Emotional disorders in evolutionary perspective.

Understanding emotional disorders requires understanding the evolutionary origins and functions of normal emotions. They are special states, shaped by natural selection to adjust various aspects of the organism in ways that have tended to give a selective advantage in the face of the adaptive challenges characteristic of a particular kind of situation. They are designed to maximize reproductive success, not happiness. Negative emotions such as anxiety and low mood are not disorders, but, like the capacity for pain, evolved defences. Excessive anxiety or low mood is abnormal, but we will not have confidence about what is excessive until we understand their functions better than we do. Emotional disorders arise often from social emotions because of the conflicts inherent in social life, and because of the strategic advantages of demonstrating commitments to follow through on threats and promises. An evolutionary understanding of individuals in terms of their relationship strategies and the social emotions offers great promise for psychotherapists.