Depression and Suicide Linked

The recent death of writer Sylvia Plath's son has prompted many news agencies to write about the growing evidence of a genetic cause for depression.

Several studies have shown that suicide rates (and therefore presumably depression) are higher among identical twins than fraternal ones. Suicide has been proven to be about 30-50% genetic. Additionally, the close family members of suicide victims are more likely to commit suicide. Parents, siblings, and children are at special risk. Some studies suggest the families of suicide victims are two times more likely to commit suicide than the rest of the population.

It's a sobering thought.

What causes suicide? Obviously, there are many factors. But studies suggest anywhere from 60 to 90% of those who commit suicide are affected by depression. In fact, depression is the most common factor to lead someone to kill themselves.

Studies have shown the brains of depressed suicide victims have fewer neurological receptors for the chemical GABA in their cerebral cortex. This affects decision making and thought processes.

The lack of GABA receptors in the brain is caused by the presence of methylation, a molecule that attaches to a gene and basically "hides" it from cells that would normally sense it and produce GABA receptors for it. The end result? The cells do not produce GABA receptors, and GABA cannot be filtered into the brain system as it should.

Even more striking is that this cause is not necessarily genetic. While the methylation does seem connected to depression and suicide, it is caused not be genetics but by environmental factors--factors such as childhood abuse, according to one study. Factors in childhood basically "program" the brain... and in this case, the lack of protein means the lack of synapses ("bridges" in the brain for neurons). When neurons cannot travel, gradually a person becomes starved of brain chemicals important for feeling happy and content, because these chemicals cannot travel as well with fewer bridges than in a healthy brain.

These environmental factors that basically seem to program the brain to be predisposed to depression and eventual suicide seem to happen prior to birth and in early childhood. Babies born with low birth weight and height were more likely to commit suicide as adults, as were children with abusive histories.

Of course, being at risk of suicide does not mean a family member will commit it. It simply means these people are in need of extra care and support. And, as always, if you feel like committing suicide, talk to a friend or call 1 800 SUICIDE.

http://www.sciam.com/podcast/episode.cfm?id=sylvia-plaths-son-and-suicide-in-fa-09-03-24
http://www.sciam.com/article.cfm?id=the-origins-of-suicidal-brains