Even when sober, some heavy marijuana users are dangerous drivers, a new study suggests.
The bad driving appears to be isolated to those who started using pot before age 16, researchers reported Tuesday in Drug and Alcohol Dependence. The theory is that early marijuana use changes the brain, leaving people more impulsive and more apt to make rash decisions.
In the new study, which tested participants in a driving simulator, researchers from McLean Hospital in Boston found that sober cannabis users who started using the drug in their teens had more accidents, drove at higher speeds and cruised through more red lights compared to people who had never used marijuana.
Marijuana is the most commonly used illicit drug in the United States, but there has been relatively little research on its health effects, particularly on teen brains.
“This research suggests that early exposure to cannabis may result in difficulties performing complex cognitive tasks,” said co-author Staci Gruber, an associate professor of psychiatry and director of Marijuana Investigations for Neuroscientific Discovery at Harvard Medical School and McLean Hospital.
Dec. 19, 201901:15
For the experiment, the researchers recruited 28 regular, heavy cannabis users (23 males and five females) and 17 non-users (six males and 10 females) whose driving abilities would be tested in a simulator. The participants’ average age was 23.
Those in the cannabis group reported having used the drug at least five out of the previous seven days and at least 1,500 times during their lifetime. They were told to abstain for at least 12 hours before their study visit to ensure that they weren’t high at the time of the test.
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