The Biochemistry of Affective Disorders

The title of this review would be regarded by some psychiatrists as provocative; they would relegate the biochemical concomitants of depression and mania to a secondary position and deny that biochemical changes have any place in the aetiology of these conditions. However, in my view, the weight of evidence, although it is by no means conclusive, suggests that biochemical changes are most important in the aetiology of affective disorders. A biochemical aetiology implies that there are certain biochemical changes in the brain which need to be restored to normal before the patient's clinical condition will improve. This does not deny that psychological and environmental events may precipitate and maintain the biochemical events which in turn lead to the affective disorder. The study of these biochemical events is clearly at too early a stage for speculations about the interrelationship between environmental and endogenous elements to be fruitful; this study must wait until the biochemical aetiology is clearer than at present.