A woman's risk of being raped during college is highest during her freshman year, studies have shown. Now, researchers who want to understand which women may be at greatest risk of experiencing sexual assault while they are incapacitated due to drugs or alcohol during their first year say they have uncovered two factors linked with women’s risk of sexual assault.

"The strongest predictor of sexual assault during first year of college is a history of assault prior to college," the findings of a new survey show, said Kate Carey, the author of the new study and a professor of behavioral and social sciences at Brown University School of Public Health, in Providence, Rhode Island.

The second factor that the survey found to be linked with women's risk of sexual assault while they were incapacitated during their freshman year was the students' views of the relationship between alcohol and sex. Women who said at the beginning of their freshman year that they believed that drinking alcohol could enhance a person's sexual experience were more likely to be raped during their first year of college than those who did not hold this belief.

The researchers are certainly not suggesting that rape victims who drink or use drugs are to blame for experiencing rape, Carey said.

"We wanted to try to understand, in this case, was there anything that characterized the women before they got to college that would help us understand who was at greatest risk of experiencing sexual assault in that first year," Carey said. "If we knew that, we may be able to to tailor early prevention programs on campus a little bit better."

The new results suggest that interventions, such as educational programs, aimed at changing the way students think about alcohol and sex could potentially be useful in reducing sexual assaults, she said.

In the study, researchers surveyed 483 incoming first-year female undergraduate students at a private university in New York state, and followed up with them three more times during their freshman year. The students were asked about whether they had been raped, and about the use of several perpetrator tactics, including raping a woman while she was incapacitated by drugs or alcohol, and unable to object or consent.

About 15 percent of the students said they were raped that year while they were incapacitated from drinking alcohol or using drugs, the survey found. [9 Ways Going to College Affects Your Health]

But 18 percent of the students in the study had experienced rape while they were incapacitated from alcohol or drug use before they entered college, and among those women, 41 percent were raped again while they were incapacitated during their first year of college.

"The pre-college assessment went back to as early as age 14," Carey said in a statement. "That suggests that sexual assault education needs to begin earlier."

Moreover, the study showed that how people think about alcohol and sex is also predictive of who is going to experience assault in that first year, she said. "These are thoughts and attitudes that people have about how alcohol affects them and how they feel when they are drinking — and those can be changed," Carey told Live Science.

Because the survey was done at only one school, further research should look at the results at other schools, Carey said.

Drinking alcohol and using drugs are common on college campuses, with four of five college students drinking alcohol, and half of these saying they sometimes binge, according to the U.S. National Institute on Alcohol Abuse and Alcoholism.

"Rape is a complicated outcome and incapacitated rape involves drinking, but it also involves a perpetrator," Carey stressed.

"Even though we are focusing in this one particular study on the potential victims' risk factors, that is just one piece of the puzzle that doesn't take into account the risky environments and also the characteristics of the perpetrators," she said.

Researchers are starting to understand the prevalence of sexual assault on campuses, and some of the risk factors that it may involve, Carey said.

It is important to make sure that these interventions aimed at preventing rape "should not just focus on women; they should focus on the whole campus community," she said.

The new study was published in the November issue of the Journal of Studies on Alcohol and Drugs. Some of the findings from the survey were previously published.

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