SYNOPSIS
Monoamines have been associated with affective disorders following observations with mood elevating and mood depressing drugs. In addition, abnormalities in the metabolism of the biogenic amines have been reported in these illnesses. Experimental studies on animals have further supported the view that both catecholamines and indoleamines are important for the maintenance of normal mood states. The monoamine hypothesis of affective disorders states that severe depression is associated with a relative deficiency of brain monoamines, while clinical improvement follows correction of this deficit. The converse applies to mania and antimanic treatments. The evidence for these assertions is critically examined, and pertinent experimental observations will be discussed. The monoamine hypotheses of Brodie and of Dewhurst are examined to integrate the findings reported, and the biogenic amines will be shown to be only part of a more complex biochemical disturbance involving the hypothalamic-pituitary-adrenocortical system.