Abstract: Approximately 200 million years ago, reptilian stress-regulating brain systems, that were primarily suited for fight and flight responses, further developed into more emotion driven, mammalian, stress response systems. Hominoids later integrated the –also mammalian - inhibitory stress-regulating neocortex, that further evolved in homo sapiens during the last 200 thousand years of stable hunting and gathering.
Since 10 thousand years ago, external stressors became exponentially more abstract and, therefore, more internalized and inescapable, whereas our stress regulating brain systems hardly changed for the population at large. However, natural and sexual selection during evolution and specialization in our eusocial society resulted in a normal distribution of stress regulation. In this, so-called, Gauss curve the majority of subjects can adequately cope with the rapidly changing environment, whereas the minority to the (extreme) right or left of this Gauss curve cannot and may develop an anxiety- or depressive disorder. Stress physiology of the noradrenergic- and cortisol system and pathological stress responses will be discussed, as well as related treatment intervention. Call it Evolution theory based therapy.
Keywords: Stress physiology, brain function, genetics, evolution theory based therapy, anxiety, depression
