Schizophrenia & the Limits of Rational Thought

"Many people have noticed that schizophrenics seem to appear in successful and intelligent families. People with a mild version of the disorder, as noted earlier, these are sometimes called "schizotypal" people - are often unusually brilliant, self-assured, and focused.

...One absurdly precise study estimates that 28 percent of prominent scientists, 60 percent of composers, 73 percent of painters, 77 percent of novelists, and an astonishing 87 percent of poets have shown some degree of mental disturbance.

As John Nash, the Princeton mathematician, said after recovering from 30 years of schizophrenia and accepting a Nobel Prize for his work on game theory, the interludes of rationality between his psychotic episodes were not welcome at all. "Rational thought imposes a limit on a person's concept of his relation to the cosmos."

The psychiatrist Randolph Nesse of Michigan speculates that schizophrenia may be an example of an evolutionary "cliff effect", in which the mutations in different genes are all beneficial, except when they all come together in one person, or evolve just too far, at which point they suddenly combine to produce a disaster.

Perhaps schizophrenia is the result of too much of a good thing: too many genetic and environmental factors that are usually good for brain function all coming together in one individual. This would explain why the genes predisposing people to schizophrenia do not die out; so long as they do not combine, they each benefit the survival of the carrier."

Page 122, 'The Agile Gene, How Nature turns on Nurture' by Matt Ridley, author of 'Genome'