It looks like some researchers have come close to nailing down one of the aspects of autism: A lack of regulation of some of the chemicals that transmit stimuli across nerve synapses.It's not the whole picture, but it is an important part of it.
Personally, I have always heard that some areas of the brains of autistics were shut down. Now I question that. How can individual areas be "shut down" if chemical processes are running rampant? How can it be that these rampant chemical processeses are confined to certain areas? Do certain areas of the brain hijack these processes and leave nothing for the rest of the brain? Is the rest of the brain starved of the chemicals necessary to pass along signals? Surely the brain has to have some spatial pattern to the signals it processes, but you would think that this kind of problem would screw things up so bad that there would be no hope whatsoever of anything recognizably rational. And then again, maybe this chemical imbalance somehow ends up being localized despite my intuition that this kind of problem should know no boundaries. Is this imbalance present even in the nerves in the rest of the body, leading to sound and touch sensitivities, etc.? Or are all those sensitivities related to problems in the brain? Could the high incidence of GI problems with autistics be related to nervous system problems?
It seems as though there are several drugs out there in Phase I or II clinical trials. This is one of them. It's called Arbaclofen, and it's related to a well-known drug called Baclofen.
Arbaclofen seems to be used for some GI problems, too.
Related NewScientist article.
INSAR article.
[ Note: This article suggests backing off the drug can aggravate behavior to some degree. I don't know if it ends up worse than when it started or not. ]
Another article pointing at genes related to synaptic function. I don't know what the source is! :-) Scroll down a bit and check out the "related articles" section for some interesting titles.
A rash of new drugs on the way from several manufacturers.