During the first half of their menstrual cycles, when their estrogen levels are high, women are protected from the brain-damaging effects of cocaine use, according to a research study conducted at McLean Hospital in Belmont, Mass., by a Harvard researcher and colleagues. Researcher Marc Kaufman believes that the finding could lead to a new drug to help in treating cocaine addiction. Cocaine harms the brain by constricting blood supply. In the study, estrogen counteracted the effect of cocaine administered to the test subjects. An estrogen-like drug, therefore, would minimize the damage that cocaine abuse causes. Kaufman believes that the results could apply to drugs other than cocaine. “There are other drugs that people are using like methamphetamines and other stimulants,” he said. “We don’t really know what those drugs do to the brain but some of them are vasoconstrictive like cocaine. Stimulants in general have the potential for altering blood flow in the brain.” The findings also could have much wider applications, such as reducing strokes.