Evolution and revolution in child psychiatry: ADHD as a disorder of adaptation.

Current knowledge about early plasticity and children's responsiveness to environmental modifications as well as the atheoretical nature of current nosological systems necessitate alternative models to explain the phenomena of childhood behavioral and emotional disturbances. Evolutionary biology provides one such framework. It organizes data from the behavioral and cognitive sciences and parallels similar efforts in other areas of medicine and biology. Through an evolutionary biological lens, some mental disorders are better viewed as an adaptive response to early pathogenic environments and/or reflect the optimization of brain function to some environments at the cost of poorer response to the demands of other environments. As an example, the authors examine attention-deficit/hyperactivity disorder (ADHD) in relation to evolutionary theories of psychology and biology and clarify the potentially adaptive nature of characteristics of inattention, impulsivity, and motoric hyperactivity, depending on the nature of child's environments. Reframing ADHD characteristics according to evolutionary theory has important treatment implications for clinicians and offers researchers opportunities for novel scientific discoveries.