Almost one-quarter of the nation’s high school seniors say they have smoked marijuana in the past month, and just over 36 percent admit to using the drug in the past year, according to the 2012 Monitoring the Future Survey . Researchers at the University of Michigan who conducted the annual survey found 6.5 percent of high school seniors smoked marijuana daily.
Among 10th graders, 3.5 percent say they use marijuana daily, while 17 percent report using the drug in the past month, and 28 percent in the past year. “We are increasingly concerned that regular or daily use of marijuana is robbing too many young people of their potential to achieve and excel in school or other aspects of life,” National Institute on Drug Abuse Director Dr. Nora D. Volkow said in a news release . “THC, a key ingredient in marijuana, alters the connectivity of the hippocampus a brain area related to learning and memory. In addition, we know from recent research that marijuana use that begins during adolescence can lower IQ and contribute to reduced cognitive abilities during adulthood.”
The survey of approximately 45,000 eighth, 10th and 12th graders found fewer students perceive marijuana as harmful, compared with previous years, Bloomberg.com  reports. Researchers found 41.7 percent of eighth graders view occasional use of marijuana as dangerous, and 66.9 percent view regular use as harmful. These rates are the lowest since the survey began asking this age group about their perceptions of marijuana in 1991.
Among 12th graders, 20.6 percent view occasional marijuana use as risky, the lowest rate since 1983. Among this age group, 44.1 percent view regular use as harmful, the lowest rate since 1979.
“Yet another year of increases in childhood marijuana use is deeply disturbing as these can spell real trouble for young kids later on,” Steve President and CEO of The Partnership at Drugfree.org said in a statement . “Heavy use of marijuana – particularly beginning in adolescence – brings the risk of serious problems and our own data have shown it can lead to involvement with alcohol and other drugs as well. Kids who begin using drugs or alcohol as teenagers are more likely to struggle with substance use disorders when compared to those who start using later in life. This is of particular concern because we know that 90 percent of addictions have roots in the teenage years.”
The survey found use of other illicit drugs continued declining among high school students.