Many marijuana growers are trying to increase the content of the drug’s active ingredient, THC, as high as it will go, CNN reports. High-potency marijuana can lead to dangerous behavior, such as intoxicated driving, several experts say.

Generally, the most potent strains have a THC content of about 25 percent, the article notes. Dr. Mahmoud ElSohly, who directs the lab at the University of Mississippi that tracks the potency of marijuana seized by federal law enforcement officers, says they have found marijuana with a potency of 37 percent. In 1972, the average THC potency was less than 1 percent. That rose to 3 to 4 percent in the 1990s, and is almost 13 percent today.

“You really have to be careful,” he said. “The danger of this high-potency material is not with the experienced marijuana smokers, but young people who really don’t know what they’re smoking. They don’t know what to expect, and before they know it, they’ve inhaled too much.”

Dr. Julie Holland, a New York psychiatrist, says certain behaviors, such as driving, can be deadly for a person who is acutely intoxicated from THC. “The risk is not that you’ll stop breathing or that you’ll die,” she says. “The risk is that you’ll become very altered and disoriented, and you can get anxious and panicky in that situation.”

Dr. Stuart Gitlow, President of the American Society of Addiction Medicine, notes, “If you look at marijuana, the intensity has changed. So I would expect it to have a somewhat higher addictive potential.” He added, “ Most people are going to be fine, but there still will be that 10 percent of people who are going to get as high as they possibly can.”