What's Sex Got to Do with It?

By Jeffrey Kluger

If you have been moody and sad, unable to eat or sleep, chances are you suffer from clinical depression--unless, of course, it's just a bout of the blues. If you have a nasty habit of getting into brawls, chances are you are an antisocial personality--unless, of course, you are just a bit of a hothead. What determines whether you are sick or well? Often as not, it's whether you are male or female.

Diagnosing mental disorders has always been a tricky business, with doctors often relying on little more than observation, experience and the occasional hunch. Once the labels are applied, however, they stick, and medical texts tend to accept the results as truth--reporting, say, that two times as many women suffer from depression as men or that twice as many men suffer from alcoholism. Similarly, women are said to be more prone to anxiety disorders, while men may lean toward conditions stemming from impulsiveness and violence.

Is there something about our psychic makeup that makes one gender more vulnerable to some disorders than others? Or does it have more to do with societal roles? And if environment is the determining factor, will the illnesses that beset each sex change as society evolves?

Researchers seeking to answer those questions come up against a confounding mess of variables--everything from changing hormone levels to a patient's willingness to admit that a problem exists. But last summer a researcher at Stanford University tried to wave away some of the fog. Turhan Canli showed nearly 100 photographs--some of emotionally neutral objects like a fire hydrant, others of emotionally unsettling things like a severed hand--to 12 men and 12 women. Three weeks later he showed the subjects the same images and found that the women were 15% more likely to have accurately remembered the emotionally charged pictures than the men were. Brain scans produced by functional magnetic resonance imaging suggested why: the women stored both memory and the emotion linked with it in the same parts of the brain. The men used the identical brain regions but tucked away the emotion and the memory into different spots within them.

If women are better integrated emotional organisms, that difference may begin in the womb, when estrogen and progesterone help shape the function and structure of the brain. "The hormones are very physiologic," says Dr. Nada Stotland, professor of psychiatry at Rush Medical College in Chicago. "They have very measurable effects." Similar hormonal surges later in life may have an equally profound impact, triggering higher rates of depression among women between puberty (when estrogen starts to rise and fluctuate) and menopause (when the hormone is turned down low). Other--though less clear--physical differences may explain why boys are more likely than girls to develop such early-onset illnesses as autism.

But while biology is important, nobody discounts environment. Girls are taught early that the best way to manage feelings is to dredge them up and air them out. Boys are taught the value of suck-it-up silence. "Later in life," says psychologist Paula Caplan of Brown University, "women are thus more likely to come forward and ask for help."

Even the apparent connection between hormones and depression may be more environmentally linked than it appears. One study revealed that pubescent girls are more depressed in school systems in which seventh-graders attend the same school as ninth-graders, as opposed to K8 systems, in which students in Grade 7 remain near the top of the social ladder longer. "The problem may simply be that the girls become depressed when they encounter older boys at an earlier age," says Ron Kessler, professor of health-care policy at Harvard Medical School. In other cases, there is doubt whether a mental condition exists at all. Caplan believes that premenstrual dysphoric disorder--essentially high-octane PMS--doesn't belong in the medical literature. Eliminate the condition, and many women instantly get well.

None of these matters are close to being completely sorted out, but science is trying. Kessler is working with the World Health Organization to study 200,000 men and women in 28 countries, focusing particularly on the issue of gender and depression. Along with researchers from the National Institute of Mental Health, Kessler is taking surveys and saliva samples of 10,000 U.S. adolescents, hoping to correlate mental health and hormone levels. Will you find their results convincing? That also may depend on your gender. --With reporting by Sora Song/New York

With reporting by Sora Song/New York