Are you using — or considering using — marijuana to help with anxiety, pain, muscle spasms, nausea during pregnancy, poor sleep and more? You may be surprised to discover there is little quality evidence on the benefits of marijuana, according to a new analysis of more than 100 clinical trials and meta-analyses.
“After applying very strict quantitative criteria, and accounting for both observational studies and experimental trials, most of the associations between cannabis and health outcomes were supported by very low or low credibility,” said study author Dr. Marco Solmi, associate professor of psychiatry at the University of Ottawa and investigator at Ottawa Hospital Research Institute in Canada.
Much of the most convincing evidence in the study, in fact, pointed to the potential harms of using marijuana, especially for pregnant women, anyone with a mental health disorder and the adolescents and young adults who currently make up the majority of cannabis users.
“If we pair these findings with the fact that almost 2/3 of those with mental disorders have onset before age 25, it sounds reasonable to state that cannabis should be avoided in younger strata of the population,” he said.
The review did find some benefits of cannabis use, particularly with “seizure reduction, chronic pain, and muscle spasms,” said Carol Boyd, founding director of the Center for the Study of Drugs, Alcohol, Smoking & Health at the University of Michigan in Ann Arbor, who was not involved with the study.
However, most studies on seizures, nausea and pain have investigated the impact of carefully made synthetic cannabis or extracts, said clinical pharmacologist Robert Page II, who chaired the medical writing group for the American Heart Association’s 2020 scientific statement on marijuana. Page was also not involved in the study.
Such lab-made cannabis-based drugs have extremely high standards, and may even by regulated by the US Food and Drug Administration, which is not the case with most products members of the public can buy at their local cannabis dispensary, Page said.
“So, from a public health standpoint, I don’t want individuals to read this and say, ‘Oh, I can go down to my dispensary and take care of my pain.’ The answer is no, because the products patients are using in the real world are seldom being evaluated in these studies.”
Where marijuana may harm
Mental health: When it comes to easing the symptoms of anxiety, depression and other mental disorders, the analysis found no benefit. In fact, the opposite is actually true, Solmi said.
Mental health can be dramatically impacted by cannabis, the review found. Using the drug raised the risk of an onset of a psychotic or mental health disorder and using it after the onset of a mental condition worsened clinical outcomes, the study found.
“For instance, in people with psychosis, cannabis increases the risk of relapse, and worsens cognition,” Solmi explained.