Your Child’s Brain on Your Drugs

We are a nation of drug users. Almost every single one of us has taken or will take some sort of drug. Whether it is illegal, coffee, Advil, anesthesia, or antidepressants, there is a drug to cure what ails us or at least improve our mood. Because of the inelegant way that current drugs are designed (this is changing, thankfully), often drugs bring side effects along with their curative, or at least stalling, powers. I’m sure we can all think of a prescription drug commercial where the happy woman with Herpes lists off the possible side effects of her wonder drug – one of them, inevitably, being death.

However, a new study points to a possible side effect of certain antidepressants that most mothers, or women who plan on becoming mothers, should know. Essentially, women who take antidepressants that are selective serotonin reuptake inhibitors, or SSRIs, up to a year before their child is conceived show a two-fold increase in autism in their children. The occurence  is most pronounced if the drug is taken during the first trimester – up to three times as much.

The  author says that the study, which included identical and fraternal twins, shows a greater environmental impact on children in the womb than genetic factors. But he stops short of saying that there is any conclusive evidence that any one chemical is the trigger. But let’s just call a spade a spade.

Most women are taught that alcohol consumption during the first trimester is a no-no, but both the third and first are critical times for brain development. And alcohol is a neurotoxin. It’s simply dangerous for a quickly growing brain. Which is why women are given a long list of nos: too many things can cause problems.

In the first trimester, the brain begins to form. So one might assume that if the mother is taking antidepressants, a brain-altering drug, that it could affect the brain development of that child much in the same way that alcohol can.

The human brain is programmed to develop in a very specific way. It is a bit of a rubix cube that neuroscientists are just starting to figure out, because for years they were stuck on neurons, not focusing on the really important brain players – the glial cells. Glial cells come in many forms, and make up the bulk of the brain. They are really responsible for most of our brain function, while neurons send the messages along. Not to say that neurons are not important, but they are only one part of a very complex system.

Anyway, one type of glial cell, the myelinating glia, is wrapped around every axon – the thin tendrils that extend from each neuron to deliver information across the brain. The myelinating glia serve as a type of insulation, so to speak. The more of it you have, the faster the electrical impulses can travel through your axons. So when you say that someone is “slow”, it could be that they just don’t have that much myelinating glia around their axons, and information does literally travel more slowly through their brain.

Basically, having more glia makes you smarter. In examining Einstein’s brain, a Berkeley neuroscientist found that although he had the same amount of neurons as regular men, he had much more glia. However, there is always too much of a good thing. Scientists (most of the info I am referring to is in The Other Brain, by R. Douglas Fields) have found that children with Autism often have a lot of myelinating glia.

I equate this to an over-insulation. Essentially, their axons are so well covered, that they process much more than other people, and get overwhelmed by the sheer amount of data they see. Someone with less myelinating glia can tune out this or that, mostly because their brain can’t process all of this information at once. For a person with Autism, they take it all in, and they can’t shut it out. It’s as if your car is set on driving 100 miles an hour, no matter what. It quickly becomes overwhelming to perform the simplest of tasks.

Now, I’m going to make a hypothesis, so bear with me while I speculate. If there is a genetic predisposition to Autism in a child, and that child’s mother takes antidepressants during the first trimester, perhaps something in those SSRIs triggers the developing brain to produce more myelinating glia. I say that a genetic predisposition has to exist, because the brain is a tightly controlled citadel. So there has to be a way in for things to go wrong. Just as alcohol can destroy neurons, perhaps taking away the ability to absorb serotonin into the fetal brain lets loose some other over-compensation.

serotonin is a neurotransmitter, meaning it is one of the chemicals in the brain used to send messages. If that serotonin isn’t sent, and myelinating glia have to work extra hard to glean what the neurons are sending (one function of myelinating glia is taking and storing information from neuronal transmissions and passing it on to the rest of the brain in a different fashion), then perhaps the brain to create more glia so that the brain functions properly in this serotonin-reduced environment. However, after the child is born, and they are no longer in a serotonin deprived environment, this extra glia is not needed, and in fact, can cause serious problems. This is of course, a very very amateur hypothesis. Either way, it makes sense that a drug targeted to the adult brain would also have an effect on the fetal brain.

Yet, in some women this will not have any impact. I would hope that scientists delve into the drugs we consume that affect the brain, because it is likely that there is more than one that can have a significant impact on fetal brain development. Like alcohol, which can be consumed in moderation with no ill effects, antidepressants are likely safe for most fetuses. But as our drug culture expands, and the incidence of Autism increases, its impossible not to wonder if in trying to cure one epidemic,  we are not simply creating another.


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