A Canadian study has suggested that the brains of suicidal people were chemically different to those who die from other causes.

After analyzing brain tissue of 20 dead people, 10 who committed suicide and 10 who died of other causes, the researchers found a higher rate of a process that affects behaviour in the suicidal ones. They believe that environmental factors played a part in the changes.

They found that the DNA in the suicide group was being chemically modified by a process normally involved in regulating cell development, called methylation. It is methylation which shuts down the unwanted genes in a cell - so the necessary genes are expressed to make a cell a skin cell rather than, for example, a heart cell.

The presence of methylation in the suicide brains was almost 10 times that of the other group, and the gene that was being shut down was a chemical message receptor that plays a major role in regulating behaviour.
Researchers believe that this reprogramming could contribute to the "protracted and recurrent nature of major depressive disorder".
Previous research have shown that changes to the methylation process can be caused by a combination of genetic and environmental factors called epigenetics.

The researchers say that the whole idea that the genome is so easily infleunced in the brain is surprising, because brain cells don't divide. Neurons get dealth at the start of life, so the idea that there are still epigenetic mechanisms going on is pretty unusual.

The editor of Biological Psychiatry, John Krystal, is excited about the new evidence that genetic and environmental factors may interact to produce specific and long-lasting modifications in brain circuits that may further shape the course of one's life in extremely important ways such as increasing the risk for major depressive disorder and perhaps suicide.
These findings opened up a new avenue of research and potential therapies for depression and suicidal tendencies.