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January 18, 2003

The causes of suicide

Scientific American has a little article on suicide. Some quotations: "I'm not saying that suicide is purely biological, but it starts with having an underlying biological risk." What's the biological risk? "At a conference of the American College of Neuropsychopharmacology in 2001, Arango reported that the brains of people who were depressed and died by suicide contained fewer neurons in the orbital prefrontal cortex, a patch of brain just above each eye. What is more, in suicide brains, that area had one third the number of presynaptic serotonin transporters that control brains had but roughly 30 percent more postsynaptic serotonin receptors."

As we discover more about brain architecture, we'll be seeing more discussions on the chemical basis for emotions and intelligence. Of course, the chemistry is controlled to a large degree by genetics...

Posted by david at 11:36 AM

so the question is-what is the average of suicide? if pre-modern humans in their wild state were dead by 30ish, and most suicides happen after 30, it would be less important. of course, the spread of the tendency for suicide might be a side-effect of traits that are selected for in agricultural and literate societies....

Posted by: razib at January 18, 2003 12:17 PM

I think suicide comes about from a combination of traits and personal experience. It's a unique blend of self-destructive impulses combined with personal history. Like schizophrenia, it might just be a by-product of some strange genetic combinations, where the genes themselves are helpful to most people, but in certain instances, detrimental.

Posted by: David at January 18, 2003 01:09 PM

interesting. Is there any evidence that environmental factors, e.g. alcohol or other neurtoxins, are causing the decrease in prefrontal cortex neurons? Yes, one could say in turn that alcoholism is in the genes, but unless one is born in an environment where alcohol is obtainable the point is moot. Anyway, David, in a nutshell if you will-what's the latest theory on neurochemical feedbacks, i.e. do you get depressed because of the genes or do you get depressed and cause the depressive genes to switch on?

Posted by: martin at January 18, 2003 03:38 PM

I think addictive behavior is general is partly genetic in origin. Some people go for booze, some for cocaine, some for heroin. But I think they all share similar neurochemistries predisposing them to addiction.

Same with depression--there's clearly a genetic component. Some people just have the brain chemistry that they're depressed at random times. Some people never get depressed,even after tragic events. Most people can get depressive (after prolonged difficulties in life) but don't stay that way. I think it's a gradient like most everything else. With suicide, your depressive tendencies are probably coupled with subtle differences in brain architecture.

As to the current theory, I'm not sure what's known about feedback in these systems. Neurobiology is a hobby, not my specialty, sorry.


Posted by: David at January 18, 2003 05:35 PM

I read this article, and was less than impressed. These are interesting correlations, but they don't seem to shed much more light on the problem of suicide than the medieval theory of the humors. I'm still unconvinced that any new lives will be saved by this sort of research.

Consider that the author herself was unsurprised to learn that her mom killed herself: her mom was erratic and depressed, and we already know, without knowing a thing about serotonin, that this is a behavior typical of suicides. Now let's imagine that we can screen people for this serotonin receptor hoo-ha. I'll bet we will end up identifying the same people who would already be considered suicide risks purely based on social-psychological criteria.

Posted by: Charlie Murtaugh at January 19, 2003 09:03 AM

I think people dont have jesus in their lives, without him, i myself would have no purpose

Posted by: MunkyGoo at April 24, 2003 08:35 AM

I have tried to commit suicide before, it obviously didn't work, I tried because my life sucked I had friends but no parents, had to work, go to school, so i resorted to drugs and achohol. My grades plummeted I couldn't pay the bills by myself. Besides, I was still depressed my mom had just ran out on me and my dad had left me 9 years earlier. And I didn't want to go to an orphanage. So, I tried to escape by killing myself. I was 12 years old and now I'm only 15. Sometimes, I still find myself wishing I were dead. And that pretty much describes how it goes for most children, overwhelming situations.....

Posted by: Heather at April 27, 2003 02:52 PM

Most people commit suicide or try to commit suicide because they don't know any other answer for their problems. Some people figure it would be better if they were just dead. A chemical imbalance doesn't necessarily mean a person will or won't try to commit suicide. When people aren't happy with themselves or with whom they have become is when depression comes in and feeling sorry for themselves, scared of their future, or the helpless feeling, is what may push a person to considering suicide. Then its still another fight on whether or not they have it in themselves to commit suicide for real. I really don't want to contradict myself but who are we to say he/she commited suicide or tried to because of this reason or that reason people just do it for their own reasons.

Posted by: Lakisha at September 24, 2003 08:22 PM