The biological impact of chronic stress
No one fully understands why women who have escaped from domestic violence get sick years later. But Bruce McEwen, a neuroscientist at Rockefeller University in New York City who is an expert on the biology of stress, says it makes complete sense that women who suffer domestic violence in their twenties are grappling, decades later, with diseases such as asthma, diabetes, hypertension and arthritis. Each of those conditions can be triggered by stress-related inflammation and a fight-or-flight response that’s in overdrive. “These women have been in a state of continual alert and vigilance, which is a very appropriate response if they’re living in danger,” McEwen says. “But if the woman’s situation becomes safer and she is still in a state of hyperarousal, as often happens, then you can have lasting problems. When the system that helps us survive is pushed to the limits and distorted, then it contributes to disease.”
McEwen calls that strain “allostatic load,” a runaway neurochemical and hormonal train that can be stoked for years—long after a woman makes her escape—by traumatic memories embedded in the brain. Such memories, stored in the amygdala, generate cytokines, chemical messengers that elevate inflammation in nearly every system in the body. In response, the body releases cortisol, the stress hormone. Normally the body’s system of checks and balances keeps that response under control. But if traumatic memories in the brain keep sounding the alarm for years afterward and generate too much inflammation for too long, the body can become desensitized to the regulating effects of cortisol, McEwen says.
The resulting inflammation can plug coronary arteries, jack up blood pressure, damage the body’s metabolic processes, inflame respiratory passageways and induce gastrointestinal distress. Meanwhile, in a one-two punch, cortisol floods the body, trying to stop the inflammation but instead disrupting sleep, promoting insulin resistance and accelerating atherosclerosis. Genetic predisposition may then determine why one woman becomes diabetic while another develops asthma or hypertension. “These women may have gotten hypertension anyway,” explains Jacquelyn Campbell of Johns Hopkins. “But instead of getting it at 60, they got it at 40, and it’s more difficult to control.” Just to make the situation more complex: “Women who are in abusive relationships often have also been the victims of child abuse, rape or dating violence,” she adds. “Many have seen their father hit their mother. They have these early pathways laid down, so when they’re beaten, it triggers all of that.” (See “How Domestic Violence Makes Children Ill.")
The abuse that leaves no marks
Psychological trauma does not have to be covered up with turtlenecks—and yet some studies show it is more likely than physical injury to generate chronic pain among women survivors. Marilyn Ford-Gilboe, the Canadian health researcher, has surveyed a group of 309 women who had left their abusers, interviewing them annually for five years. Broken bones, old concussions and sexually transmitted diseases are among their most common ailments. (Abused women have higher rates of STD transmission and cervical cancer, largely because they often lack preventive care and their abusers are frequently promiscuous.) But some of the women who suffer most from chronic pain, Ford-Gilboe says, experienced more psychological than physical abuse.