Medical Cannabis Review Articles and Reports on Adverse Effects

Medical Cannabis Review Articles and Reports on Adverse Effects

The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research
A report published by the U.S. National Academies of Sciences, Engineering, and Medicine.  2017. 
A rigorous review of relevant scientific research published since 1999, summarizing the current state of evidence regarding what is known about the health impacts of cannabis and cannabis-derived products, including effects related to therapeutic uses of cannabis and potential health risks related to certain cancers, diseases, mental health disorders, and injuries.  Sections on evidence of therapeutic effects include: chronic pain, cancer treatment, chemotherapy-induced nausea and vomiting, anorexia and weight loss associated with HIV/AIDS, cancer-associated anorexia-cachexia syndrome, anorexia nervosa, irritable bowel syndrome, epilepsy, spasticity associated with multiple sclerosis or spinal cord injury, Tourette syndrome, amyotrophic lateral sclerosis, Huntington’s disease, Parkinson’s disease, dystonia, dementia, glaucoma, traumatic brain injury/intracerebral hemorrhage, substance addiction, anxiety, depression, sleep disorders, posttraumatic stress disorder, and schizophrenia and other psychoses.  Chapters summarizing evidence of harms include: cancer, cardiometabolic risk, respiratory disease, immunity, injury and death, prenatal/perinatal/neonatal exposure, psychosocial, mental health, cannabis use problems, and abuse of other substances.

Monitoring Health Concerns Related to Marijuana in Colorado: 2014 (No longer available)
Colorado Department of Public Health and Environment.
Changes in marijuana use patterns, systematic literature review, and possible marijuana-related health effects.

Information for Health Care Professionals: Cannabis and the cannabinoids (PDF)
Health Canada. February, 2013.

Endocannabinoid system, clinical pharmacology, dosing, potential therapeutic uses (by condition), precautions, warnings, adverse effects, and overdose/toxicity.

Adverse Health Effects of Marijuana Use
Volkow ND, Baler RD, Compton WM, Weiss SRB.  NEJM 2014;370:2219-2227.
Written by the Director of the National Institute on Drug Abuse and some of her NIDA colleagues, this article is often cited when an author refers to the harms known to come from marijuana use.  Much of the content is seven sections that catalog research demonstrating associations between marijuana use and harms in different domains.  After those seven sections is an important section, “Limitations of the Evidence and Gaps in Knowledge.”  That section starts like this, “Most of the long-term effects of marijuana use that are summarized here have been observed among heavy or long-term users, but multiple (often hidden) confounding factors detract from our ability to establish causality (including the frequent use of marijuana in combination with other drugs).”  It is unclear to what degree the associations listed are relevant to specific types of cannabis extraction products available through the MN Medical Cannabis Program (example: products with similar amounts of THC and CBD vs products with high ratios of THC:CBD or CBD:THC).  And the inability in many (most?) cases of the studies cited to determine whether there is a causal relationship between marijuana use and the observed harm is an important limitation, indeed.

Cannabis: The Evidence for Medical Use
Barnes MP, Barnes JC. Report published by Northumberland, Tyne & Wear NHS Foundation Trust, May 2016.
Literature review and discussion of strength of evidence of effectiveness for a wide variety of medical conditions.  This report was commissioned by the All Party Parliamentary Group for Drug Policy Reform (UK).  The authors note they received no renumeration other than a small grand from the APPG for Drug Policy Reform for their work and that they have no commercial interests in cannabis or cannabis products.  The report includes good discussions of the evidence – or lack thereof – for long-term negative effects often ascribed to marijuana use: psychotic disorders, dependence, respiratory system cancer, cognition, amotivational syndrome, and decreased brain volume.

Adverse effects of medical cannabinoids: a systematic review
Wang T, Collet J, Shapiro S, Ware MA. CMAJ. 2008;178:1669-1678.
Literature review and assessment based on 31 medical cannabis studies that met inclusion and exclusion criteria.

Updated Tuesday, February 19, 2019 at 09:50AM