News > Brain asymmetry and psychosis

Created: 2007-08-01 14:45:17

For over 20 years Professor Tim Crow, honorary director of POWIC, has been convinced that handedness - the propensity of 90 per cent of the population to use their right hands for most manual task - relects an asymmetry in the brain that has a genetic basis relevant to the predisposition to psychosis.

Here he discusses the recent claim, by scientists at Oxford University, to have identified a gene that increases both the chances of being left-handed and of developing schizophrenia.

"The identification of the gene responsible for schizophrenia, and its mode of action, is a high priority for progress in the field of psychosis research, and SANE welcomes any research to this end.

"However I have considerable doubts that the authors of the research, Dr Francks et al, have identified such a gene.

"It is well established that males are more likely to be left-handed that females. This suggests a role for the sex chromosones and indeed there is good evidence that handedness and cerebral asymmetry are sex linked.

"The authors, who claim to have found the gene, ignored a paper published in 2006 presenting evidence for a gene-pair (Protocadherin XY) that is present on both the X and Y chromosones. This gene by contrast with the one they have focused on has been subject to rapid change in hominid evolution. It appears a much better candidate for the evolution of language and human characteristics that the one they describe.

"Their paper is a reflection of the present state of confusion in the field of genetic research in psychosis. There has been much emphasis on the linkage strategy that now seems to have failed.

"A new, much more common sense approach is required. What is known about the symptoms, the brain changes and sex differences in psychosis need to be take account of. Similarly what is already known about handedness and its cerebral basis must be considered. More and intensive research on this topic is highly desirable."

For more information about the research being undertaken visit the POWIC page.