[In] the thought-provoking Good Reasons for Bad Feelings, [evolutionary] psychiatrist Randolph Nesse offers insights that radically reframe psychiatric conditions.
In his view, the roots of mental illnesses, such as anxiety and depression, lie in essential functions that evolved as building blocks of adaptive behavioural and cognitive function. Furthermore, like the legs of thoroughbred racehorses — selected for length, but tending towards weakness — some dysfunctional aspects of mental function might have originated with selection for unrelated traits, such as cognitive capacity.
The future success of clinical psychiatry might depend on an evolutionary framework being integrated with whole-genome sequence-data analysis; this could help to identify mutations predisposing people to mental illness. Given the small contributions of individual genes and the diverse mechanisms involved, this will demand analysis of the genomes of hundreds of thousands of people. As a result of the extensive and often paradoxical entanglement of genetic networks, future treatments might, by necessity, require mental circuits to be engineered to release them from hard-wired evolutionary constraints.
As Good Reasons for Bad Feelings boldly posits, many of the core dysfunctional components of mental illness ultimately help to make us human.
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