Evolution-based Approach to Understand and Classify Mental Disorders

Context: The present diagnostic manuals for mental disorders (DSM-5 and ICD10) rely primarily on traditional descriptive phenomenology; the use of objective, biological criteria (such as neurological or genetic correlates) has limited impact. Considering the human brain as a “box of tools” designed by the process of evolution offers an alternative framework. There are two main reasons for classifying a particular brain condition as a mental disorder: It entails either an unwarranted reduction in quality of life, or problems with functioning in society. In either case, the condition tends to have a correlate in the form of brain functions not operating according to the “intent” laid down in the evolutionary design. Objective: The present text reviews the evolutionary perspective on mental health and suggests features that may contribute to a novel nosology. The approach is based on an inventory of the various functions, or modules, evolution added to the brain for the purpose of survival and procreation. It focuses on major categories of disorders (that is, meta-structure), but combined they should accommodate presently recognized conditions. Conclusion: The evolutionary perspective offers insight that may inform diagnostics, or at least improve our conceptual grasp of mental conditions.