Using cannabis or cannabinoids can effectively treat chronic pain as well as ease some of the side effects of chemotherapy. However, there also seems to be substantial evidence of an association between cannabis use and the development of schizophrenia, more frequent bouts of bronchitis and an increased risk of motor vehicle crashes, according to a report.
Those conclusions come from a report released Jan. 12 and developed by the National Academies of Sciences, Engineering and Medicine.
The report, “The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research,” contains nearly 100 conclusions related to the health effects of cannabis and cannabinoid use. Cannabis refers to the plant known as marijuana. Cannabinoid refers to medications that contain the chemicals found in the plant.
The researchers examined existing evidence among more than 10,000 studies related to beneficial, harmful or benign effects of cannabis, then listed whether the evidence was conclusive, substantial, moderate, limited or nonexistent.
The researchers examined studies dealing with the use of cannabis in health situations including cancer, respiratory disease, immune function, mental health, heart disease and pregnancy, among others.
The report is one “of the most comprehensive studies of recent research on the health effects of recreational and therapeutic cannabis use,” since 1999, according to the National Academies of Sciences, Engineering and Medicine.
At the time of the study, 28 states and Washington D.C. had legalized cannabis for medicinal usage, Marie McCormick, chair of the committee on the health effects of marijuana, wrote in the report. Eight of those states and Washington D.C. have also legalized cannabis for recreational usage, she wrote, adding “there is a clear need to establish what is known and what needs to be known about the health effects of cannabis use.”
“Having good research is essential so that we know how best we can use it, what are the safest ways, and what are the real risks,” Staci Gruber, said in an online article published Jan. 13 in Business Insider. Gruber is an associate professor of psychiatry at Harvard Medical School and director of the Marijuana Investigations for Neuroscientific Discovery program at McLean Hospital.
Among the report’s conclusions are the following:
• Cannabis use before driving increases the risk of being involved in a motor vehicle accident.
• In adults with chemotherapy-induced nausea and vomiting, oral cannabinoids can reduce those side effects.
• Adults with chronic pain treated with cannabis or cannabinoids likely will experience significantly fewer symptoms.
• Short-term use of oral cannabinoids in adults with multiple sclerosis relieve some of the symptoms of the disease.
• Long-term cannabis smoking could lead to chronic bronchitis.
• Smoking cannabis during pregnancy is linked to lower infant birth weight.
• A statistical association exists between cannabis use and the development of schizophrenia or other psychoses, with the highest risk among the most frequent users.
• Cannabis use likely does not increase the chance for developing depression, anxiety and posttraumatic stress disorder. However, those diagnosed with bipolar disorders who use cannabis daily may experience worsening symptoms of the disorder.
• Moderate evidence shows no link between smoking marijuana and lung cancer.
• No clear evidence exists on whether cannabis use is linked to heart attack, stroke or diabetes.
The report noted that more study is needed, but that some barriers make it difficult to conduct research. For example, researchers have difficulties gaining access to the quantity, quality and type of cannabis product necessary to address specific research questions on the health effects of cannabis use. The researchers suggested more funding be provided by governmental agencies to continue studies.