Landmark Report Weighs in On Marijuana's Health Effects


A new report released by the National Academies of Sciences, Engineering, and Medicine (NAS) sets forth an objective offering of key evidence surrounding the benefits and harms of cannabis use.

As more proponents push for the legalization of marijuana in the United States, there is a greater urge for further research into how cannabis affects an individual's health. A new report released by the National Academies of Sciences, Engineering, and Medicine (NAS) sets forth an objective offering of key evidence surrounding the benefits and harms of cannabis use.

The Health Effects of Cannabis and Cannabinoids: Current State of Evidence and Recommendations for Research is the NAS’s first comprehensive marijuana report since 1999. It lays out substantial evidence that associates the use of cannabis with the development of psychoses and schizophrenia, but also provides studies that show its potential benefits, such as relief of chronic pain and chemotherapy-induced nausea. The NAS committee noted that certain barriers, including the Schedule 1 classification, impedes scientists from gaining a more extensive understanding of the substance.

The NAS committee focused on compiling high quality research and systematic reviews conducted from 2011 to 2016 with several health endpoints including: therapeutic effects, injury and death, cancer, heart attack, stroke, diabetes, respiratory disease, immunity, mental health, problem cannabis use, cannabis use and the abuse of other substances, psychosocial issues, and prenatal, perinatal, and neonatal exposure.

Although evidence indicates that cannabis is likely to increase the risk of mental health problems, such as schizophrenia, social anxiety, and depression, little is known about the actual causality. The report also showed a link between greater frequency of cannabis use and cannabis use at an early age and an increased risk of developing problem cannabis use.

However, the strongest data supported marijuana’s beneficial effects. Some of the key benefits included:

  • Relief of chronic pain, chemotherapy-induced nausea and vomiting, and improvement of multiple sclerosis spasticity
  • Improvement of short-term sleep in patients with obstructive sleep apnea, fibromyalgia, chronic pain, and multiple sclerosis
  • Potential improvement of anxiety symptoms
  • Increasing appetite and decreasing weight loss in patients with HIV and AIDS

There is no sufficient evidence to link cannabis’ benefits to other conditions, such as cancer, irritable bowel syndrome, epilepsy, amyotrophic lateral sclerosis symptoms, or spinal cord injury-related spasticity.

The report also outlined the potential risks of cannabis use, which included:

  • Worsening of respiratory symptoms and more frequent bronchitis with long-term smoking
  • Increase in motor vehicle accidents
  • Low birth weight in offspring of maternal smokers
  • Higher risk of cannabis overdose in children in states where cannabis is legal

“For years the landscape of marijuana use has been rapidly shifting as more and more states are legalizing cannabis for the treatment of medical conditions and recreational use,” Marie McCormick, chair of the NAS committee, stated in a press release.

In November, 5 states voted to newly legalize recreational marijuana use and 4 states voted to legalize the drug’s medical use. However, marijuana remains a Schedule 1 controlled substance under federal law.

The NAS committee emphasized addressing the challenges and barriers impeding further cannabis research, and recommends more research into the beneficial and harmful effects of the substance. As marijuana becomes more widely accepted and used, a better understanding of the drug’s effects can allow for more appropriate and useful information for its users.


Nearly 100 Conclusions on the Health Effects of Marijuana and Cannabis-Derived Products Presented in New Report [news release]. Washington. NAS Website. Accessed Jan. 13, 2017.

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