Brain Scans Confirm: It's Hard to Be a Woman

(Aug. 11) -- New secrets of the female brain -- how it reacts to stress and monthly menstrual cramps -- have been revealed in two studies that harnessed brain scan science to better understand the distinct mechanisms by which hormones can affect a woman's mind.

1. Stress Differences Between the Sexes

First up is a study out of the National Institutes of Mental Health that sought to determine why women are twice as likely as men to suffer from mood and anxiety conditions like depression and post-traumatic stress disorder.

Brain scans on female and male rats revealed "striking gender differences" in susceptibility to stress hormones.

The key seems to be corticotrophin releasing factor (CRF), which is triggered during stress and attaches to receptors on cell membranes in the brain's "alarm center," leading to an aroused mental state.

Compared with females, male brains need more CRF to become agitated. And the receptors in male rats were also able to "retreat" inside cells, eluding CRF to minimize stress.

"When the going gets tough inside a locus ceruleus neuron, it's the female brain that acts 'macho,'" the study reads. "In response to a stressor, receptors for the stress hormone CRF remained exposed on the neuronal membrane in the female rat -- taking the full hit."

Word to that, ladies.

Except that if the findings hold among humans, they'd be a one-two hit of bad news about how women's brains react to unpleasant circumstances -- including one that's prevalent among more than half those of child-bearing age.

2. Menstruation's Pain on the Brain

Brain scans on 64 Taiwanese women revealed that participants who suffer cramps during menstruation, called dysmenorrhea, also experience remarkable brain changes in areas implicated in emotions and pain, according to a study published in September's issue of Pain.

The more intense the pain reported by participants, the more significant their structural brain changes, which persisted even when women weren't experiencing any discomfort.

"A long-term bombardment by peripheral pain can elicit plastic changes in the central brain as a reactive adaptation," Dr. Jen-Chuen Hsieh, the study's lead author, told Health Day. "It can also be a crucial mechanism that perpetuates the 'chronification' of pain" -- that is, a mechanism that can turn pain into a lingering affliction."

In other words, women who suffer menstrual cramps undergo brain adaptations that make them even more sensitive to the pain.

Sounds stressful. Which brings us full circle, back to that first study. It never ends!