Cerebrospinal fluid acetylcholinesterase in neuropsychiatric disorders.

Acetylcholinesterase (AChE) was measured in the cerebrospinal fluid (CSF) of patients with a diagnosis of Huntington's disease, depression, schizophrenia, or mania and also in the CSF of normal subjects. No significant differences in CSF AChE were found between any diagnostic group and normal subjects. Furthermore, the administration of choline chloride, physostigmine, or probenecid did not significantly alter CSF AChE. No diurnal variation in CSF AChE activity was apparent. These findings, combined with the unclear relationship of brain AChE to CSF AChE, suggest that this measurement does not reflect the relative cholinergic underactivity presumed to exist in some neuropsychiatric conditions.