Shepard Pratt's Derogatis agreed: "The most prevalent female sexual dysfunction is not arousal but desire. Viagra doesn't have a direct effect on that," he said.
Some women who have tried Viagra say their experience fits this view. "It doesn't work for desire," said Lillian Arleque, an executive coach and writer who lives in Andover, Mass. She began taking Viagra several years ago. "When you take Viagra it increases blood flow to your genitals. It increases sensation."
Arleque, 62, collaborated with Goldstein's wife, Sue, on When Sex Isn't Good, a book on female sexual dysfunction.
Hensley, the study investigator, said the key is targeting the right patients. "You need a woman who had good sexual function before taking antidepressants, and whose sexual problems were clearly a function of the [drugs]," she said.
For men, Viagra has been extremely successful. Since being introduced 10 years ago, it has been used by 35 million men around the world, according to Pfizer, which sold $1.76 billion worth of the drug last year.
"It's a drug that has changed society, and the world," said Goldstein.
After Viagra was introduced, Pfizer tested it extensively in women. Although it was safe, it wasn't particularly effective, and Pfizer stopped studying it in 2004.
A spokeswoman said the company is not currently pursuing FDA approval of Viagra for female sexual problems, a process that involves years of extremely expensive trials. "Pfizer currently has no plans to pursue an indication for Viagra as a treatment for female sexual dysfunction," said Sally Beatty, a Pfizer spokeswoman.
Although the company funded the research published today, it did not initiate the study, but instead awarded a grant to the researchers.
The study grew out of earlier work by the same researchers. A decade ago, New Mexico psychiatrist Dr. George Nurnberg and colleagues examined whether Viagra worked on men who were taking antidepressants. When the study found that Viagra helped, the researchers moved on to women who were taking the same antidepressants.
The drugs, known as selective serotonin reuptake inhibitors, or SSRIs, are consumed by millions of people with depression. Doctors write more than 160 million SSRI prescriptions a year, mostly for women, who suffer from depression twice as often as men.
SSRIs increase brain levels of a key neurotransmitter, serotonin. But increased serotonin often causes sexual problems in both sexes.
