A woman’s perception of other kinds of rewards—such as money, food and sex—may also vary during her menstrual cycle. In a 2007 study researchers at the NIH scanned women’s brains using functional MRI as the women played slot-machine games. They found that women’s reward circuitry was more active when they won jackpots during the estrogen-governed phase of their cycles than during the progesterone-infused phase that follows. The ebb and flow of female hormones could thus have broad effects on the perception of pleasures and incentives, influencing women’s motivation to engage in a wide variety of behaviors.
A Smarter Way to Stop
Artificially boosting progesterone levels in women tempers the “high” they get from drugs. In a 2006 study Evans’s team gave 11 female cocaine users progesterone when their bodies’ natural levels of the hormone were low. The treated women reported feeling a reduced high as compared with the one they got at the same point in their cycles in the absence of additional progesterone. (In contrast, progesterone did not influence the subjective experience of cocaine smoking in the 10 male addicts they tested, although the researchers are not sure why.) If progesterone dampens the pleasure of drugs, it might help treat addiction in women—something Evans is currently testing in female cocaine addicts.
Short of a chemical fix, paying attention to the calendar could help women succeed at quitting smoking, drinking or using drugs. In a study published in 2008 Sharon S. Allen, a family medicine doctor at the University of Minnesota Medical School, and her colleagues asked half of 202 female smokers to try to quit during the second part of their cycles—when progesterone levels are high—and the others to make the attempt earlier in their cycles. The results were stunning: 34 percent of the women in the first group had not smoked 30 days later as compared with only 14 percent of those who tried to stop smoking when progesterone levels were low. “When women are smoking early in their cycle, they’re getting more of a kick from their nicotine, more pleasure maybe, so it might be harder to quit,” Allen explains. In this mix of hormones, brain chemicals and desire—as in many other parts of life—timing may be everything.
This article was originally published with the title She's Hooked.