ICYMI: National Academy of Sciences – Analysis of Evidence for Use of Cannabis

In Case You Missed It:

The National Academy of Sciences out of Washington, DC released a report in January on ‘Health Effects of Cannabis and Cannabinoids‘. The report is a meta analysis of the current body of research on marijuana. It surveys the collection of data and provides recommendations about the strength of the evidence.

The report looks at both the potential benefits – ‘theraputic effects’ – and drawbacks – ‘other health effects’ – of using cannabis. Looking at the current peer-reviewed research, the NAS sorted the findings into three different categories: strong, weak and moderate.

Strong evidence – called conclusive or substantial – has several supportive findings from quality studies with very few or no credible opposing findings. Weak evidence has no or insufficient data to support the association of cause and effect. A moderate level of evidence means that the quality of the research to support the findings was fair, and there was a lack of credible research opposing the findings.

Below are some of the most interesting findings, sorted by weight:

Strong Evidence

• “In adults with chemotherapy-induced nausea and vomiting, oral cannabinoids are effective antiemetics.”¹
• “In adults with chronic pain, patients who were treated with cannabis or cannabinoids are more likely to experience a clinically significant reduction in pain symptoms.”²
• “In adults with multiple sclerosis (MS)-related spasticity, short-term use of oral cannabinoids improves patient-reported spasticity symptoms.”³
• “Smoking cannabis on a regular basis is associated with chronic cough and phlegm production.”⁴
• “Quitting cannabis smoking is likely to reduce chronic cough and phlegm production.”⁵
• “There is substantial evidence of a statistical association between cannabis use and increased risk of motor vehicle crashes.”⁶

Weak Evidence

There is limited data in a quite a few areas, including the immune system, cancer, eating disorders, epilepsy, and spasticity. While we have seen many testimonials from patients in these areas and there are studies forming, the current body of evidence lacks studies with weight:

• “There is insufficient evidence to support or refute the conclusion that cannabinoids are an effective treatment for cancers, including glioma.”⁷
• “There is insufficient evidence to support or refute the conclusion that cannabinoids are an effective treatment for cancer-associated anorexia-cachexia syndrome and anorexia nervosa.”⁸
• “There is insufficient evidence to support or refute the conclusion that cannabinoids are an effective treatment for epilepsy.”⁹
• “There is insufficient evidence to support or refute the conclusion that cannabinoids are an effective treatment for spasticity in patients with paralysis due to spinal cord injury.”¹⁰

Moderate Evidence

In the moderate category of evidence, the analysis suggests that smoking cannabis doesn’t increase your risk for the cancers you would expect of a smoking habit, like lung, head, and neck cancers. The cancer that shows modest evidence associated with consuming marijuana is a subtype of testicular cancer. There is also minimal evidence that use during pregnancy is associated with a higher risk of cancer in your descendants. Judging from the preliminary research, we may want to put some more funding into the results of cannabis consumption on our reproductive organs. Some findings in this category include:

• “There is limited evidence that cannabis and oral cannabinoids are effective in increasing appetite and decreasing weight loss associated with HIV/AIDS.”¹¹
• “There is moderate evidence of no statistical association between cannabis smoking and the incidence of lung cancer.”¹²
• “There is limited evidence of a statistical association between current, frequent, or chronic cannabis smoking and non-seminoma-type testicular germ cell tumors.”¹³
• “There is limited evidence that nabiximols, dronabinol, and nabilone are ineffective treatments for the reduction of depressive symptoms in individuals with chronic pain or multiple sclerosis.”¹⁴
• “There is moderate evidence that cannabinoids, primarily nabiximols, are an effective treatment to improve short-term sleep outcomes in individuals with sleep disturbance associated with obstructive sleep apnea syndrome, fibromyalgia, chronic pain, and multiple sclerosis.”¹⁵

This important analysis of the state of cannabis research was supported by a breadth of American health bodies, at both the national and state-level. Funders include the National Institutes of Health, Oregon Health Authority, Alaska Mental Health Trust Authority; California Department of Public Health; The Colorado Health Foundation; Mat-Su Health Foundation; National Institutes of Health/National Cancer Institute; National Institutes of Health/National Institute on Drug Abuse; and Washington State Department of Health. It was also funded by safety initiatives including the National Highway Traffic Safety Administration; the Robert W. Woodruff Foundation; Truth Initiative; and the U.S. Food and Drug Administration.¹⁶

About the NAS:

“The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, nongovernmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president.”¹⁷