, 1999] (C) 1999 American College of Neureop sychopharmacology. Published by Elsevier Science Inc.