New Marijuana Study

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Since ancient times, people have been singing the praises of medical marijuana.  However, according to a recent study, this might not actually be the case.  The study, published in the Journal of Neuroscience, Jointis the first link to casual marijuana use to major brain changes.  According to the researchers, the degree of abnormalities is based on the number of joints you smoke in the week.  Using different types of neuroimaging, researchers examined the brains of some 40 people between the ages of 18 and 25 who were enrolled in colleges in the Boston area.  20 of them smoked marijuana at least once a week, while the other 20 never did.

The marijuana smokers were then asked to track their drug use for 90 days.  All were given high-resolution MRIs, and the results of users and non-users were compared.  Researchers examined the regions of the brain involved in emotional processing, motivation and reward, called the nucleus accumbens and amygdala.  They analysed the volume, shape and density of grey matter, which is where most cells in brain tissue are located.  According to Dr. Jodi Gilman, lead author of the research and a researcher in the Massachusetts General Center for Addiction Medicine, the findings show that marijuana use causes observable differences in brain structure, which indicates significant effects of marijuana on the brain.  These differences were exposure-dependent, so those who used marijuana had greater abnormalities.

More than a third of the group, seven of the 20, only used pot recreationally once or twice a week.  The median use was six joints a week, while four people in the study smoked more than 20 joints a week.  None of the users reported any problems with school, work, legal issues, parents or relationships.  According to Dr. Hans Breiter, co-senior author of the study, the results of the study reveal that we should be much more careful about the legalization process.  For a long time, researchers have been concerned about the effects of marijuana on developing brain-teens and adolescents under the age of 25.  Preliminary research revealed that early onset smokers are slower at tasks, have lower IQs later in life and even have a higher risk of stroke.  The one piece of advice that all researchers seem to agree upon is to not do marijuana at too early an age.  Regular use of marijuana prior to 16 is associated with greater difficulty of tasks that require judgment, planning and inhibitory function, as well as changes in brain function and white matter microstructure relative to those who start later.

According to the National Survey on Drug Use and Health, in 2012 nearly 19 million Americans used marijuana.  It’s the most-used illegal drug in the country, and its use continues to grow amongst teenagers and young adults.  Results of this new study match those of animal studies, which show that when rats are given THC (the active ingredient in marijuana that gets you high), their brains rewire and new connections are formed.  With this study, the next important thing to look at is how structural abnormalities relate to functional outcomes.  We currently have no idea how much marijuana is safe, and this study, according to the researchers, reveals that we need to be cautious about marijuana use in adolescents and young adults in whose developing brain may be susceptible to changes.


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