Recent study links marijuana use to structural brain changes



Post  prepared by Amanda Baker, Drexel University College of Medicine Class of 2014



A study recently published in the Journal of Neuroscience by Harvard researchers have linked casual marijuana use to structural changes in distinct areas of the brain.

These areas, the nucleus accumbens and amygdala, and are largely involved in recognition of reward, motivation, fear, and memory.  In this study, the brain scans of 20 young adult casual marijuana users were compared to those of 20 young adult non-users.

While the results clearly demonstrated significant structural differences between the two groups, the structural changes have not been correlated with consequences in mental or physical functioning.  In other words, researchers aren’t entirely sure of the impact of these brain changes.


Casual marijuana use may damage your brain

The debate regarding the use of marijuana medically and recreationally is ongoing in the United States.

Although the Drug Enforcement Administration(DEA) categorizes this drug as Schedule I, “with currently no accepted medical use and a high potential for abuse”, many argue that there is, in fact, much benefit to medical marijuana, especially in comparison to other sedating pain medications.

This is reflected in 21 state laws which have legalized medical marijuana to varying degrees.

Last summer, Dr. Sanjay Gupta completed a documentary “Weed” highlighting the benefit of medical marijuana:

However, some states such as Washington and Colorado, have gone one step further by legalizing marijuana for both recreational and medical use.

Given the ongoing research on the effects of marijuana, perhaps this new study will call into question continued legalization of the most widely used recreational drug in America.


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The Neurology of Fright Night


Everybody knows October is the month of horror movies, haunted houses and Halloween parades.

But, have you ever wondered why we find fear so exciting?


It turns out that distress and delight are closely related – both are mediated by same deep brain circuit known as the Limbic System.  This system is intimately associated with human emotional behaviors and memory.


The limbic system is highly interconnected with the brain’s pleasure center, responsible for sexual arousal and the “high” derived from recreational drug use,  The Kluver-Bucy Syndrome, caused by bilateral limbic lesioning, includes heightened sex drive and/or a tendency to seek sexual stimulation from unusual or inappropriate objects.


Animals with surgical lesions to the limbic system develop abnormal sexual behaviors

Recent studies  have shown these same circuits are responsible for associating fear with memories and the emotional responses that result from triggering those memories.  Patients affected by the extremely rare genetic condition  Urbach-Wiethe disease can develop selective atrophy of the amygdala, becoming fearless, with little or no emotional response to horror films, large spiders or snakes.

This probably explains why horror movies are most popular with younger audiences, mostly teens and twenty-somethings with raging hormones looking for intense experiences:
teen scary

So, we go to horror movies to be scared, triggering deep seated pleasure centers within the brain, knowing that we’re actually quite safe from harm, because in an hour or two we’re going to walk out of the theater with no permanent harm done.