Girls On The Brink

The Neurobiology of Belonging

Magazine Issue
July/August 2023

A good litmus test for the health of any society is how well it treats its girls and how well those girls are faring. By these measures, we’re failing pretty miserably. Most therapists are aware that depression is more prevalent in girls than in boys, but over the last several years rates among girls have soared to epidemic levels. One in four adolescent girls suffers symptoms of major depression, compared with fewer than one in 10 boys. Girls and young women are twice as likely as boys to struggle with anxiety. In 2021, the Centers for Disease Control and Prevention reported that suicide attempts had recently increased 51 percent among girls, compared with four percent among boys. And in February 2023, the agency reported that one in three teenage girls has seriously considered suicide, and 57 percent report feeling “persistently sad or hopeless.”

The question is, why? One explanation has been young people’s ever-growing immersion in the often judgmental and shaming world of social media. But while I believe this is a critical factor, it doesn’t fully explain the disparity between girls’ and boys’ mental health. As researchers seek to understand this phenomenon, they’re offering a new, neurobiological lens through which to view this growing gender gap in emotional distress.

The bottom line: at a body-brain level, girls and boys differ in how they process stress and trauma. (So far, we know less about those whose gender identity differs from the one assigned at birth.)

At puberty, girls’ brains become incredibly agile, taking in and processing information about the world, particularly social cues. Anyone who has raised an adolescent girl knows that her ability to rapidly “read the room” is unparalleled. When they grow up in healthy environments—where they feel they matter and belong, and that peers, parents, and other adults have their backs—these years are a time of incredible promise.

All too often, though, the coming-of-age landscape girls navigate is anything but healthy or safe. Add to this the influx of female hormones. Estrogen surges during puberty, just as young brains are being remodeled. On the plus side, the hormone is a superpower, boosting the immune system and stamina. It’s why females can do everything males can do during a typical day, yet do it in smaller bodies, with smaller organs, while still making room for a uterus that can carry another life.

Yet in the face of repeated threats—whether physical, social, or virtual—estrogen can also jack up the body and brain’s “stress machinery” in ways that testosterone does not. But let me be clear: this research in no way signals that female biology is somehow weak, or less-than, or that girls themselves are somehow to blame. Quite the opposite. The female body and brain are more susceptible to the adverse effects of stress only when that stress remains unaddressed and becomes chronic. In other words, when stress becomes toxic.

So let’s make sure it doesn’t. To thrive, girls need to feel safe, connected, and fully seen, and they can’t do that alone. The responsibility of adults—therapists, parents, teachers, mentors, and others who care about young people—is to help make girls’ precarious passage into adulthood smoother, easier, and therefore more joyful.

Safety First

To grasp the toll that feeling unsafe and excluded can exact on a girl’s body and brain, we have to step back in history to hunter-gatherer times, when humans faced the ever-present perils of predators and warring tribes. Unless you were constantly attuned to even minute signals of danger afoot, you died young. But beneath this basic survival instinct was a deeper biological imperative to survive through puberty in order to procreate and carry your genes forward. This was true for males and females, of course; but for females, the stakes were higher. Not only do females give birth, but mothers provide breast milk and maternal warmth—crucial resources for infants’ survival. Females had to stay alive long enough not just to safely reproduce and bear children but also to feed, nurture, and protect them throughout the perilous years of childhood. This required constant watchfulness and resourcefulness.

A female’s ability to pick up on even minute threats didn’t mean just being alert to immediate or obvious physical dangers. It also required staying highly attuned to social cues and emotional threats inside her tribe. For females in many human societies, being able to find enough food and shelter to support a young child depended on close cooperation and collaboration. If you were disliked, you and your children might be the last to get servings of meat when an animal was roasted on the communal fire. If a predator was nearby, you might not hear the call of alarm because you wouldn’t be near the heart of the tribe. In some instances, you might even be completely ostracized or abandoned without food, shelter, or protection.

Given the cascade of ill effects that could follow from even a small social slight, it made sense, anthropologically, that when one faced even moderate signs of rejection, one would begin to fear being excluded altogether. The resulting stress response would then rev up your immune system to get ready to do physical battle to help you survive.

For this reason, George Slavich, professor in the Department of Psychiatry and Biobehavioral Sciences at the University of California, Los Angeles, and other scientists believe that females evolved, generally speaking, to have a greater ability to perceive and detect threats. Slavich, who’s also the director of UCLA’s Laboratory for Stress Assessment and Research, refers to this link between experiencing a pervasive underlying sense of unsafety (which may be felt only at an unconscious level) and a prolonged physiological inflammatory stress response as the Social Safety Theory.

“Our perceptions of the events and conditions around us deeply influence our most basic internal biological processes, moment by moment,” Slavich explains. And “just as we know that developing and maintaining strong social-emotional bonds and feeling safe, seen, and known within relationships is a fundamental aspect of human happiness, experiencing emotional threats to our sense of social safety and to our connection with others raises our risk for both mental and physical health problems.”

Moreover, because feeling emotionally or socially unsafe may have predicted imminent harm, we’ve become highly adept at being able to imagine the mere possibility of being excluded in social situations. Among our ancestors, those who possessed the best “Spidey sense”—a finely-honed attunement to danger—and could pick up the possibility of being dissed before it even happened, would have been far more likely to survive.

And overall, females very likely had a better Spidey sense than males, because they had to live another day to have more babies and keep safe the ones they’d already brought into the world. Those females whose genetic makeup made them exquisitely attuned to potential threats, Slavich explains, “gained an enormous advantage: they survived, and so did their progeny.” But having this survival antennae came with a price tag: a greater propensity for one’s immune system to go into overdrive.

Slavich explains it this way. Abundant research has shown us that “just the hint of social threat or adversity, whether it’s feeling evaluated by peers, social conflicts, or feeling rejected, pricks up components of the immune system that ramp up inflammation.” Over time, this cascade of inflammatory stress chemicals and hormones can lead to changes in the architecture of brain, including how well the adolescent brain becomes wired and fired up for resiliency.

Now, this same response is also being activated by modern-day social threats. Being made fun of by the in clique? Imagining you might be excluded from an upcoming party that friends are posting about on Instagram? None of this is going to lead to your being physically wounded. And yet, to the human brain, it feels as if it could. “After all, the brain has been around for a lot longer than social media or even our current social structure,” Slavich explains.

And although nasty girls and frenemies have always been around, social media now amplifies those threats into everyday surround sound. This places girls on the dark hamster wheel of ruminating—often at night, alone in the dark, with no adult to turn to.

Meanwhile, puberty is starting a lot earlier for girls, before they have the time or experience to learn how to respond to those pressures in healthy and resilient ways. The parts of their brains that help discern how to put distress in context, or even how to ask adults for help, haven’t wired up yet, leaving them exposed to emotional slights before they have the experience to handle them.

For BIPOC girls, the effects of social stress often become even more magnified. They face the challenges of bullying and rejection against the backdrop of historical trauma, structural racism, poverty, and discrimination. Suicide is now the second leading cause of death in Black children ages 10 to 14 and the third leading cause of death among those ages 15 to 19. Black children are more likely to die by suicide than their white peers. During the past decade, the suicide rate among Black girls has increased at twice the rate as that among Black boys.

Racism—whether overt or structural—signals a threat to one’s survival, which can engender biophysical changes that profoundly affect well-being. As Wanjiku F. M. Njoroge, a child and adolescent psychiatrist at Children’s Hospital of Philadelphia, writes in a 2021 review in Current Psychiatry Reports, systemic, structural, and internalized racism “shape the health status of [BIPOC] youth.” Researchers at the Medical University of South Carolina recently concluded that current models of early childhood adversity have “largely neglected the multifaceted influence of racism on mental health outcomes.” This is something that needs to change.

Bouncing Back from Rumination

An activated stress-threat response in the face of social and systemic stressors is just one half of the story. Slavich observes that “it’s not just how strongly your brain and immune system respond when a social threat appears to be present. It also matters how quickly you are able to bounce back from worrying about potential social slights and move on, without ruminating about what might have happened.” For children, of course, this means it matters that they have a trusted adult to turn to, someone with whom they feel safe, seen, valued, and known, who can help regulate them, and help them bounce back. Being able to feel safe with and connected to caregivers and adults is the single most important ingredient in a child’s physical and mental health and in the health of the adult she or he will become.

“This social threat response is most beneficial when it turns on quickly to alert you to something bad and then turns back off again when the stressor has passed,” Slavich explains. The problem is that “the human brain is able to symbolically imagine threats happening in the past, present, and future, even when they are not actually happening in real time right in front of us. Just imagining that something bad is happening tells your brain that a hyperimmune response is necessary, which activates the stress response and your immune system.”

Ongoing rumination creates a potent inflammatory hit. Says Slavich: “The longer the period of time from [our] feeling under threat to getting to that recovery stage and feeling a sense of intrinsic safety and well-being again, the more the stress response shifts into a lingering state that can damage one’s health,” including one’s mental health.

Humans, as far as we know, are unique in their creative ability to symbolically imagine the motives and actions of others. And while it can help us be able to think through other people’s thoughts and intentions, it also means we tend to spend hours imagining the worst. We replay conversations or comments, ruminating about what we could or should have done differently, all the while trying to predict future events and preparing for how to handle them.

Even as you ruminate, says Slavich, “you can be experiencing the collateral damage of an elevated threat response even though there is nothing actually bad happening right in front of you.”

The Damage Cascade

It is this chronic vigilance in the face of potential threats that researchers believe plays a role in today’s mental health crisis among girls. Neuroscientists at Temple University have shown that, beginning in puberty, females are more likely than males to go into a state of high alert in the face of social stressors such as bullying or social-media shaming. Girls are also more likely to pump out increased production of stress-related inflammatory chemicals that are associated with depression and anxiety. Moreover, these elevated levels of inflammation often precede symptoms and diagnosis of depression and anxiety by years. Children who at age 10 show elevated levels of inflammatory factors have a significantly increased chance of developing depression by age 18. Furthermore, girls and women with higher inflammatory factors are three times more likely to develop depression within four years, relative to those with lower levels.

We also know that childhood adversity dramatically influences an individual’s vulnerability to developing depression, bipolar disorder, and suicidal ideation. In a 2020 meta-analysis of the literature, psychiatrists at Dell Medical School at the University of Texas, Austin, found that adverse childhood experiences (ACEs) were statistically “the single biggest contributor”—more than any single gene—to the risk of later developing a mental health disorder. The study authors write that the reason for this includes changes in levels of inflammatory factors that “contribute to disease vulnerability and a more pernicious disease course.”

While most therapists are well aware of the influence of ACEs on adult mental health, fewer may be aware of their dramatically differential impact on women and men. Ten percent of men who’ve faced two or more types of childhood adversity later develop major depression. But more than twice that number, 25 percent, of women who’ve experienced two or more categories of ACEs go on to develop major depression.

The fact that we respond to social threats like being left out or criticized on digital platforms as if we were being snubbed or injured by fellow members of our ancient tribe, is what evolutionary biologists call an “evolutionary mismatch.” The horror of feeling excluded triggers a harmful biophysical response, even though these feelings are unrealistic in response to, say, being made fun of on TikTok.

The Social Safety Theory tells us that our molecular makeup is extremely permeable to social–environmental influences, especially negative ones, and especially for girls. It helps us to understand why social media can be so damaging to the developing immune system and brain. It’s a question of safety. If you’re getting the constant message that, with one false step, you’ll be cast out of the social media pack, you learn that you’re not entirely safe among your peers. But social exclusion isn’t the only source of stress. If, at the same time, you’re getting the message that you’re not safe in a still-deeply sexist world—one rife with sexual harassment and abuse and a host of day-to-day assaults on girls’ self-worth and security—you learn that you’re not safe in the larger world. You’re not safe on any level. The stress-threat response never switches off.

Throughout human history, social–environmental threats were more likely to be life-threatening than they are now, but they were not a constant stressor. Now, in the digital age, the immune system is responding every minute to dozens or hundreds of likes, dislikes, and comments that signal acceptance or rejection.

Put all this science together, and it suggests that teenage girls’ immune systems respond more vehemently to negative stimuli in the world. And this happens during a critical timing window in neurodevelopment, during which the genes that will determine symptoms and disorders across the lifespan either turn off or on. The bottom line: today’s spike in chronic mental and physical health disorders among girls is both a biologically and a psychologically rooted phenomenon. We’ve created a social landscape that may be altering the female stress-immune response in ways that activate genes that derail thriving.

Experiencing a sense of safety is not binary, of course. One’s sense of safety exists on a continuum. Moreover, what might promote a feeling of inherent threat in one person might not do so in another, depending on the severity and quantity of adversities a child or teen has faced, their inherited resilience or genetic predisposition for disease, and, importantly, whether they have the support they need to help understand and process their stressors. Stress is made toxic when a child or teen experiences that stressor as harmful or threatening both when and after it occurs, without relief. The fact that girls today are suffering as they are tells us that on some deep and abiding level, girls feel unsafe in the world that we adults have created for them.

As therapists, parents, and others who deeply care for children, we must double down on teaching girls skills to help them feel safe and connected, and provide steadfast emotional support as they confront the demands of growing up female. But our job is bigger than that. We need to find enough social will to begin to change “the way things are for girls,” which means addressing the misogynistic machine that still sends girls the message—via social media and society at large—that if they want to fit in, they are what needs fixing, rather than the culture in which they’re coming of age.


Adapted from Girls on the Brink: Helping Our Daughters Thrive in an Era of Increased Anxiety, Depression, and Social Media, by Donna Jackson Nakazawa. Copyright © 2022 by Donna Jackson Nakazawa. Published by Harmony Books, an imprint of Random House, a division of Penguin Random House LLC. All rights reserved.


Read our book review of Girls on the Brink and watch our interview with the author.


Illustrations © ADOBESTOCK/JOEL

Donna Jackson Nakazawa

Donna Jackson Nakazawa is an award-winning science journalist, author of seven books, and an internationally recognized speaker, whose work explores the intersection of neurobiology and human emotion. Her writing has appeared in Wired, The Boston Globe, and The Washington Post. She’s the creator of the narrative writing-to-heal programs Breaking Free from Trauma and Your Healing Narrative, which help participants create a new, inner healing narrative that calms the body, brain, and nervous system. Learn more at