When it comes to risky behavior, drug and alcohol use and sex are strongly linked, according to a new study conducted at the Yale School of Medicine.

The analysis of this national study, conducted by School of Medicine assistant professor Jeanette Tetrault, found ties between alcohol abuse or dependence, marijuana consumption and the diagnosis of sexually transmitted infections in adolescents and young adults. The study analyzed data collected in the Substance Abuse and Mental Health Administration’s 2005 National Survey on Drug Use and Health, which investigated the substance use habits of over 50,000 Americans. Researchers and public health professionals said the results of this analysis, which was published in the November 2010 edition of the

American Journal on Addictions, could lead to more comprehensive questioning of STI patients that could prevent substance abuse in the future.

“The results of the study add to the growing movement to screen for substance use in primary care,” Tetrault said. “Often, we wait for substance use to become severe before intervening.”

The survey that provided the data for Tetrault’s study found that 2.5 percent of drinkers, 2.4 percent of binge drinkers and 3.2 percent of heavy alcohol users were diagnosed with a sexually transmitted disease in the past year, compared with only 1.4 percent for nondrinkers.

The results of the study did not find any STI association with the use of drugs other than marijuana, which Tetrault said may be attributed to inherent limitations of the survey because its responses were self-reported.

Doctors can draw from a number of screening indicators, such as mood changes or withdrawal from social activities, to determine whether a patient should be asked about substance use, Tetrault said. But at present, an STI diagnosis is not one of these indicators, she said.

School of Medicine assistant professor Dana Dunne, who studies STIs, said that regular primary care physicians might not think to ask a patient’s substance use history simply because the patient was diagnosed with an STI.

Jiang Yu, a research scientist at the New York State Office of Alcoholism and Substance Abuse Services, said in an e-mail that he hopes the results of the survey, which are consistent with his office’s data, will encourage doctors to provide early intervention for patients with substance abuse habits by referring them to further treatment if necessary.

But in more specialized clinics, patients are already screened, to some extent, for substance use.

Patients at Planned Parenthood are regularly asked about their substance use histories, said Jenny Carrillo GRD ’05, senior vice president of external affairs and organizational effectiveness at Planned Parenthood of Southern New England.

Connecticut’s public STI clinics also routinely inquire about their patients’ alcohol or drug consumption habits, Dunne said.

The most significant findings of the study were the strong correlations between drug use and STIs in adolescents and young adults.

Both substance abuse and STI patterns tend to cluster around the younger generation, Tetrault said.

“Adolescents come in with STIs, and we can diagnose and treat them, but we miss a key opportunity to ask them about their substance use problem,” Tetrault said. “I just hope people will feel comfortable and willing to talk to their doctors [about their substance use habits].”

Most adolescents and young adults only go to the doctor when they are sick, she said, adding she believes few would go if they felt they were developing a dependence on alcohol or some other drug.

Of four students interviewed, three said they would go to their doctors if they suspected that their drinking habits were becoming extreme, but expressed some reservations about the potential for “punishments” like counseling sessions and alcohol education workshops.

“Honestly, I would feel more comfortable talking to my dean than to a doctor,” said Emma McBurney ’12. “And I mean, everyone in college is an alcoholic.”

The National Survey on Drug Use and Health is conducted annually by the Research Triangle Institute, with funding from the Substance Abuse and Mental Health Administration.