Marijuana Use Growing Among Teenagers
One out of every 15 high school students smokes marijuana on a near daily basis, a figure that has reached a 30-year peak even as use of alcohol, cigarettes and cocaine among teenagers continues a slow decline, according to a new government report.

The popularity of marijuana, which is now more prevalent among 10th graders than cigarette smoking, reflects what researchers and drug officials say is a growing perception among teenagers that habitual marijuana use carries little risk of harm. That perception, experts say, is fueled in part by wider familiarity with medicinal marijuana and greater ease in obtaining it.

Although it is difficult to track the numbers, “we’re clearly seeing an increase in teenage marijuana use that corresponds pretty clearly in time with the increase in medical marijuana use,” said Dr. Christian Thurstone, medical director of the adolescent substance abuse treatment program at Denver Health and Hospital Authority, who was not involved in the study. Medical marijuana is legal in 16 states, including Colorado, and the District of Columbia.

The long-running annual report, called the Monitoring the Future survey and financed by the National Institutes of Health, looked at more than 46,000 students nationwide. Over all, about 25 percent of 8th, 10th and 12th graders who took part in the study reported using marijuana in the past year, up from about 21 percent in 2007.

R. Gil Kerlikowske, the federal drug czar, said he believed the increasing prevalence of medicinal marijuana was a factor in the uptick. “These last couple years, the amount of attention that’s been given to medical marijuana has been huge,” he said. “And when I’ve done focus groups with high school students in states where medical marijuana is legal, they say, ‘Well, if its called medicine and it’s given to patients by caregivers, then that’s really the wrong message for us as high school students.’”

Mark Baumgartner, the director of inpatient treatment services at the Betty Ford Center, a drug and alcohol rehabilitation center in Rancho Mirage, Calif., said it was “not uncommon” for young adult patients to show up with medical marijuana cards, which can be obtained to treat conditions like chronic pain or migraines.

Marijuana use by teens linked to permanent brain abnormalities later in life, increased schizophrenia risk: study
Smoking a few joints with friends growing up may be the furthest thing from harmless for developing young brains, a new U.S. study suggests.

Teenagers who regularly use cannabis during their adolescent years may cause permanent brain abnormalities by using the drug, and increase their risk of developing serious mental disorders such as schizophrenia, a study published this month in the journal Neuropsychopharmacology, a division of the journal Nature, hints at.

The study, conducted by researchers at the University of Maryland School of Medicine, examined the cortical oscillations in mice. Cortical oscillations (patterns of activity of neurons in the brain believed to underlie various functions) are very abnormal in schizophrenia and in other psychiatric disorders. Scientists exposed young mice to very low doses of the active ingredient in marijuana for 20 days, and then allowed them to return to their siblings and develop normally.

“In the adult mice exposed to marijuana ingredients in adolescence, we found that cortical oscillations were grossly altered, and they exhibited impaired cognitive abilities,” says the study’s lead author, Sylvina Mullins Raver, a PhD candidate in neuroscience and neurobiology at the University of Maryland, in a press release with the study. “We also found impaired cognitive behavioral performance in those mice. The striking finding is that, even though the mice were exposed to very low drug doses, and only for a brief period during adolescence, their brain abnormalities persisted into adulthood.”

When researchers repeated the experiment solely on adult mice, cortical oscillations and ability to perform cognitive behavioral tasks remained normal.

Researchers say this result suggests that mice brains exposed to very low drug doses, and only for a brief period during adolescence, are still affected into adulthood with abnormalities and increased risk of serious disorders.

“Previous research has shown that children who started using marijuana before the age of 16 are at greater risk of permanent cognitive deficits, and have a significantly higher incidence of psychiatric disorders such as schizophrenia. There likely is a genetic susceptibility, and then you add marijuana during adolescence and it becomes the trigger,” says the study’s senior author Asaf Keller, PhD, Professor of Anatomy and Neurobiology at the University of Maryland.

###

Jason Rehel