But when they were asked about binge drinking, defined as five or more drinks once or twice a week, only 40 percent thought there was a major risk.
Only 32 percent of those asked believed smoking marijuana once a month posed a major risk.
The results are from the Substance Abuse and Mental Health Services Administration and are based on responses from nearly 50,000 individuals ranging from 12 to 17 years old.
The latest study comes on the heels of another earlier one this week that showed teen cigarette smoking is down to the lowest level since 1975, but that marijuana use is growing and prescription drug use remains high.
