An ingenious exploration of how Darwinian evolution explains mental disorders.
Psychiatrist Nesse (co-author: Why We Get Sick: The New Science of Darwinian Medicine, 1995, etc.), the founding director of the Center for Evolution and Medicine of Arizona State University, points out that even though successful organisms are well-adapted to their environments, all suffer disease. Diseases are not adaptations, but the traits that lead to them can be explained. Indeed, there are “good evolutionary reasons why we have desires we cannot fulfill, impulses we cannot control, and relationships full of conflict.” Nesse points out his specialty’s core dilemma. While physicians have long frowned on treating symptoms (pain, fatigue, sadness) as diseases, psychiatry hasn’t gotten the message. Provided depression or anxiety is intense, it becomes a disorder to be treated, regardless of the patient’s life situation. Yet unpleasant feelings, no less than physical discomfort, represent useful evolutionary responses. “Natural selection does not give a fig for our happiness,” writes the author. “In the calculus of evolution, only reproductive success matters.” Thus, anxiety is useful for dealing with threats of all kinds—debts, deadlines, oncoming cars, etc. A human with a lack of anxiety will be eliminated from the gene pool by getting killed or jailed, but on the other hand, someone consumed with anxiety has little sex appeal. Depression may not be the consequence of a disordered brain but rather a normal response to an unreachable goal. Many of us have more of certain feelings than we need, but instead of assuming that a pleasant emotion is good and a painful emotion bad, evolutionary psychiatry evaluates its appropriateness to the situation. Readers searching for an attack on psychiatry or a formula for achieving happiness have an avalanche of choices, but they will not regret choosing this book, which is neither.
Understanding phenomena has worked wonders in traditional medicine, and Nesse makes an appealing, convincing argument that psychiatrists who recognize the evolutionary function of emotions will find greater success.