Sci got an email from one of her lovely readers recently about an article that appeared in Scientific American. I usually have a lot of respect for Scientific American, but I have to say I feel they really dropped the ball on this one. So today, I present to you: what Sci Am said, the REAL story, and WTF is up with that.
Let's take it from the top.
Women's Brains on Steroids: Birth control pills appear to remodel brain structure
wooOOOooo. That poor attractive girl with a confused look. Those big PILLS. Science is HARD, you guys. Hard and SCARY.
Are you scared yet? You should be.
It seems that weekly we hear about some professional athlete who sullies himself and his sport through abuse of steroids. The melodrama unfolds, careers and statistics are brought low and asterisked, and everyone bemoans another fallen competitor. Yet there are millions of cases of steroid use that occur daily with barely a second thought: Millions of women take birth control pills, blithely unaware that their effects may be subtly seeping into and modulating brain structure and activity.
I think we can all spot the scare tactic "blithely unaware that their effects may be subtly seeping into and modulating brain structure". Oral contraceptives are COMING FOR YOU!!!! They will come in the night and CHANGE YOUR BRAIN STRUCTURE.
It gets better.
It found that birth control pills have structural effects on regions of the brain that govern higher-order cognitive activities, suggesting that a woman on birth control pills may literally not be herself -- or is herself, on steroids.
OH NOES! We are not OURSELVES! The same scare tactic employed by those against Prozac. WARNING: you may become "better than well". You may be "not yourself".
Ok. I'm done with the simple snark. This article really got Sci's goat. The basic idea behind the article is that a research study (they one they are referring to is this one), has found, using magnetic resonance imaging (MRI) for structural images of the brain, that there were differences in brain structure between men, normal cycling women, and women on oral contraceptives. The Scientific American article reported this as "a cause for concern", and spoke of the tendency of the brain to be "a veritable sponge for steroid hormones". These both may be true, but context is all, and I found the article to be needlessly scare-mongering, considering the paucity of the findings and the total lack of behavioral or cognitive aspects to the study. The writers of the Sci Am article did note this lack of findings, but this didn't seem to decrease their concern.
It's time to go to the article. What did they REALLY say, and what does it REALLY mean?
We have known for a while that men and women show differences in brain structure. The main differences we're concerned about with here are gray matter and white matter, which is really pretty basic in terms of brain structure. Gray matter is things like neuronal cell bodies and glia, while white matter is connective, containing the axons of neurons that are wrapped in myelin to make them conduct potential faster, giving the big connections a whitish appearance (Sci is really going to have to blog the basic anatomy of a neuron someday). Men and women have differences in the VOLUME of gray matter in various areas of the brain. Keep in mind that this has nothing to do with intelligence (just because you've got the volume doesn't necessarily mean you can make the best use of it), though it can impact specific kinds of reasoning skills. Women have more gray matter in areas like the cingulate gyrus and the parietal lobes (and it's more concentrated on the left side), while men have more gray matter in the parahippocampal gryus, the cerebellum, and the amygdala.
But gray matter volumes are not constant. I know that probably comes as a surprise, I mean, it's your BRAIN. It's an ORGAN, it shouldn't be all changing around. But it does. Your brain changes constantly in response to signals both from within and outside your body, and this means that new connections can be formed and new neurons be produced, depending on your circumstances.
And one of the circumstances that changes most often is HORMONES. Women have a monthly cycle of hormones, in fact, and this actually changes the gray matter levels in their brains on a monthly basis (your brain changes sometimes over days! Or hours! Or minutes! Doesn't that BLOW YOUR MIND?! It blows my mind). In particular, the big deal is between the follicular phase (where you ovulate), and the luteal phase (the maintenance phase which also includes menstruation). For a review of the cycle itself and the relevant hormones, see here.
Some studies have been done on the effects of the menstrual cycle of gray matter volume in women. During the follicular phase, there is increase gray matter in the hippocampus, but there is DECREASED gray matter in the parietal lobe, cingulate gyrus, and putamen. During the luteal phase, these volumes reverse, hippocampal gray matter goes down, and parietal, cingulate, and putamen gray matter goes up.
But that's when women are cycling normally. What about when they're NOT? What about when they are on the pill? So in this study, the scientists compared gray matter volumes in men, women without oral contraceptives, and women WITH oral contraceptives.
Above you can see the total gray matter volumes for men, women cycling normally in two phases, and women on the Pill. The total gray matter volume for men is higher, but don't let that mislead you, men are also BIGGER, and this graph did not control for body size, which I rather wish they had (men often have bigger brains than women because men themselves are bigger). The important comparison is that women on oral contraceptives have lower gray matter volumes overall than women NOT on oral contraceptives (if we go ahead and assume the women had approximately equal body sizes across treatment groups).
Now they get down to the nitty gritty and the brain areas.
What you can see here is all in comparison to MEN. The top group is women in the follicular phase, middle is women in the luteal phase, and bottom is women on contraceptives. When you see red, that's an INCREASE in gray matter compared to men, and when you see blue, that's a DECREASE in gray matter compared to men. What you can see is that women overall had more gray matter in the prefrontal cortex compared to men, and less in the parahippocampal gyrus compared to men. Women on oral contraceptives, however, had MORE gray matter than other women, and also had more gray matter in the cerebellum, even compared to men (usually men have more gray matter in the cerebellum).
There's a few more figures showing comparisons between just women on the pill and not, but the findings remain the same. Women who are NOT on oral contraceptives show changes in brain morphology in the two major phases of the menstrual cycle. Women who ARE on oral contraceptives do not show the cycle related changes, and show increased gray matter in some regions compared to women who are not on oral contraceptives.
Sci's got very few concerns about this study, actually. They looked for differences, they found them. Differences in brain structure and gray matter volume as related to oral contraceptive use. That's FINE. There's nothing particularly groundbreaking here (and it's in a pretty low impact journal, which could mean everything or nothing, but my guess is that it's because the study itself is so small and there are relatively few findings and experiments). But it's perfectly interesting. It's also important, it means that you may need to look at whether your female subjects are on oral contraceptives when you do certain kinds of brain imaging, or control for those potential effects. This is all well and good, they didn't claim anything but what they saw, and didn't speculate on anything they didn't study.
And that's where Sci Am took over. Oh NOES! We have differences in brain structure! That may mean there are differences in behavior and cognitive function!!! Did this study LOOK at behavior? No. Did it LOOK at cognitive function? No. Did it say ANYTHING AT ALL about whether or not these women were more or less "themselves" when on oral contraceptives. No. Of course it didn't. Because that concept is SILLY, and these scientists know better.
Unfortunately, just saying "Differences in gray matter volume in women on contraceptives" doesn't make for a very good story, does it. That sounds, you know, like normal science. Now...WOMEN ON STEROIDS! IT'S SEEPING IN AND CHANGING YOUR BRAIN!!! Now that's some exciting copy right there.
Look, we don't KNOW if these gray matter changes associated with oral contraceptives are changing behavior. Maybe they are (actually, probably they are in very subtle ways). But...what does it MATTER? This study didn't tell us that, and hinting at dark times ahead doesn't give us any answers either. Ok, a woman may not "be herself" while she's on oral contraceptives. What does that even MEAN?! What does it mean to be yourself? (Don't even get me started on "she may be herself, on steroids"). Are you saying that only normally cycling women are "themselves"? What happens when you, say, hit MENOPAUSE?! Are you no longer "yourself"?
Oh well, maybe that's different cause it's natural? NO. Changes in hormones are changes in hormones, regardless of where they are coming from.
Menopause is a difference in hormone levels, like normal cycling is a difference in hormone levels. Like oral contraceptives are a difference in hormone levels. Sci Am devolved this whole study into a scary story using that hot little buzzword "neuroplasticity". Neuroplasticity sounds good, and it IS. It's got lots of exciting brain findings associated with it. But neuroplasticity, changes in brain morphology, these mean NOTHING unless they are associated with, or even correlated with, changes in human behavior and physiology. Until you have an actual change in function resulting from these differences, it's just a different brain picture.
And the concept of "not being yourself". Well, when WERE you yourself exactly? When you're cycling normally? Your brain is changing then, too! In fact it's changing twice a month! Before puberty? Nope, not then, lots of new connections taking place and the brain isn't even fully built up yet. Definitely not during pregnancy, you're practically flooded with hormones then. And not at menopause either, lots of changes taking place there! To say that one condition or another makes you more or less "yourself" is a senseless comparison to make. EVERY drug will change your body. Are you "yourself" on Aspirin? Of course you are! You're "yourself" and you happen to have taken Aspirin. Just because it's over the counter does not make it less of a drug. Are you "yourself" on birth control?! Of course you are! Yes, there may be changes, and there may be changes that affect your behavior (see Prozac), but that does not make you less YOU, it merely makes you "you" AND on a specific drug.
So to conclude, don't let the rhetoric scare you. Until we have behavioral data on this, we cannot SAY whether there are scary effects. Maybe there are. Mostly likely the effects are not too scary, or we probably would have noticed. But we cannot say, and to imply scary effects when we do not know anything is to scare people to no purpose but to make people read.
Pletzer, B., Kronbichler, M., Aichhorn, M., Bergmann, J., Ladurner, G., & Kerschbaum, H. (2010). Menstrual cycle and hormonal contraceptive use modulate human brain structure Brain Research, 1348, 55-62 DOI: 10.1016/j.brainres.2010.06.019