Science Fair: New Year, New Studies
An occasional column about science news pertaining to autism
Compiled by Robert B. Waltz
This study has been all over the news, perhaps because it's so dramatic and, for once, big enough to have statistical significance. A new, very large, study finds evidence that mothers who take antidepressants during the later stages of pregnancy are more likely to have children with autism.
A highly skeptical response (which uses some very sloppy language in describing the statistics) is at Forbes.com.
Commentary: As the stories themselves say, the results of this study are somewhat uncertain. There is plenty of data, but the meaning is hard to be sure about. Despite the third story, there does appear to be a correlation between antidepressant use and having children with autism. But, as statisticians love to say, correlation is not causation. There is also a correlation between antidepressant use and being depressed. So the results of this study would be the similar if women on antidepressants are more likely to have autistic children or if depressive mothers are more likely to have autistic children. There is another point that is now fairly firmly established; a wide variety of disorders -- autism, bipolar disorder, depression, schizophrenia, Tourette's -- are linked with a lot of the same genes. (That is, if you have genes X, Y, and Z in combination with some factor "A," you might get autism; if you have X, Y, and Z in combination with a different factor "D," you might get depression, where a "factor" can be genetic or environmental or a combination.) It is possible that antidepressants might be an autism factor, but we can't tell. Given the difficulty of separating depression from antidepressant use, it's likely to be a long time before we can be sure about this. Personally, I'd guess that this is case where both influences apply -- that both the depressive genes and the strange pseudo-hormonal effects of antidepressants can increase the odds of autism.
If you hear about neurotransmitters, it's usually dopamine or serotonin or norepinephrine, because those three are involved in rewards and in depression -- and, one suspects, because there are lots of drugs that fiddle with them. But they aren't the only chemicals which have active roles in brain chemistry. Another important one is Gamma-Aminobutyric Acid, or GABA. GABA has a role in calming down excess neuronal activity -- and, of course, one of the problems with autism is that people get too wound up. Now a study finds that providing more GABA may help with autism.
Commentary: Although certain writers are trumpeting this to the skies, caution here is absolutely required. This is very preliminary work -- the authors haven't tested effects of modifying the GABA pathway; they've merely found that people with autism seem to have a problem. So we'll have to wait to see if this leads to anything. The one minimally relevant result that I know about is personal: I was once placed on the drug gabapentin, which is supposed to do some of the same things GABA does -- and, in my case, it made things worse. On the other hand, I'm just one person, and my brain seems pretty strange even for a person with autism, and gabapentin isn't GABA anyway. My one real caution is that it should not be assumed, because this applies to some people with autism, that it applies to all.
A new study finds extraordinary risk of autism for babies born extremely prematurely (27 weeks or earlier). Among such infants, the rate of autism is on the order of 30%.
Commentary: Although the article expresses surprise at this result, I'm not really shocked. We know that extremely premature babies are at very high risk for just about everything, and few parts of the body are as vulnerable as the brain. My feeling is that this will eventually prove very useful as we try to understand the connection between genetics and environment in causing autism. Since being extremely premature is one of the most extreme environmental shocks possible, this may well give us a bound on just how much effect environment can have.
An examination of the brains of the deceased finds a difference between blood vessels in those with autism and those without -- in people with autism, the supply of blood to parts of the brain can vary, leading to less neurological function.
Commentary: This raises more questions than it answers, especially because so little real detail is supplied, e.g. about sample sizes and the nature and severity of both the vascular disorder and the autism. But even if I had that data, I'd be flummoxed. I can easily see how the condition described in the article would lead to mental retardation -- but autism is not mental retardation. It isn't even particularly linked to mental retardation -- most of the genes with an association to autism are linked to higher-than-normal intelligence. So I think there is something still to be discovered about this result. I won't speculate as to what.
A side comment: I find it interesting that, in the space of six days, I saw four reports of new autism causes. Of completely different sorts. It's not likely they're all right. So it seems as if we still have some looking to do.
Risperidone, one of only two drugs approved for autism (or, more specifically, for irritability associated with autism, which is not the same thing) has long been known to have not-so-nice side effects. Now you can add another one: It messes up your digestive microbiome, increasing the odds of obesity and all the other problems that come with a messed-up gut.
Commentary: I'd probably better put in a disclaimer here: I've never been on risperidone, but I did get forced (not by anyone at AuSM, I stress!) onto aripiprazole (Abilify), the other drug approved for autism -- and it was disastrous. It was helpful for irritability, all right: It irritated me no end. I personally find it hard to believe that these drugs (which are both anti-psychotics, which is another word for "really really nasty") are really suitable for use with autism. But I think I can safely say that it is now well-established that the state of the bacteria in your intestines has a lot to do with your health and well-being, so little wonder if these drugs cause obesity and other side effects.
Research from South Korea finds that compulsive video gamers have brains which are unlike non-gamers -- and that some of the changes are similar to the differences between neurotypicals and people with autism.
Commentary: Given how many people with autism are hooked on video games, I'm tempted to say, "Duh." The interesting question, to me, is whether these same differences are found in autistic people who don't play video games. (I ask because I don't play them; trying to play fast just gives me headaches.) Also, these changes sound very much like those found in people with Attention Deficit-Hyperactivity Disorder. So there is a lot still to investigate here.
Author bio: AuSM member Robert B. Waltz was diagnosed with autism in 2012. He earned his B.A. in physics and mathematics from Hamline University in 1985. He is the author of three books on folklore, the editor of the online folk music database The Traditional Ballad Index, and recently has been informally studying the biology of autism.