A history of metaphorical brain talk in psychiatry.

From the very beginnings of our field in the late 18th century, psychiatrists have engaged, often extensively, in "metaphorical brain talk" - rephrasing descriptions of mental processes in unconfirmed brain metaphors (e.g., "diseased working of the brain convolutions"). In the late 19th century, Kraepelin criticized the later developments of such approaches, termed "brain mythology" by the philosopher/psychiatrist Jaspers in 1913. In this essay, I review the history, meaning, and significance of this phenomenon and reach four conclusions. First, this trend has continued to the present day in metaphors such as the "broken brain" and the use of simplistic and empirically poorly supported explanations of psychiatric illness, such as depression being "due to an imbalance of serotonin in the brain." Second, our language stems from the tension in our profession that seeks to be a part of medicine yet declares our main focus as treatment of the mental. We feel more comfortable with the reductionist approach of brain metaphors, which, even though at times self-deceptive, reinforce our commitment to and membership in a brain-based medical specialty. Third, metaphorical brain talk can also be seen as the "promissory note" of our profession, a pledge that the day will come when we can indeed explain accurately to ourselves and to our patients the brain basis of the psychiatric disorders from which they suffer. Finally, moving away from metaphorical brain talk would reflect an increasing maturity of both the research and clinical aspects of our profession.