Welcome to DU! The truly grassroots left-of-center political community where regular people, not algorithms, drive the discussions and set the standards. Join the community: Create a free account Support DU (and get rid of ads!): Become a Star Member All Forums Issue Forums Culture Forums Alliance Forums Region Forums Support Forums Help & Search

RainDog

(28,784 posts)
29. A larger study from 2011 showed no cognitive harm
Mon Dec 16, 2013, 07:32 PM
Dec 2013

The study in the OP was comprised of 44 people with 10 people as a control. A larger study showed that, when controls for educational level and gender were included, there were no differences.

From 2011-

researchers followed nearly 2,000 young Australian adults for eight years and found that marijuana has little long-term effect on learning and memory— and any cognitive damage that does occur as a result of cannabis use is reversible.

Participants were aged 20-24 at the start of the study, which was part of a larger project on community health. Researchers categorized them as light, heavy, former or non-users of cannabis based on their answers to questions about marijuana habits.

...Participants took tests of memory and intelligence three times over the eight year period the study. They were also asked about how their marijuana use had changed. When the results were at last tabulated, researchers found that there were large initial differences between the groups, with the current marijuana smokers performing worse on tests that required them to recall lists of words after various periods of time or remember numbers in the reverse order from the one in which they were presented.

However, when the investigators controlled for factors like education and gender, almost all of these differences disappeared. The lower education levels of the pot smokers — and their greater likelihood of being male — had made it look like marijuana had significantly affected their intelligence. In fact, men simply tend to do worse than women on tests of verbal intelligence, while women generally underperform on math tests. The relative weighting of the tests made the impact of pot look worse than it was.

http://healthland.time.com/2011/07/19/study-marijuana-not-linked-with-long-term-cognitive-impairment/#ixzz2ngR771p5

The conclusion from the researchers was:

The adverse impacts of cannabis use on cognitive functions either appear to be related to pre-existing factors or are reversible in this community cohort even after potentially extended periods of use. These findings may be useful in motivating individuals to lower cannabis use, even after an extensive history of heavy intake.

So, given this result, which substances are positives? Coyotl Dec 2013 #1
Peabut butter and toast is safe, in moderation /nt Bragi Dec 2013 #3
Without my glasses, I first read that as "and masturbation" deurbano Dec 2013 #5
Also hairy palms /nt Bragi Dec 2013 #15
The pot criminalisation crowd will cheer, but so what Bragi Dec 2013 #2
Previously Discredited billhicks76 Dec 2013 #23
I read it immediately as another scare tactic. As another poster said, it's based RKP5637 Dec 2013 #27
As acknowledged in the article, the evidence is correlational. Jackpine Radical Dec 2013 #4
+1, n/t RKP5637 Dec 2013 #28
" young heavy marijuana users" SCVDem Dec 2013 #6
Exactly, moderation should be stressed! Criminalization is so backward and RKP5637 Dec 2013 #32
"NEW" ??? RitchieRich Dec 2013 #7
So keep imprisoning those teenagers! JackRiddler Dec 2013 #8
Confirms other studies musiclawyer Dec 2013 #9
actually, it doesn't confirm other studies RainDog Dec 2013 #25
This doesn't confirm shite TheSarcastinator Dec 2013 #55
And...what is the precentage of brain damage done by football playing teenagers? Lint Head Dec 2013 #10
Damn, I could have been so much smarter. maxsolomon Dec 2013 #11
Any psychoactive drug will alter the way a brain develops. intaglio Dec 2013 #12
"will have easier access"? eggplant Dec 2013 #13
winner! pipoman Dec 2013 #42
This is a scare piece RainDog Dec 2013 #45
Actually, it doesn't indicate anything. eggplant Dec 2013 #48
can you elaborate? RainDog Dec 2013 #49
I apologize eggplant Dec 2013 #50
okay. I was confused RainDog Dec 2013 #58
More legal, less use. MORE LEGAL, LESS USE! Festivito Dec 2013 #14
It's the same with alcohol... EC Dec 2013 #16
I suggest that pot makes you smarter...... Bennyboy Dec 2013 #18
Right on the money! GliderGuider Dec 2013 #57
Not to advocate pot use for underage kids but what else were the kids... Ganja Ninja Dec 2013 #17
Like... Contact sports? truthisfreedom Dec 2013 #19
Other studies show that pot protects the brain from damage bananas Dec 2013 #31
What the heck is a "heavy user who has not indulged for more than 2 years" ? KurtNYC Dec 2013 #20
You may not like this…but this is really true about these young ones and is beyond sad... Tikki Dec 2013 #21
Who cares , nobody is going to remember this study was even done. Leontius Dec 2013 #22
What study? Inkfreak Dec 2013 #35
Last week a Harvard study indicated NO correlation between Teen use and Schizophrenia RainDog Dec 2013 #24
"Brain structural studies often...capitalize on the ones that are significant by chance" bananas Dec 2013 #26
A larger study from 2011 showed no cognitive harm RainDog Dec 2013 #29
No long-term harm. Igel Dec 2013 #38
Maybe the problem is poverty itself RainDog Dec 2013 #40
I'll say what I always say, if pot gives you schizophrenia, don't smoke pot. tridim Dec 2013 #30
Overview of recent studies RainDog Dec 2013 #33
I forgot why I clicked this link.. Inkfreak Dec 2013 #34
Oops. Maybe this is why my memory is so bad right now at 50-years-old! Maybe I didn't smoke much BigDemVoter Dec 2013 #36
I'm a little teen pot dipsydoodle Dec 2013 #37
You don't want to see my spout! SCVDem Dec 2013 #39
I can't remember if my teenage pot use calguy Dec 2013 #41
So if making it legal pipoman Dec 2013 #43
LOL. I didn't read down the thread RainDog Dec 2013 #46
And something like teens binge drinking is a good thing? n/t freethought Dec 2013 #44
In places with legal cannabis, traffic accidents have decreased RainDog Dec 2013 #47
Portugal 11 years after drug decriminalization kristopher Dec 2013 #51
I agree with this study cap Dec 2013 #52
good! TheSarcastinator Dec 2013 #54
It's the return of Reefer Madness!!! TheSarcastinator Dec 2013 #53
Bullshit! wildbilln864 Dec 2013 #56
Latest Discussions»Latest Breaking News»Teen pot use could hurt b...»Reply #29