Known health effects of marijuana from extensive study review

Kathleen Blanchard's picture
Marijuana health effects reviewed

Here are the results of a review of research of the good and not so good health effects of cannabis from the National Academies of Sciences, Engineering, and Medicine that you can read in twenty seconds.


The review includes marijuana and active cannabinoid compounds.

Reviewers for the study highlight the importance of firmly reviewing evidence about the therapeutic effects and potential harm of cannabis that should be further studied for clarity.

Marijuana positive health effects

  • Cannabis and cannabinoids significantly help treat chronic pain
  • Man-made cannabinoid medications help relieve muscle spasm related to MS
  • Oral cannabinoid medications conclusively help relieve nausea and vomiting from chemotherapy

The bad

  • Per the review, there is “moderate” evidence linking marijuana to substance dependence or abuse including alcohol, tobacco and illicit drugs.
  • Marijuana causes impaired memory, learning and attention immediately after use.
  • Smoking cannabis during pregnancy is linked to lower birth weight
  • Strong evidence frequent marijuana use is tied to schizophrenia
  • Increased chance of having a motor vehicle accident while under the influence of THC.
  • Smoking pot can lead respiratory ailments such as chronic bronchitis. Some evidence suggests a risk for lung cancer.


Still, much is unknown. For instance, the reviewers found limited evidence for other health effects of marijuana such as treatment of PTSD or improved appetite for those suffering from chronic health conditions such as HIV.

There is also no hard core evidence that marijuana makes people antisocial, unemployable or academic underachievers.

Researchers for the review say we still don’t know enough about the health effects of marijuana because funding for studies is limited - and needed. Also, marijuana has been classified as a schedule I drug, which impedes research.


National Academies of Sciences, Engineering, Medicine

Updated 2/27/2017