CHICAGO - Viagra's effect in women has been disappointing, but a new small study finds those on antidepressants may benefit from taking the little blue pills.

The research involving 98 premenopausal women found Viagra helped with orgasm. But the benefits did not extend to other aspects of sex such as desire, researchers report in today's Journal of the American Medical Association.

"For women on antidepressants with orgasm problems, this may provide some wonderful relief," said psychologist Stanley Althof, director of the Center for Marital and Sexual Health of South Florida in West Palm Beach, who was not involved in the study. "But it will not improve their desire or arousal."

Antidepressants can interfere with sex drive and performance even as the drugs help lift crippling depression. Switching drugs or reducing the dose can help. But many people, men and women, stop taking them because of their sexual side effects.

Pfizer Inc. spokeswoman Sally Beatty said the company currently has no plans to pursue FDA approval for using its drug Viagra as a treatment for female sexual dysfunction. The company ended its internal research on Viagra for women in 2004. While Viagra was found to be safe, the results were inconclusive, Beatty said in an e-mail message.

The new study was funded by a Pfizer grant.

While 72 percent of the women taking Viagra reported improvement on an overall scale, only 27 percent of the women taking a placebo reported improvement.

Althof said it's "worrisome" that 43 percent of the women on Viagra experienced headaches, compared with 27 percent of the women on dummy pills.