Reflection of central aminergic-cholinergic imbalance by peripheral enzymes in psychiatric disorders?

Disturbances of central catecholaminergic-cholinergic balances have been discussed as causing affective disorders and schizophrenia. Such imbalances might be due to abnormalities of the metabolizing enzymes, especially their activities relative to each other. With this in mind, the activities of platelet monoamine oxidase and plasma butyrylcholinesterase (pseudocholinesterase) were determined spectrophotometrically in 33 psychiatric patients and eight controls. No significant differences could be detected for the enzyme activities as such and their relationship as expressed by their ratios. Thus, these peripheral enzymes seem to be unlikely indicators of supposed central imbalances.