Heavy marijuana use shrinks brain parts - study

[FrostyMcFailure]

hey now i never said tis harmless, just no where near alcohol in anyway shape or form.. which is legal, sadly.

 

[not special]

I got a copy of the article from my university library. A few quotes from the article.

A cone is a small funnel into which cannabis is packed to consume through a water pipe in a single inhalation. Without the loss of sidestream smoke, the quantity of tetrahydrocannabinol delivered by this method is estimated as equating 3 cones to 1 cigarette-sized joint.

This was hidden in the notes for a table, not in the methods section. It looks like they do have some objective measurements of cannabis use.

Participants were asked to abstain from using for at least 12 hours before each test session, and cannabis users reported abstaining from cannabis for a mean of 21.3 hours before the first test session.

Regarding alcohol use, the groups did not differ in levels of current consumption, life-time use, of history of abuse or dependence; and no participant drank more than 24 standard alcoholic drinks per week. Significantly more cannabis users were also tobacco smokers.

Although modest use may not lead to significant neurotoxic effects, these results suggest that heavy daily use might indeed be toxic to human brain tissue.

They discuss a similar study which found no reduction in hippocampus size in heavy cannabis users (the study is: Lack of hippocampal volume change in long-term heavy cannabis users. Am J Addict. 2005;14(1):64-72). That study used 'heavy users' who used on average a third as much as the users in this study. That suggests to me that you have to smoke a lot of pot before you see these problems.

 

[Christ!]

The most commonly used recreational drug in Australia is alcohol. Which makes me wonder if the study controlled for alcohol use.

How much is "five joints"? There's a huge difference between a joint packed with bud and a weak spliff. Hopefully they had some more objective measurement than that.

In any case this isn't a surprising result. I know pot smokers well under 40 who have completely rooted their brains already. These people were smoking huge amounts of pot for a long time. Heavy drinking is associated with increased dementia and alzheimer's but moderate drinking might actually decrease the risk of dementia. So this study doesn't really say anything about health risks to people who smoke more reasonable amounts.

Really good point. Can't believe I forgot alcohol!