1959

Everett and Toman offer one of first explicit statements that the level of biogenic amine activity determines mood: “they were among the earliest to propose that depression was caused by a deficiency and mania from an excess in biogenic amine activity. The biogenic amine theory relied heavily on the fact that the effectiveness of drugs to alleviate either spontaneously occurring depression or what was called ‘reserpine-induced depression’ seemed to be determined by their capacity to elevate biogenic amines” (Valenstein, 72). “Despite the wide promotion of the biogenic amine deficiency theory of depression, most researchers working in the field recognize its inadequacy and are trying to come up with alternative theories. . . . our theories have changed very little in the past fifty years. . . most of the biochemical research on emotional states is concerned with at most three or four [norepinephrine, serotonin, dopamine] of the over one hundred neurotransmitters now estimated to be present in the brain. Moreover, the newest antidepressant drugs still act only on the same two or three neurotransmitters, although the receptor targets are more specific. Drug development is driven more by market considerations than by any clearer understanding of what causes depression or how drugs sometimes alleviate this condition” (Valenstein, 109-110).