Pubdate: Mon, 29 Apr 2002 Source: Report Magazine (CN AB) Copyright: 2002 Report Magazine, United Western Comm Ltd Contact: http://www.report.ca/ Details: http://www.mapinc.org/media/1327 Note: This is the BC Edition Author: Eli Byfield Bookmark: http://www.mapinc.org/pot.htm (Cannabis) Bookmark: http://www.mapinc.org/mjcn.htm (Cannabis - Canada) POT MAKES YOU, LIKE, SMARTER A Long-term Study Of Its Effects Reaches Surprising Conclusions ANYONE who has tried conversing with a pot-smoker knows why they call it "dope," but the drug's longer-term effects on intelligence may be negligible. According to a study published in the Canadian Medical Association Journal April 2, even heavy marijuana users do not risk permanently reducing their intelligence. Indeed, light users may actually grow smarter. In the late 1970s, the Ottawa Prenatal Prospective Study (OPPS), launched by psychologists at Ottawa's Carleton University, recruited dozens of pregnant, middle-class, Ontario women, some of them pot- and cigarette-smokers. Researchers have followed their children from birth, monitoring their marijuana intake and testing their intelligence every few years. The study relied on a combination of urinalyses and self-reporting to gauge consumption. Intelligence levels were determined through IQ tests. Four of the original 74 were eliminated: two for discrepancies between self-reporting and urinalysis samples, two for ingesting other drugs. The Carleton team administered drug and IQ tests on each subject between the ages of 9 and 12 (before being exposed to marijuana) and between 17 and 20 to determine changes in intelligence. They categorized their subjects as non-users, former regular users, current light users and current heavy users. The universal average for IQ is 100. The entire group averaged 113.8 on their tests as preteens, rising, on average, 2.6 points to 116.4 as young adults. Carleton psychology professor and study director Peter Fried says that the marginal rise was to be expected among normal middle-class teens. However, the IQ of current heavy marijuana users (five or more joints per week) actually dropped from an average 109 as children to about 105 eight years later. "This seems to be only a four-point drop," explains the professor. He counts it as six points, however, because their level should have risen two points. "Current light" pot-smokers (less than five joints per week), surprisingly, underwent a six-point boost on their tests over the years, going from 112 to 118. Prof. Fried stops short of recommending cannabis to students, however. Considering the small sample of light users (only nine) and the 2.6-point increase in non-users, he regards the six-point rise as statistically insignificant. The most interesting of the study's findings was the IQ rise in former users (who had not smoked pot in at least three months). Of nine "formers," five had smoked pot heavily (37 joints per week), but their scores went up roughly four points after they quit. This indicates, thinks Prof. Fried, that "marijuana has no long-term effect on global intelligence." He hastens to add that these statistics were tabulated on teenagers over an eight-year period. They may not apply to longer-term chronic smokers. Also convincing, though, is the fact that former heavy users, averaging 37 joints per week, had smoked considerably more pot than current heavy users, 14 joints per week. "People who smoked five joints per day recovered their IQs within three months," the professor observes. The study is ongoing. Prof. Fried plans to analyze the IQ tests and break them down to reveal the drug's effects on memory and attention. According to him, "There are 12 parts to intelligence. By focusing on certain questions within the IQ tests, we should be able to determine marijuana's influence on each part individually."