Smoking 3,000 Joints Is Bad for Your Brain, Study Finds

(Nov. 16) -- This news may be something of a buzz-kill.

A new study shows that subjects who began smoking pot before age 16 scored significantly worse on cognitive function tests than both nonsmokers and those who picked up the habit later in life.

The research, presented Monday at the annual Society for Neuroscience meeting in San Diego, analyzed tests performed on 33 chronic marijuana smokers -- the scientific term for "stoner" -- and 26 nonsmokers. Lead researcher Staci Gruber and her team from the Harvard-affiliated McLean Hospital found that chronic smokers demonstrated an inability to retain a set of rules and repeated errors more frequently than the nonsmokers. (One wonders whether this explains why California failed to pass Proposition 19.)

"Even before any behavioral differences, we found that those who started smoking before 16 years old tended to smoke twice as often and three times the amount of marijuana in grams than chronic smokers who started smoking later in life," Gruber said.

According to ABC News, "Researchers defined chronic marijuana use as smoking pot at least five of the last seven days and a minimum of 3,000 joints in a lifetime."

Your reaction to this definition may be similar to that of Gawker's Max Read:

"Three thousand joints! That's maybe not such a big deal to old hippies, but the average age of study participants was 22. So, participants who started smoking at age 18 would have had to smoke about two joints a day to be defined as 'chronic,' and those who started smoking at 16 would be sparking about 10 joints a week, every week, since that time. (How's that for cognitive function, science?) Which isn't impossible, obviously! But that's a rather high bar for 'chronic,' isn't it?"

Cheech and Chong might have reason to be concerned, but it's going to take a lot of "South Park" episodes and Pink Floyd albums for the average high school stoner to make up all that ground before turning 22.

Of course, Gruber and her colleagues intentionally studied habitual marijuana smokers, admitting that further research would be required before drawing conclusions on those who only indulge occasionally.

"It's impossible to tell whether our results would be the same in moderate smokers," Gruber said. "But there are even more of those people out there, so that will be the next place we go for our research."

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