For the first time, scientists from the Centre for Addiction and Mental Health (CAMH) have discovered epigenetic changes (chemical changes to a gene that do not alter the DNA sequence) in individuals with schizophrenia and bipolar disorder. The findings may be a significant step on the way to fully understanding major psychosis.

CAMH's Dr. Arturas Petronis studied 12,000 locations on the genome using an epigenomic profiling technology and found that approximately one in every two hundred of these genes showed an epigenetic difference in the brains of psychiatric patients. Significantly, these changes were noted on genes involved in neurotransmission (the exchange of chemical messages within the brain) and brain development.

It's possible that these epigenetic changes may be the missing link in understanding what causes an illness.

Boffins Investigate Schizophrenia Genes

A new study in the Proceedings of the Royal Society B tries to uncover why several genes with strong associations to schizophrenia have evolved rapidly thanks to positive selection during human evolution.

The international team of geneticists found a higher prevalence of positive selection on genes known to be associated with the disorder than a comparable control set of non-associated genes, functioning in similar neuronal processes. This is consistent with the theory that positive selection may play a role in the persistence of schizophrenia, despite its strong effects on reproductive fitness and its high heritability from generation-to-generation.



"The selective forces influencing the evolution of these [schizophrenia] genes remain unknown."

The researchers speculate that given the complex genetic nature of the condition, selection may be mediated by a diverse array of neural, physiological and psychological mechanisms. "Schizophrenia has also been associated with creativity throughout recorded history, but whether this link has a genetic basis is not yet clear," noted Dorus.