Simultaneous Use of Alcohol and Marijuana Places Teens at Increased Risk for Unsafe Driving

Teens that consume alcohol and smoke marijuana are at risk of indulging in unsafe driving, a new study reveals.

Researchers at the University of Michigan's Institute for Social Research in Ann Arbor say that teens who imbibe alcohol and marijuana together are more prone to indulge in risky behavior like driving .

A survey of 72,000 U.S. high school seniors conducted yearly from 1976-2011 under the Monitoring the Future Study was done. Researchers noticed that teens that used both alcohol and marijuana in the previous year had the most number of traffic tickets or warnings as well as highest rate of car accidents. Nearly 30 percent of these students were involved in road accidents. This risk was high among those who used alcohol and marijuana simultaneously. 

Over 50-90 percent of the teens reported indulging in unsafe and reckless driving.

"It's well known that both drinking and other drug use are linked to risky driving," said lead researcher Yvonne Terry-McElrath, of the University of Michigan's Institute for Social Research in Ann Arbor. "But this suggests that it's not only the frequency of substance use that's important. The patterns of drug use are also related to the risk of unsafe driving."

A decline in the use of drugs over time has been noticed. In 2011, a third of high school students said they had not touched either alcohol or drugs in the past one year compared to 12 percent  in 1979.

Yet there was a significant number of teen still using marijuana and alcohol in 2011.  21 percent  teens  were using both the drugs simultaneously, at least occasionally.  And it was these kids who suffered an elevated risk of unsafe driving when compared to the counterparts who just consumed alcohol or marijuana.

What remains a mystery is why this particular group of teens suffer an increased risk. But the researchers assume that intake of both the drugs simultaneously impairs their judgment to a great extent.

"Driver's education needs to talk more about the risks, in believable ways-not using inaccurate scare tactics," she said. "More broadly media messages about unsafe driving should go beyond alcohol. We often hear the message- Don't drink and drive. But we don't hear much about the risks of using additional substances, either alone or simultaneously with alcohol."

The finding was published in the Journal of Studies on Alcohol and Drugs.