On June 18, an advisory panel for the Food and Drug Administration recommended against the approval of flibanserin, which had been touted as a female Viagra. The FDA can accept or reject the panel's advice but usually chooses to follow it. In many drug approval proceedings, that would be the end of the matter.
Together, the hearing and campaign fueled a long-standing debate over how to define, diagnose and treat low sexual desire in women.
Some medical experts say that low libido, or female sexual dysfunction, is a condition that can and should be treated with medication. Others say that a woman's sexuality is far too complex and is affected by too many other aspects of her life to be reduced to treatment with a pill.
This disagreement has been ongoing despite — or, perhaps, because of — the fact that sexual dysfunction disorders were introduced in 1980 to the Diagnostic and Statistical Manual of Mental Disorders, which is used for diagnostic purposes by medical professionals.
Some people are trying to propose that no medication for female sexual dysfunction should be approved because it's a fabricated condition, said Laura Berman, a sex therapist and author of "The Book of Love."
Berman herself disagrees. "There are real medical factors. Sexual response and sexual factors are in part physiological; you can't ignore that."
Hypoactive sexual desire disorder, which flibanserin was proposed to treat, is one of seven sexual dysfunction disorders currently listed in the DSM that can affect women. It's defined by a near, or complete, lack of sexual fantasies and little to no desire for sex, and it requires that a woman experience distress over her sexual functioning. Among the other disorders are female sexual arousal disorder, defined by the inability to become and stay sufficiently vaginally lubricated; female orgasmic disorder; and pain during intercourse.
Researchers have attempted for years to find solid numbers reflecting how many women suffer from female sexual dysfunction disorders.
One of the most frequently cited studies analyzed data from a 1992 National Health and Social Life Survey. Published in the Journal of the American Medical Assn. in 1999, the study found that 43% of women surveyed, ages 18 to 59, experienced sexual dysfunction. Of that 43%, 22% cited low desire, 14% had problems with arousal and 7% experienced sexual pain. In this and other studies, women younger than 35 were found to experience more distress over their sexual functioning than their older counterparts.
The findings, while still used by experts, came under some scrutiny when the lead researcher later revealed ties to pharmaceutical company Pfizer.
In other studies looking at the prevalence of female sexual dysfunction, results have been notoriously divergent. Over the years, researchers have estimated that from less than 10% to more than 50% of women ages 20 to 65 and 18 to 49, respectively, have experienced notably or long-lasting low sexual desire, according to a paper published in the Archives of Sexual Behavior in 2009.
The inability to establish a more precise number of women affected comes as little surprise to some medical experts. They say there are inherent difficulties in diagnosing female sexual dysfunction.
To begin with, known causes of low sexual desire in women are nearly innumerable.
In older women, hormonal change from menopause may be the culprit. But in younger women there's rarely an underlying physiological factor at play, says Dr. Bernadith Russell, a fellow at the American Congress of Obstetrics and Gynecologistswww.acog.org/ and the chairman of that group's task force on female sexual dysfunction.
"There are some tests that I would do in premenopausal women," she said, including assessments of thyroid function and screening for diabetes or endocrine disorders, "but that's unlikely to be the cause."