Recreational marijuana use can cause changes in brain: study



The size and shape of two brain regions involved in emotion and motivation may differ in young adults who smoke marijuana at least once a week, according to a new study published April 16 in The Journal of Neuroscience.

The findings suggest that recreational marijuana use may lead to brain changes even if its lightly or moderately used.

Previous studies exposing animals to tetrahydrocannabinol (THC) — the main psychoactive component of marijuana — show that repeated exposure to the drug causes structural changes in brain regions involved with these functions. However, less is known about how low to moderate marijuana use affects brain structure in people, particularly in teens and young adults.

In the current study, Jodi Gilman, PhD, Anne Blood, PhD, and Hans Breiter, MD, of Northwestern University and Massachusetts General Hospital/Harvard Medical School used magnetic resonance imaging (MRI) to compare the brains of 18- to 25-year olds who reported smoking marijuana at least once per week with those with little to no history of marijuana use. Imaging data revealed they had significant brain differences. The nucleus accumbens — a brain region known to be involved in reward processing — was larger and altered in its shape and structure in the marijuana users compared to non-users.

“This study suggests that even light to moderate recreational marijuana use can cause changes in brain anatomy,” said Carl Lupica, PhD commented to Science Daily. “These observations are particularly interesting because previous studies have focused primarily on the brains of heavy marijuana smokers, and have largely ignored the brains of casual users.”

JOURNAL SOURCE: Society for Neuroscience (SfN). (2014, April 15). Brain changes associated with casual marijuana use in young adults, study finds. ScienceDaily. Retrieved April 20, 2014 from


  • SoulBrother

    are these changes lethal or they just makes you stronger??

  • GSWSyndicate

    Of course cannabis changes the brain….for the better. It protects it from Alzheimer’s, stroke, HIV dementia and numerous other maladies. Why in the world do you think “Just Say No” Ronald Reagan’s admin applied for a patent for all the cannabinoids under the auspices of the Dept Of Human Services? Because science had already proven all that by 1979. The patent was awarded in 1984 and the U.S. govt does indeed have a patent on all the active parts of marijuana (google it if you don’t believe it). These type scare articles are important; but this one was not researched much, in fact it was not researched at all, that is, research to give the public the important parts of “brain changes”. It appears to be a negative starting at the title. Shame shame. It’s time to put down the “cannabis is evil” torch. The USA is headed in a very very different direction than this author, who better hope she receives some of cannabis’ positive changes that are necessary for the endocannabinoid system to thrive. We didn’t even know what the endo system was until around 1990.

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