April 2014

Marijuana Use Linked to Changes in Brain and Heart Problems

New research links casual marijuana use to both changes in the brain and potential heart problems.

Marijuana, hemp, and cannabis are common names for plants of the genus Cannabis. The term "hemp" is used for Cannabis plants that are grown for nondrug use, such as Cannabis sativaCannabis indica has poor fiber quality and is used to make drugs for recreation and medicine. The major differences between the two are appearance and the amount of delta-9-tetrahydrocannabinol (THC), the active ingredient of marijuana.

In one of two new studies, researchers collected MRI scans on young adults who casually use marijuana as well as on those who report no marijuana use. Various brain measurements were analyzed, including grey matter density, brain volume and shape. The researchers found that marijuana users had greater grey matter density extending through various parts of the brain than those who did not use marijuana. The authors concluded that even casual recreational use of marijuana is associated with changes in the brain.

In a second new study, researchers evaluated the potential link between casual marijuana use and heart problems. All reports of spontaneous heart problems related to marijuana use collected by a French agency from 2006 to 2010 were identified. The researchers found that of the 1979 marijuana-related problems reported, 35 were cases of heart complications and 9 resulted in death. The authors concluded that marijuana should be further reviewed as a potential risk factor for heart problems.

For more information about marijuana, please visit Natural Standard's Foods, Herbs & Supplements Database.


  1. Gilman JM1, Kuster JK, Lee S, et al. Cannabis use is quantitatively associated with nucleus accumbens and amygdala abnormalities in young adult recreational users. J Neurosci. 2014 Apr 16;34(16):5529-38. 
  2. Jouanjus E1, Lapeyre-Mestre M, Micallef J, et al. Cannabis use: signal of increasing risk of serious cardiovascular disorders. J Am Heart Assoc. 2014 Apr 23;3(2):e000638. 
  3. Natural Standard: The Authority on Integrative Medicine. 

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