Abstract

Some drugs which lower the concentration of amines in brain may produce depressive symptoms in man. An example of such a drug is reserpine which has been shown to lower the concentration of 5-hydroxytryptamine (5HT) in the brain.¹ Recent studies of depressive illnesses suggest that, in some depressed patients, the cerebral content of 5HT (as reflected by CSF metabolites) is low, probably due more to a low rate of synthesis² than to increased degradation.³ If reduced brain-5HT is a contributory factor in some depressive illnesses, restoring normal concentrations by promoting synthesis or reducing degradation should ameliorate the illness. However, evidence inconsistent with this hypothesis already exists.⁴ Furthermore, lack of detailed knowledge of the function of 5HT in the neurones which contain it makes accurate prediction from the animal laboratory to the psychiatric clinic difficult.