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Marijuana’S Long Term Effects On The Brain Finally Revealed


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With a drug war against marijuana still raging in more countries than not, the question of how long-term marijuana use effects the human brain is a pivotal question in its legalization.  Although alcohol remains legal despite heaps of evidence to the dangers of long-term use, the fight to make marijuana available both with regard to its medical properties (especially in selectively killing cancer cells) and non-medical uses has frequently hinged on the various claims made about marijuana’s effects on the recreational user.

Luckily, the debate can finally move out from the realm of opinion into scientific evidence as researchers from the University of Texas just published their research into the long-term effects of marijuana use on the brain in PNAS (Proceedings of the National Academy of Sciences).

The researcher helped dispel the dying myth that marijuana use lowers IQ, and actually provides more evidence to marijuana’s potential role in fighting Alzheimer’s. The research revealed that earlier onset of regular marijuana use leads to greater structural and functional connectivity in the brain. The most significant increases in connectivity appear as an individual begins using marijuana, with results showing that the severity of use is directly correlated to greater connectivity.

Although these results will need to be confirmed with a larger sample (this was based on roughly 100 participants), the preliminary results seemed promising. More research needed to be done in order to see if these differences are caused by, or simply associated with, long term marijuana use. The UT study also found reduced gray matter in the OFC (orbitofrontalcortex) in long-term users (which is a brain region associated with addiction). It was unclear whether this region is simply smaller in regular users (explaining their regular use) or if the use actually contributed to structural brain changes.

A more recent follow-up study (yes, we edit articles with new information) published in the Journal of Neuroscience, also with 100 people (50 adolescents and 50 adults) found no significant differences in brain structure relating to daily or non-daily cannabis consumption. Which pokes holes in the interpretation that cannabis consumption was the driver in the gray matter differences seen in University of Texas study.

These results will also need to be viewed in light of other researcher showing that cannabinoids actually promote brain cell growth/regrowth (neurogenesis) even in adults. Why this could possibly remain illegal anywhere, is an important question, and hopefully people will continue to inform themselves and others on the topic.

Related Articles on RW: Article Credits: Exposing The Truth

- See more at: http://realitieswatch.com/marijuanas-long-term-effects-on-the-brain-finally-revealed/#sthash.308t2eYi.dpuf

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What are marijuana’s long-term effects on the brain?

 

Substantial evidence from animal research and a growing number of studies in humans indicate that marijuana exposure during development can cause long-term or possibly permanent adverse changes in the brain. Rats exposed to THC before birth, soon after birth, or during adolescence show notable problems with specific learning and memory tasks later in life.19–21 Cognitive impairments in adult rats exposed to THC during adolescence are associated with structural and functional changes in the hippocampus.22–24 Studies in rats also show that adolescent exposure to THC is associated with an altered reward system, increasing the likelihood that an animal will self-administer other drugs (e.g., heroin) when given an opportunity (see “Is marijuana a gateway drug?”). Imaging studies in human adolescents show that regular marijuana users display impaired neural connectivity in specific brain regions involved in a broad range of executive functions like memory, learning, and impulse control compared to non-users.25

The latter findings may help explain the results of a large longitudinal study conducted in New Zealand, which found that frequent and persistent marijuana use starting in adolescence was associated with a loss of an average of 8 IQ points measured in midadulthood.26 Significantly, in that study, those who used marijuana heavily as teenagers and quit using as adults did not recover the lost IQ points. Users who only began using marijuana heavily in adulthood did not lose IQ points. These results suggest that marijuana has its strongest long-term impact on young users whose brains are still busy building new connections and maturing in other ways. The endocannabinoid system is known to play an important role in the proper formation of synapses (the connections between neurons) during early brain development, and a similar role has been proposed for the refinement of neural connections during adolescence. If confirmed by future research, this may be one avenue by which marijuana use during adolescence produces its long-term effects.27

The ability to draw definitive conclusions about marijuana’s long-term impact on the human brain from past studies is often limited by the fact that study participants use multiple substances, and there is often limited data about the participants’ health or mental functioning prior to the study. Over the next decade, the National Institutes of Health is planning to fund a major longitudinal study that will track a large sample of young Americans from late childhood (before first use of drugs) to early adulthood. The study will use neuroimaging and other advanced tools to clarify precisely how and to what extent marijuana and other substances, alone and in combination, affect adolescent brain development.

 

http://www.drugabuse.gov/publications/research-reports/marijuana/how-does-marijuana-use-affect-your-brain-body

Edited by knucklehead bob
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What if people with problems seek out Mj for it's ability to make new connections in the brain and protect the neurons from degradation.  Similar to craving leafy greens if you have low vit. B levels, etc.

I'd hate to be the scientist who puts his/her name on one of these studies if it eventually proves the opposite.  That the cravings are related to underlying problems.  That'd be a terrible cause vs. correlation misinterpretation.

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