I'm not disputing the findings of this study, but based on the bolded sections below, methinks the methodology may be a bit questionable.

Marijuana may affect blood flow in brain
Study suggests users of drug have narrowed arteries
Updated: 4:05 p.m. ET Feb. 7, 2005WASHINGTON - Marijuana users have faster blood flow in their brains, even after a month of not smoking, U.S. researchers reported Monday.



The findings suggest they have narrowed arteries, similar to patients with high blood pressure and dementia, and could help explain reports that heavy marijuana users have trouble on memory tests, said the researchers at the National Institute on Drug Abuse in Baltimore.

Ronald Herning and Jean Lud Cadet tested 54 marijuana users, who smoked anywhere between two and 350 joints a week, and 18 non-smokers.

They used Doppler sonograms to measure blood flow in volunteers’ brains at the beginning of the study and a month later, after everyone agreed to abstain from marijuana for the four weeks.

The smokers had faster blood flow, both at the start and after a month of abstinence, Herning and Cadet reported in the journal Neurology.

The smokers also had a higher pulsatility index score, or PI, which measures the amount of resistance to blood flow. The researchers believe the higher PI is caused by narrower blood vessels.

“The marijuana users had PI values that were somewhat higher than those of people with chronic high blood pressure and diabetes,” Herning said in a statement.

“However, their values were lower than those of people with dementia. This suggests that marijuana use leads to abnormalities in the small blood vessels in the brain.”

They found that blood flow improved in people who smoked up to 70 marijuana cigarettes a week -- people they defined as moderate users -- after a month of avoiding cannabis.

Heavy users, who smoked up to 350 joints a week, saw no change in blood flow even after a month, the researchers said.

Researchers at Montreal’s McGill University have reported that chronic consumers of cannabis lose molecules called CB1 receptors in the brain’s arteries.

This reduces blood flow to the brain, causing attention deficits, memory loss, and impaired learning ability.

OK. There are 168 hrs in a week. So for a person to smoke 350 joints a week they would have to smoke a joint about every 25 min. including waking up in the middle of the night to smoke. Hell to smoke 70 joints a week you would have to blaze up about every hour and a half if you were taking off 7 hrs or so to sleep at night. So where the hell are they finding these iron lungs who were the guinea pigs for this test?

Haha, great observation.

I'm sure the ONDCP is chomping at the bit to use select pieces of this study.

National Institute on Drug Abuse in Baltimore



That alone raises a lot of questions. And yeah, 350 joints a week? C'mon, that's just fucking ridiculous.

jeez, and i thought i smoked a lot. i have some catching up to do

*smokes 5 joints at the same time*

Yeah, you'd have to be chain smokin' those things for a week to finish 350 of'em.

Where do I sign up to see if that can be done?

ooooh, yeah.

"Joints" is such a ridiculous measure of pot intake as well. How big a joint, toothpick or ice cream cone?

Why not measure in terms of "hits". Moderate use being 5-20 hits a day (aka 1-3 joints).

--PunkDavid (good god, I want to get high)

well "hits" would be tough too cause bong hits are much bigger than joint or bowl hits. then you have to take into account how big the hit your taking is. Is it one of those pussy hits or one of the ones that makes you cough so much you drool all over yourself and your lungs are on fire.

Do you think they'd accept the scientific term "bongload" defined as "the smoke ingested from the emptying of a one-hitter bowl of high-quality marijuana through a single chamber waterpipe"?

--Dr. PunkDavid, lsD

You have epicurean tastes my friend, and seriously, you knowledge of the bong astounds me.

I swear, you were BORN to be a lawyer.

-Sunny

Any "scientific" study not published in a respected, peer-reviewed journal is useless. Even some of them are still deserving of criticism.

My neurologist told me:

"Marijuana is basically a muscle relaxer"

And if there was any chance that pot affected the vascular action in the brain, he would know about it (he's a migraine expert AND from the Netherlands) and he would have told me to not smoke it. People with migraines are VERY sensitive to anything that fucks with the blood vessels in the brain.

So I think this is all a load of bullshit. Especially since it is impossible to smoke "350 joints" in one week.

Moderate = 5-20 hits a day?

Yeah this study is like me publishing something that says "Alcohol Causes Short Term Liver Damage" after following around a few guys that took 75 shots of Jack Daniels a day for a few months.

I wouldn't exactly call this study bullshit. I've known people who possibly smoked 70 joints a week and yes, they were a bit slower than the rest of us. I would call the study biased though, since suggesting 70 joints a week is 'moderate' marijuana use is just funny.

*digs into quarter bag that has lasted over a month*

You can function on 5-20 hits a day, therefore I wouldn't classify it as heavy use. I functioned quite nicely on about 7 or 8 hits a day for many years.

--PunkDavid