Posted by Larry Hoover on January 19, 2009, at 8:03:27
In reply to Re: Epigenetics and mental illness, posted by SLS on January 17, 2009, at 20:58:53
> If you think about it, most cases of mental illness are epigenetic. The reason I say this is because there are always psychosocial environmental stressors and the resultant response in gene activity that creates changes in psychodynamics. Even the environment and events in the womb can be differential between identical twins. If the system is contemporaneously vulnerable to dysregulation with the exposure to these environmental stresses, gene activity - expression or non-expression - changes inappropriately. The native blueprints for checks and balances are disregarded.
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> - ScottI agree with you, Scott. I was trying to make a case for purely epigenetic phenomena associated with mental illness.
Up until now, vast effort and expense have been invested into finding genes associated with e.g. schizophrenia, or bipolar. There's a thread just up the page about this very subject. The problem I see is that these sorts of linkage analyses might help narrow down the biochemistry of etiology of the disorder, but the studies invariably turn up far more people with the unusual gene form who don't have overt symptoms than those who do. As well, frequently there's a majority who suffer from the disorder who don't have the gene, either. So, false positives and false negatives coming out the woohoo.
Getting back to your point, I would summarize to say that genes define the upper and lower bounds of physical expression of some trait, while environment determines where in that range the trait is expressed. And, the latter can change over time.
I'm beginning to suspect that these unusual genes that may confer additional risk of developing these mental conditions may actually, and coincidentally, happen to mimic the more common epigenetic changes that mediate the development of the disorder in the majority of cases. If this is the case, and we figure out how to re-regulate these genes, the idea of cure becomes at least a theoretical possibility.
Lar
poster:Larry Hoover
thread:874594
URL: http://www.dr-bob.org/babble/20090104/msgs/874904.html