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In reply to the discussion: Teen pot use could hurt brain and memory, new research suggests [View all]RainDog
(28,784 posts)29. A larger study from 2011 showed no cognitive harm
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.
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.
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I read it immediately as another scare tactic. As another poster said, it's based
RKP5637
Dec 2013
#27
And...what is the precentage of brain damage done by football playing teenagers?
Lint Head
Dec 2013
#10
You may not like this…but this is really true about these young ones and is beyond sad...
Tikki
Dec 2013
#21
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
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