The percentage of U.S. college students who say they smoke marijuana daily or nearly every day is at its highest in more than three decades, according to a new survey.
In 2014, 5.9 percent of college students said they smoked marijuana 20 or more times in the prior month. That's up from 3.5 percent in 2007, and is the highest rate of near-daily use reported since the survey began, in 1980, the researchers said.
In fact, in 2014, near-daily use of marijuana was more common than daily cigarette use for the first time, the researchers found. Just 5.2 percent of college students said they smoked cigarettes every day, down from about 19 percent in 1999.
In addition, the percentage of college students who said they used marijuana at least once a month increased from 17 percent in 2006 to 21 percent in 2014. In addition, the percentage of college students who said they used the drug at least once a year rose from 30 percent in 2006 to 34 percent in 2014.
The increase in marijuana use may be tied to a change in how young people view the drug. In 2006, 55 percent of 19- to 22-year-olds said they viewed regular marijuana use as dangerous, but in 2014, just 35 percent said the same, the survey found. Also in recent years, an increasing number of states have legalized the drug, for medical or recreational purposes. [The Drug Talk: 7 New Tips for Today's Parents]
A similar rise in marijuana use has also been seen among high school students, said Lloyd Johnston, a research scientist at the University of Michigan's Institute for Social Research, who led the study.
The survey also found that use of amphetamines— such as Adderall— for nonmedical reasons is also on the rise in college students. In 2012, 11.1 percent of college students said they had used amphetamines for nonmedical reasons in the past year, up from 5.7 percent in 2008.
"It seems likely that this increase in amphetamine use on the college campus resulted from more students using these drugs to try to improve their studies and test performance," Johnston said in a statement. (Amphetamines are stimulants sometimes used to treat ADHD, but they can be abused by people who take the drug, without a prescription, for its ability to increase focus and attention.)
But use of some other drugs appears to be declining. For example, the percentage of college students who said they used synthetic marijuana (also called K2 or spice) during the past year plummeted from 7.4 percent in 2011 to just 0.9 percent in 2014.
The decrease in use occurred along with an increase in the percentage of young people who viewed the drug as dangerous.
The use of narcotic drugs for nonmedical reasons also fell, with 4.8 percent saying in 2014 that they used these drugs during the past year, compared with 8.8 percent in 2006.
Although fewer students are smoking cigarettes, there's been an increase in hookah use: In 2014, 33 percent of college students said they had used a hookah in the past 12 months, up from 26 percent in 2013.
2014 was the first time the researchers asked students about their use of electronic cigarettes. That year, 9.7 percent of college students said they'd used e-cigarettes in the past 30 days. The survey will continue to track changes in e-cigarette use in the future.
The survey, called Monitoring the Future, is given annually to a nationally representative sample of U.S. college students. About 1,000 to 1,500 college students take the survey each year.
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