Pubdate: Sat, 26 Nov 2016 Source: Toronto Sun (CN ON) Copyright: 2016 Canoe Limited Partnership Contact: http://www.torontosun.com/letter-to-editor Website: http://torontosun.com/ Details: http://www.mapinc.org/media/457 Author: Postmedia Network Page: 7 T.O. POT HAS QUITE A KICK Missing key chemical that smooths out the buzz: CBC What's in today's weed? It's what's missing that might count the most. The CBC's Marketplace tested the levels of some mind-altering chemicals in marijuana sold in Toronto dispensaries. The strains tested had much more THC - the active ingredient that provides pot's high - than the weed of decades past. Some strains reached as high at 30% THC; much higher than 3%-4% common in pot in the 1970s. But a lesser known chemical called cannabidiol (CBD) couldn't be found at all. CBD is the compound that many scientists believe mitigates the extreme effects of a high, such as anxiety or paranoia, acting as the yin to THC's yang. And it's CBD that many researchers are looking at as a possible treatment for epilepsy, anxiety disorders, schizophrenia, depression, rheumatoid arthritis and other inflammatory diseases. But none of the samples Marketplace tested contained a detectable level of CBD. "It means it's been bred right out of the plant and that's quite remarkable," says Dr. Steven Laviolette, a neuroscientist and one of Canada's top researchers into the effects of marijuana on the brain. If it's missing, that could exacerbate the negative effects people can experience, especially in marijuana with high levels of THC, Laviolette says. "There's basically nothing to put a brake on the psychological and neurophysical effects," he says. There has been an increased focus on increasing THC levels through selective breeding since the '70s, says Jonathan Page, founder of the cannabis-testing firm Anandia Labs and adjunct professor of botany at the University of British Columbia. Page says that "THC is what gives marijuana the bang for your buck," and growers have been breeding plants with higher levels of the chemical. But it has come at a cost. When marijuana is bred to boost levels of THC, the level of CBD naturally decreases because of the way the chemicals interact with one another. The ones most at risk are teens, who've long had access to recreational marijuana. Why? High-THC, low-CBD marijuana doesn't affect a fully developed, adult brain in the same way, Laviolette says. But the developing brain can experience permanent damage on a molecular level, he says. Scientists agree that most critical brain development continues until the age of 25. Canada is expected to legalize recreational marijuana use in the spring. But it's still uncertain whether the levels of THC or CBD will be regulated and labelled on packages of legal weed. - - Postmedia Network Marketplace airs Friday at 8 p.m. The marijuana investigation and other episodes are also available online. - --- MAP posted-by: Matt