Schizophrenia Genes Favoured by Natural Selection

Author:  Metcalfe David
Date:  December 2007

Schizophrenia is commonly known as one of the most horrific mental illnesses, but new research has suggested that it is also the inevitable outcome of human creativity. According to data published in Proceedings of the Royal Society B earlier this month, genes which predispose to schizophrenia may have been favoured by natural selection. Lead author Bernard Crespi, professor of evolutionary biology at Simon Fraser University in Canada, and his colleagues concluded that "schizophrenia represents, in part, a maladaptive by-product of adaptive changes during human evolution".

The researchers explored the molecular evolution of 76 genes implicated in schizophrenia, and found 28 of these to have been positively selected during human evolution. Further evidence for this comes from the observation that schizophrenia occurs at a constant prevalence of 1% across all cultures worldwide. This is counter-intuitive given that onset of this disease seems likely to reduce the chances of reproduction.

According to one theory, these genes may underlie the human characteristic of creativity and only lead to schizophrenia in a minority of individuals. However, psychiatrist Raj Persaud counsels caution about uncritically accepting this theory. As Persaud told the Telegraph, "people with schizophrenia think in ways that are unexpected and surprising which may explain the link to creativity. but the problem with this theory is that the creation of culturally useful products – as opposed to just nonsense – also requires deployment of analytical and critical judgement. not just novel ideas." Although Crespi and his colleagues have shown that natural selection has positively selected for some genes associated with schizophrenia, the creativity theory remains unproven.

Written by David Metcalfe

Reviewed by Frances Mao

Published by Pooja Ghatalia.