The increase in certain hormone levels during the luteal phase causes women's mucous membranes, including those that line the nasal passages, to secrete more mucus. Dr. Lukas says that the increased mucus may act as a barrier to the absorption of cocaine when women snort the drug during the luteal phase of their menstrual cycle. He adds that other as yet unknown factors could also help produce cocaine's differing effects. Dr. Lukas says the findings, which he presented at the 1994 meeting of the College on Problems of Drug Dependence, might help explain, at least from a physiological perspective, why the prevalence of cocaine use among women has traditionally been much lower than it has been among men. According to the National Household Survey on Drug Abuse, approximately 3.1 million men and 1.4 million women used cocaine at least once during 1993.
Women also appear to take cocaine less frequently than men do.
The 1993 survey, which was conducted by the Substance Abuse and Mental Health Services Administration, estimates that about 365,000 men compared with 111,000 women used cocaine at least once a week. Many women have reported that they did not get high when they first tried cocaine, says Dr. Lukas, adding that women's low sensitivity to the drug combined with its high price create a strong disincentive to its continued use. On the other hand, he says, some women may become heavy users because they need to take more cocaine to get the same effect as men. If further studies substantiate Dr. Lukas' findings, they could have important implications for the treatment of cocaine abusers, says Dr. Elizabeth Rahdert, a research psychologist in NIDA's Division of Clinical and Services Research. Presumably, she adds, patterns of craving and response to withdrawal could also fluctuate with a woman's menstrual cycle, and treatment professionals would have to recognize that women could be more vulnerable to relapse at different points in their cycle.