The Female Brain (9 page)

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HY THE
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Think about it. Your brain has been pretty stable. You’ve had a steady flow—or lack—of hormones for your entire life. One day you’re having tea parties with Mommy, the next day you’re calling her an asshole. And, as a teen girl, the last thing you want to do is create conflict. You used to feel like a nice girl, and now, out of nowhere, it’s as though you can’t rely on that personality anymore. Everything you thought you knew about yourself has suddenly come undone. It’s a huge gash in a girl’s self-esteem, but it’s a pretty simple chemical reaction, even for an adult woman. It makes a difference if you know what’s going on.

The trouble for some women is caused by estrogen and progesterone withdrawal in the brain, which happens in the fourth week of the cycle. The hormones bottom out precipitously, and the brain begins yearning for their calming effects. When it doesn’t get them, the brain becomes irritated, so irritated that it’s on the same spectrum of discomfort as a seizure. This is true in a small percentage of women, to be sure, but it’s not fun. So stress and emotional reactivity can increase dramatically the few days before the onset of bleeding. At the National Institute of Mental Health in Bethesda, Maryland, David Rubinow and colleagues have been studying menstrual mood changes. They’ve now found direct evidence that the hormone fluctuations during the menstrual cycle increase brain circuit excitability, as measured by the startle reflex, which most of us think of as being jumpy. It is also related to the stress response. This helps explain why women often feel more irritable during maximal hormone withdrawal.

Although 80 percent of women are only mildly affected by these monthly hormone changes, about 10 percent say they get extremely edgy and easily upset. Females whose ovaries make the most estrogen and progesterone are more resistant to stress because they have more serotonin (a chemical that makes you feel at ease) cells in their brains. Those women with the least estrogen and progesterone are more sensitive to stress and have fewer serotonin brain cells. For these most stress-sensitive individuals, the final days before their periods start can be hell on earth. Hostility, hopeless feelings of depression, plans for suicide, panic attacks, fear, and uncontrollable bouts of crying and rage can plague them. Hormone and serotonin changes can result in a malfunction in the brain’s seat of judgment (the prefrontal cortex), and dramatic, uncontrolled emotions can push through more easily from the primitive parts of the brain.

Shana was in this category. During the week or two before her period, she was constantly in trouble for talking out of turn and being disruptive in class. She was obnoxious and aggressive one minute, bursting into tears the next. Pretty soon, her moods turned wild, and she began to intimidate her parents, peers, and teachers. Repeated meetings with the principal and school counselor did nothing to curb her outbursts, and when her parents finally sent her to a pediatrician, he too was baffled by her extreme behavior. It was a female teacher who noticed that Shana’s behavior was at its worst during two weeks of each month. The rest of the time she was like her old self—or more like a typical teen—sometimes moody and oversensitive but mostly cooperative. On a hunch, the teacher called me at the clinic to suggest that Shana had bad PMS.

Shana’s mood and personality swings, while extreme, were no surprise. In twenty years of practice in psychiatry and women’s health, I’ve seen hundreds of girls and women with similar problems. Most blame themselves for their flare-ups of bad behavior. Some have been in psychotherapy for years trying to get to the bottom of their recurring sadness or anger. Many have been regularly accused of substance abuse, bad attitudes, and bad intentions. Most of these assumptions are unjust, and all of them completely miss the point.

These adolescent girls and adult women have regular, dramatic shifts in their moods and behavior because, in fact, the very structure of their brains is changing, from day to day and from week to week. The medical name for an extreme emotional reaction during the weeks before the period, triggered by ovarian estrogen and progesterone hormones, is premenstrual dysphoric disorder (PMDD). Women who have committed crimes while suffering from PMDD have successfully used it as a defense in France and England by establishing temporary insanity. Other common conditions—such as menstrual migraine—are also caused by increased brain circuit excitability and decreased calming right before the period starts. Researchers at the National Institute of Mental Health found that the emotion and mood changes these women experience during the menstrual cycle disappear when the ovaries are blocked from producing fluctuating hormones. It may be, they conclude, that women with PMDD are in some sense “allergic” or hypersensitive to fluctuations in estrogen and progesterone during the cycle. Fifty years ago, one successful treatment for PMDD was removing the ovaries surgically. At the time, this was the only way to remove the hormone fluctuation.

Instead of removing Shana’s ovaries, I gave her a hormone to take every day—the continuous birth control pill—to keep her estrogen and progesterone at moderately high but constant levels and prevent her ovaries from sending out the big fluctuations of hormones that were upsetting her brain. With her estrogen and progesterone at constant levels, her brain was kept calmer and her serotonin levels stabilized. For some girls I add an antidepressant—a so-called SSRI (selective serotonin reuptake inhibitor)—which can further stabilize and improve the brain’s serotonin level, in other words, improve one’s mood and sense of well-being. The following month her teacher called me to report that Shana was back to her good old self again—cheerful and getting good grades.

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The day Shana screamed that she wanted to go to the beach, Lauren had been concerned about her daughter’s boyfriend, Jeff. Jeff was from a very wealthy and permissive family, and at fifteen, Shana had already had sex with him. Jeff ’s parents allowed them to do it in their house, a fact Shana had kept hidden from her parents until she had a pregnancy scare. Since Jeff wasn’t going away, Lauren decided it was best to get to know him. And the more she did, the more she liked him. Jeff was lavishing Shana with gifts (something Lauren wasn’t thrilled about, but she didn’t want to hurt his feelings), and Shana was happy when he was around. She made deals with her parents: “Come on, Mom, I’m really stressed out, and if he comes over for an hour I’ll feel better. I promise to finish my work after he leaves.” She often snuck him back in, and the two were thick as thieves.

Shana had been seeing Jeff for eight months. The day after she told her mom how much she loved him, Shana showed up at home after school with Mike, a boy she had sworn was just a friend. When Lauren went up to check on them, the door was closed. When she opened it, they were, as she put it, “sucking face.” Since she had allowed Shana to be sexually involved with Jeff, Lauren didn’t know what to do. It was clear that Shana’s impulses were getting out of control.

A girl’s emotional centers become highly responsive at puberty. Her brain’s emotion-and impulse-control system—the prefrontal cortex—has sprouted many more cells by the age of twelve but the connections are still thin and immature. As a result, a teenage girl’s mood changes, resulting in part from the increased emotional impulses blasting in from the amygdala, are more rapid and dramatic. Her prefrontal cortex is like an old dial-up modem receiving signals from broadband. It can’t handle the increased traffic from the amygdala, and it often becomes overwhelmed. Teenagers, therefore, often cling to an idea and run with it, not stopping to consider the consequences. They become resentful of any authority that wants to head off their impulses.

My patient Joan, for example, remained in upstate New York the summer after she graduated from boarding school there. An honors student, she had been involved with a local guy who didn’t graduate high school, had been in juvenile detention, and at age sixteen had fathered a child. She ran around with him all summer, and when it came time to leave for college, she thought twice about it. She wanted to stay with him. When her parents threatened to come up, take the car, and drag her off to college, she ran away with her boyfriend. She did come to her senses and go to college, but it was a long time before she spoke civilly to her parents again. It’s tough for the teen brain to come up with good judgment in these situations.

Remember Romeo and Juliet? If only the two lovers had known that their brain circuits were under major reconstruction. If only they’d known that their sex hormones were causing brain cells to grow and sprout extensions, and that it would take several years to form structurally sound connections once those extensions were plugged into the correct outlets in mature prefrontal cortexes. Juliet’s brain would have matured two to three years earlier than Romeo’s, though—so she may have come to her senses sooner than he. These unfinished—unmyelinated—extension cords, most prominent in the connections from the emotion center of the amygdala to the emotional control center of the prefrontal cortex, need to be coated with a substance called myelin that allows for fast conduction before they can function reliably under stress. This may not happen until the late teens or early adult years. Without the fast connection to the prefrontal cortex, big downloads of emotional impulses often result in immediate, raw behaviors and circuit overload.

When it is upset by an unwanted parental restriction such as, “We know you were drinking at the party, and you’re too involved with boys, and your grades are going down, so you are grounded,” the teen girl amygdala may not respond with much more than “I hate you.” But watch out for the subtle signs of rebellion that can ensue. She’ll find another way to undermine you.

Karen, a former patient of mine who is now a tenured professor of biochemistry, told me a story that illustrates this teen reality. She grew up in a small town in Washington State, where many students dropped out of high school to work for the lumber companies in the area. Her girlfriends got jobs as cooks or secretaries in the lumber camps, or got married and almost immediately became pregnant. By the time she was a sophomore in high school, Karen was desperate to get away from home. She was determined to go to college, a radical idea in a town where only the teachers, the doctor, and the librarian were college graduates. Her parents accused her of living in a fantasy world. They didn’t have the money to send her, and what did she think she could do with a college degree when she would likely get “knocked up” by the time she was twenty?

Their scorn made Karen even more determined to find a way out. At eighteen, she wanted to stay in school and graduate. But she was old enough to get a job as a go-go dancer in one of the local bars that serviced the lumberjacks who came into town to spend their paychecks. She moved in with her boyfriend and worked nights at the bar. Too young to go topless, she still managed to earn twenty-dollar tips, which the customers would stick in her G-string.

Not exactly the typical line of work for a future biochemistry professor. But Karen earned enough money to pay for her first semester at college, and after that, her grades were rewarded with a full scholarship. Now that Karen is herself the mother of three teenagers, two girls and a boy, she tries to imagine how she would react if her eighteen-year-old daughter announced that she had just gotten herself a job as a pole dancer in a bar. She herself had avoided any dangerous incidents, but her go-go gig could have turned out otherwise.

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HANGING HORMONAL CONDITIONS
in girls’ brains through the menstrual cycle add even more volatility to the mix. If estrogen and progesterone simply increased during the teen years and remained at that new, higher level, the female brain would permanently readjust. But, as we have seen, these hormones come in waves. Given the fact that the teen brain is undergoing major changes, especially in areas that are particularly sensitive to shifts in hormones, puberty can be an outrageously impulsive time for many girls. Under no stress on a good week of the menstrual cycle, the teen girl’s prefrontal cortex may function normally. At those times she may have good judgment and appropriate behavior. But some stress—like a disappointment or a bad grade—on a PMS day may derail the prefrontal cortex, causing an exaggerated emotional response and out-of-control behavior, such as yelling and slamming doors, what at my house we call a meltdown. Testosterone surges in teen boys may have similar brain effects, but these have not been studied yet. Hormone surges at this age can make a mild stress or a seemingly small event feel like a catastrophe.

Calming down the fired up teen girl amygdala can prove difficult. Many girls turn to drugs, alcohol, and food (either they’ll stop eating or they’ll binge) when they’re under stress. As a parent of teens, you have the job of ignoring much of what they say. Don’t take any impulsive or emotional tirades seriously. Stay calm. Teens state their intentions—and feel them—with such passion—that you can be persuaded in spite of yourself. Just remember, your teen daughter’s impulse-control circuits can’t handle the input. Like it or not, you must provide the control while her brain cannot. Even though Joan hated her parents for threatening to come and take her car away, “they did the right thing,” she told me years later. It was their job to exercise the good judgment that she lacked at that time.

D
EPRESSION

It wasn’t long before even Mike began to realize Shana’s impulses were out of control. If she could turn on a dime about Jeff, she could change her mind about him, too, and he decided to break it off. A few of Shana’s friends were also mad at her over how she’d treated Jeff, and she was becoming isolated. Up until then, Shana had been doing well. She was writing for the school newspaper, was becoming serious about sculpting, and was going to have a good pick of colleges. Her teachers loved her creativity and spark. But when Mike broke it off, everything changed. Shana lost a ton of weight. She stopped doing well in school. She let the school paper down by not writing stories that were assigned. She couldn’t concentrate or do her homework, couldn’t sleep, was obsessed with her weight and appearance, and couldn’t get her brain to stop thinking about
him
. I could see a few scratches on her arm and realized she was cutting. I was quite alarmed, since this is the period when the female-to-male ratio for depression doubles.