Two new studies suggest that teens who binge drink or abuse prescription opioids may also be more likely to engage in other risky behaviours such as driving drunk or riding with drivers who are also under the influence.

They are also more apt to become extreme binge drinkers who experience blackouts, one of the studies suggests.

A second study suggests that teens who misuse opioids are also more likely to engage in risky driving behaviors. When teens abuse opioids, they’re more likely as well to misuse other drugs, engage in risky sexual behaviors, experience violence and attempt suicide.

“Substance use such as prescription opioid misuse may alter a misuser’s judgment and cognition, thus potentially increasing likelihood for engagement in other risky behaviors,”

Dr. Devika Bhatia, lead author of the opioid study

“Additionally, engaging in prescription opioid misuse may have an impact on peer groups that are more likely to engage in other risky behaviors,” Bhatia said by email.

For the opioid study, Bhatia and colleagues examined survey data collected from a nationally-representative sample of almost 15,000 U.S. high school students in 2017. Overall, 14% reported misusing prescription opioids at least once.

With any history of prescription opioid misuse, teens were 23 times more likely to have used heroin, almost 19 times more likely to have tried methamphetamines, over 16 times more likely to have tried cocaine, and more than 10 times as likely to have tried marijuana, researchers report in Pediatrics.

A history of prescription opioid misuse was also associated with five to six times greater odds that teens would try smoking or vaping, as well as a more than quadrupled chance they would have at least four previous sex partners and intercourse without condoms.

In addition, prescription opioid misuse was tied to more than six times the odds of drunk driving.

The second study looked in depth at driving outcomes associated with binge drinking. Researchers followed more than 2,000 teens for about four years starting in their senior year of high school, when 27% of participants reported binge drinking.

To assess binge drinking, researchers asked how many times teen girls had four or more drinks in a row within two hours, and how often teen boys had five or more drinks in two hours.

Compared to teens who didn’t binge drink during their senior year, those who did were more than five times as likely to drive while intoxicated during the next two years. Four years after high school, young adults who were teen binge drinkers were still more than twice as likely to drive drunk, researchers report in Pediatrics

Teen binge drinkers were also two to four times more likely to ride in cars with drunk drivers or experience blackouts in early adulthood. And young adults who were binge drinkers during adolescence were also twice as likely to become extreme binge drinkers.

Researchers also looked at whether parents’ awareness of teen drinking or parents’ efforts to discourage drinking might impact risky drinking and driving behaviors in early adulthood. Generally, young adults were less likely to engage in risky drinking or driving behaviors when they knew their parents were aware of any binge drinking during adolescence and when their parents discouraged drinking.

“Parental practices may have enduring effects protecting emerging adults against driving while intoxicated, riding while intoxicated, and blackouts several years after high school,” said lead study author Dr. Federico Vaca of Yale School of Medicine in New Haven, Connecticut.

When parents actively discourage risky behaviors, and pay attention when teens get into trouble, it may also impact the chances that young people will engage in other dangerous activities, Vaca said by email.

“Other negative consequences have a high likelihood of occurring with binge drinking, extreme binge drinking and/or blacking out including risky sexual behaviors, rape, and fights/physical assaults,” Vaca said.