Q&A: Does Marijuana Really Cause Brain Shrinkage?

QUESTION:

Hi mary!  Can you tell me more about this study?  I was under the impression that weed was a harmless plant but this is worrying.  I smoke daily for my MS and would rather my brain not shrink!!  I don't smoke to get high and never have.  Ive seen conflicting info.... ppl saying it is/isn't true.  Help!

Anonymous



ANSWER:

Ah, yes.  That study.  If you read beyond the headlines (which many people don't), you'll see that the study is far from conclusive.  To quote the LA Times:

"...the authors of the study acknowledge that they cannot discern whether a pot smoker's smaller orbital frontal cortex is the cause or the result of chronic marijuana use."

Yeah.  Basically, we don't know if the shrunken brains were shrunken before cannabis use.  There's a real possibility that a pre-existing reduction in gray matter could make a person more prone to abuse cannabis, not the other way around.  Unfortunately, we just don't understand the relationship at this time.

Nailing down a singular cause of ANY brain malady is nearly impossible due to all the variables in a person's life.  Does the subject use other substances?  Did they experience childhood trauma?  Lead toxicity?  Head injury?  Drug exposure in the womb?  As with most studies of this kind, the results raise more questions than answers.

As for cannabis being a "harmless plant," not so fast.  Marijuana contains the powerful drug THC, which can have unpleasant side effects in large amounts or in naive users.  Plenty of plants and herbs can kill you, so the idea that natural = safe is deeply flawed.  Still, marijuana has never killed anyone directly, making it safer than the vast majority of drugs including aspirin (which kills about 1,000 people annually).  It's all about weighing the risks and benefits.  If pot helps control your MS, I'd say it's definitely the lesser of two evils. 

Also, try not to worry so much!  Stress can trigger flare-ups of autoimmune diseases like MS.

Sincerely,

Mary Microgram