Researchers analysed 2007 to 2011 data gathered from more than 7,400 U.S. high school seniors who said they had used alcohol or marijuana at least once.
The investigators found that drinking alcohol was associated with more unsafe driving, damage to relationships with friends and romantic partners, and regret about actions while under the influence of alcohol, especially among females.
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On the other hand, marijuana use was more often tied to worsening relationships with teachers or supervisors, less energy or interest, and poorer school or job performance, according to the New York University (NYU) researchers.
Nearly half of high school seniors have used marijuana
"Nearly half of high school seniors have used marijuana in their lifetime and over two-thirds have used alcohol, but few studies have compared adverse psychosocial outcomes of alcohol and marijuana directly resulting from use," study author Joseph Palamar, a researcher affiliated with the NYU Centre for Drug Use and HIV Research, said in a news release.
The most "alarming finding" was the degree to which drinking was tied to reckless, unsafe driving among youth, Palamar said.
"Compared to non-drinkers, frequent drinkers were over 13 times more likely to report that their alcohol use has led to unsafe driving. Marijuana users, compared to non-users, were three times more likely to report unsafe driving as a direct result of use," he noted.
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"Not unexpectedly, we found that the higher the frequency of use [of alcohol or pot], the higher the risk of reporting an adverse outcome," Palamar added.
Drinkers more likely to regret it
Among people who said they regretted past actions, the likelihood of regret was higher among frequent drinkers than among those who used marijuana, he said.
The study could only point to associations between drinking or pot use and various outcomes; it could not prove cause and effect. The research was published in the American Journal of Drug and Alcohol Abuse.
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The researchers noted that growing support for marijuana legalisation in the U.S. has led to debate about whether marijuana is safer than alcohol and other substances.
"We hope that the findings of this study will contribute to the ongoing debate on marijuana policy and its perceived harm when compared to alcohol," Palamar said.
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Image: Teen smoking and drinking from Shutterstock
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