U.S. teens smoke more marijuana, but back off other drugs -survey

[RainDog]

22. Aaaand the NYTimes serves up the propaganda

http://well.blogs.nytimes.com/2013/12/18/growing-marijuana-use-among-teenagers-spurs-concerns/?smid=fb-nytimes&WT.z_sma=HL_IMU_20131218&bicmp=AD&bicmlukp=WT.mc_id&bicmst=1385874000000&bicmet=1388638800000&fblinkge0&_r=0

A new federal report shows that the percentage of American high school students who smoke marijuana is slowly rising, while the use of alcohol and almost every other drug is falling.

The report raises concerns that the relaxation of restrictions on marijuana, which can now be sold legally in 20 states and the District of Columbia, has been influencing use of the drug among teenagers. Health officials are concerned by the steady increase and point to what they say is a growing body of evidence that adolescent brains, which are still developing, are susceptible to subtle changes caused by marijuana.

“The acceptance of medical marijuana in multiple states leads to the sense that if it’s used for medicinal purposes, then it can’t be harmful,” said Dr. Nora D. Volkow, director of the National Institute on Drug Abuse, which issued the report. “This survey has shown very consistently that the greater the number of kids that perceive marijuana as risky, the less that smoke it.” Starting early next year, recreational marijuana use will also be legal in Colorado and Washington.

Experts debate the extent to which heavy marijuana use may cause lasting detriment to the brain. But Dr. Volkow said that one way marijuana might affect cognitive function in adolescents was by disrupting the normal development of white matter through which cells in the brain communicate.

I also think it's worthwhile to note that the NIDA will only support/fund research that shows harm from marijuana use.

But what about that growing evidence? Earlier this week, this research made the news: heavy cannabis using teenagers showed changes in the thalmus, mostly. Therefore, according to the NIDA, legal cannabis for adults should be opposed. However, the scientists didn't find the same conclusion that the NIDA did (for today's report). Here's what the scientists had to say -

Smith stressed that it does not prove cause-and-effect, and neither did the PNAS study. The differences in brain geography in Smith’s study could have existed before the young people used weed — it’s possible that their brain differences made them more likely to smoke pot in the first place.

“It’s chicken-and-egg,” explained Donald Dougherty, vice-chair for research and the Wurzbach Distinguished Professor of Psychiatry at the University of Texas Health Science Center in San Antonio.

“We can identify certain differences, mainly in impulse control, related to the onset of substance use,” Dougherty said. “But the key thing is that we do not know what impact drug use has on normal development. It may be that differences at the beginning leads to drug use, then drug use also impacts normal development. We can’t tease these things out.”

Dougherty found the study “very interesting” but agreed with Smith that “there are lots of unanswered questions.” Ideally, researchers would follow children from a time before they ever started using, through a period of use, and into adult years to track brain and cognition changes.

http://www.nbcnews.com/health/teen-pot-use-could-hurt-brain-memory-new-research-suggests-2D11741988

The research had a small sample size, and had no "baseline" brain images to compare - to see if brains in those who heavily used marijuana were altered prior to use.

In 2011, another study with more subjects, that compared alcohol and marijuana with before and after scans over an 18-month period, found that marijuana had no impact upon white matter in the brain, while alcohol did. They also had no "before" brain scans to compare. But they indicated that alcohol created measurable changes related to the same brain regions as the study released this week, while cannabis did not.

Researchers scanned the brains of 92 adolescents, ages 16 to 20, before and after an 18-month period. During that year and a half, half of the teens -- who already had extensive alcohol and marijuana-use histories -- continued to use marijuana and alcohol in varying amounts. The other half abstained or kept consumption minimal, as they had throughout adolescence.

The before-and-after brain scans of the teens consuming typically five or more drinks at least twice a week showed reduced white matter brain tissue health, study co-author Susan Tapert, neuroscientist at University of California, San Diego, told HuffPost. This may mean declines in memory, attention, and decision-making into later adolescence and adulthood, she said.

However, the level of marijuana use -- up to nine times a week during the 18 months -- was not linked to a change in brain tissue health. The researchers did not test performance; they only looked at brain scans.

http://www.huffingtonpost.com/2012/12/21/teens-marijuana-brain-tissue-alcohol_n_2331779.html

...and yet alcohol is legal for adults.