Marijuana Law, Policy & Reform

Editor: Douglas A. Berman
Moritz College of Law

Tuesday, December 17, 2013

What are the best and worst drugs for daily use by teens?

The title of this post is the (perhaps silly) question that came to my mind upon reading this new report on some new research headlined "Heavy Pot Use Linked To Memory Loss, Schizophrenia Link."  Here are the basics:

Heavy pot users — smoking marijuana daily for three years — had abnormal changes in their brain structures related to working memory, U.S. researchers say. Lead study author Matthew Smith, an assistant research professor at Northwestern University Feinberg School of Medicine in Chicago, said poor working memory predicts poor academic performance and everyday functioning.

The groups in the study started using marijuana daily at ages 16 to 17 for about three years.  At the time of the study, they had been marijuana free for about two years. Almost 100 subjects participated, including matched groups of healthy controls, subjects with a marijuana use disorder, schizophrenia subjects with no history of substance use disorders and schizophrenia subjects with a marijuana use disorder. The subjects who used marijuana did not abuse any other drugs, the researchers said.

Of the 15 marijuana smokers who had schizophrenia in the study, 90 percent started heavily using marijuana before they developed the mental disorder. Marijuana abuse has been linked to developing schizophrenia in prior research, Smith said.

“The abuse of popular street drugs, such as marijuana, might have dangerous implications for young people who are developing or have developed mental disorders,” said co-senior study author Dr. John Csernansky of Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital.

“This paper is among the first to reveal that the use of marijuana may contribute to the changes in brain structure that have been associated with having schizophrenia.”... The paper was published in the journal Schizophrenia Bulletin.

Modern brain science research has long had me convinced that it would be wise for everyone under the age of 25 to avoid all dangerous substances while their brains are still developing.  Consequently, I am not at all surprised by a finding that daily use of marijuana could hurts developing brains.  I wonder, though, whether it is likely to hurt developing brains more than daily use of alcohol or even some prescription drugs.

That said, I hope the relaxation of modern marijuana laws in many jurisdictions will facilitate a lot more serious scientific research on the various potential harms and benefits of the use and abuse of this widely-used and seemingly widely under-researched drug.

Recreational Marijuana Data and Research | Permalink


Agreed. The absence of any discussion of relative harms is, to my mind, the biggest fault of U.S. drug education programs. Relying exclusively on the criminal code and saying "don't use illegal drugs" gives kids the idea that there are only two categories of drugs, good drugs and bad drugs. The end result has been abuse of prescription drugs and alcohol, which aren't in the bad drugs category.
An interesting experiment is to ask teens to list "drugs." They'll probably reel off 8-10 before they realize alcohol is a drug, if they do at all. Yet here's plenty of evidence showing it too is harmful to the developing brain, perhaps even more so than marijuana.

“[H]eavy drinking may have extensive and far–reaching effects on the brain, ranging from simple ‘slips’ in memory to permanent and debilitating conditions that require lifetime custodial care.” It specifically notes that those who drink heavily over a long period of time “may have brain deficits that persist well after he or she achieves sobriety.”

“Abnormalities have been seen in brain structure volume, white matter quality, and activation to cognitive tasks, even in youth with as little as 1–2 years of heavy drinking and consumption levels of 20 drinks per month, especially if >4–5 drinks are consumed on a single occasion. Heavy marijuana users show some subtle anomalies too, but generally not the same degree of divergence from demographically similar non-using adolescents.”

Posted by: Dan Riffle | Dec 18, 2013 2:46:12 PM

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Posted by: GoTracts | Dec 19, 2013 7:04:13 AM

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