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."