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NLM Director’s Comments Transcript
Marijuana’s Clinical Risks, Benefits, and Uncertainties: 03/31/2014

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Just say no poster with 2 joints forming the letter x.

Greetings from the National Library of Medicine and MedlinePlus.gov

Regards to all our listeners!

I'm Rob Logan, Ph.D. senior staff National Library of Medicine for Donald Lindberg, M.D, the Director of the U.S. National Library of Medicine.

Here is what's new this week in MedlinePlus.listen

Some evidence about marijuana’s clinical risks, benefits, and uncertainties are summarized by one of the nation’s leading physician-authors in an essay recently published in the New York Review of Books.  

Jerome Groopman, M.D., Harvard University Medical School, notes there is recent clinical evidence regarding marijuana’s health risks, benefits, tradeoffs, as well as uncertainties. Dr. Groopman, who often writes about biology, health, and medicine for lay audiences, adds the supporting evidence on all sides is important in view of current efforts to make marijuana legal for medicinal and/or recreational use across the U.S.

Currently, marijuana is available for medicinal use in 20 U.S. states and the District of Columbia. Colorado now permits the sale of marijuana for recreational use (in small quantities). The state of Washington also will permit the sale of marijuana (or cannabis) for recreational use (also in small quantities) for the first time this spring.

Dr. Groopman, an internist, reports two systematic reviews (involving about 6,100 patients with a variety of medical conditions) suggest marijuana is useful to treat a number of diseases and conditions including: anorexia, nausea and vomiting, glaucoma, and irritable bowel disease. Marijuana also is clinically useful to treat: muscle spasticity, multiple sclerosis, epilepsy, Tourette’s syndrome, and symptoms of ALS (Lou Gehrig’s disease).

However, Dr. Groopman emphasizes there is a tradeoff of health risks versus benefits from marijuana use — similar to other medical drugs and procedures. For example, he notes current evidence suggests marijuana’s clinical risks include: decreased reaction time, reduced attention and concentration, a decline in short term memory, and an ability to assess external risks.

Dr. Groopman, who is a member of the Institute of Medicine, adds one study found marijuana impaired the performance of pilots on a flight simulator for as much as 24 hours. Similarly, Dr. Groopman notes studies on drivers suggest a strong association between cannabis and collisions. He adds research suggests drivers who use marijuana are two to seven times more likely to be responsible for accidents compared to motorists who do not use drugs or alcohol.

In addition, Dr. Groopman reports some evidence suggests a statistical association between marijuana use and the development of schizophrenia and other psychosis later in life. Dr. Groopman reports these findings are based on meta-analyses (from studies of the health records of young persons in Sweden, New Zealand, and Holland, who did and did not smoke marijuana).

Dr. Groopman explains the latter research does not suggest there is a causal link between marijuana use and psychosis’ development. Dr. Groopman, who has published five books about health and medicine, argues the state of current evidence suggests a need for more definitive research (via double blind, randomized, placebo-controlled approaches) to better assess the possible relationship between marijuana and psychosis’ development.

Moreover, Dr. Groopman notes there is some evidence that marijuana is associated with possible addiction and compulsive cravings that foster user dependence. Nevertheless, he reports other street drugs, such as cocaine or heroin, seem to retain comparatively higher risks of user addiction and dependence than marijuana.

Dr. Groopman continues the current evidence is somewhat equivocal about marijuana’s impact on pain reduction. He writes (and we quote): “While chronic pain seems amenable to amelioration by marijuana, its impact on reducing acute pain, such as after surgery, is minimal’ (end of quote).

Overall, Dr. Groopman explains if the arguments of marijuana’s critics and supporters are assessed through a clinical research perspective, some positions may not be supported by a robust evidence-base, some positions may be one-dimensional, and others might or might not be sustained. He concludes (and we quote): ‘.. as more studies are conducted on marijuana for medical or recreational uses, opponents and enthusiasts may both discover that they were neither entirely right nor entirely wrong’ (end of quote). 

The essay, which includes a review of recent books about marijuana’s health risks and benefits, can be found at: nybooks.com.

Meanwhile, a website (from the National Institute on Drug Abuse) devoted to the topic whether marijuana is or is not medicine is available in the ‘related issues’ section of MedlinePlus.gov’s marijuana health topic page. Some tips for parents about teen and adult marijuana use (also from the National Institute on Drug Abuse) are found in the ‘overviews’ section of MedlinePlus.gov’s marijuana health topic page.

MedlinePlus.gov’s marijuana health topic page also provides links to the latest pertinent journal research articles, which are available in the ‘journal articles’ section. Links to relevant clinical trials that may be occurring in your area are available in the ‘clinical trials’ section. You can sign up to receive updates about marijuana and health as they become available on MedlinePlus.gov.

To find MedlinePlus.gov’s marijuana topic page type ‘marijuana’ in the search box on MedlinePlus.gov’s home page. Then, click on ‘marijuana (National Library of Medicine).’ MedlinePlus.gov also has health topic pages on drug abuse and substance abuse problems.  

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It was nice to be with you. I look forward to meeting you here next week.