Medical marijuana, or cannabis, has been legalized in 28 states, including Connecticut, and recreational marijuana is available in 7 states and the District of Columbia. Recreational and medicinal cannabis use has increased 45% in the general population since 2007. In states that allow medical marijuana, the most widely recognized qualifying diagnoses include cancer, HIV, multiple sclerosis, glaucoma, seizure and pain. With its wide spread availability, what is actually known about its biological effects?Unfortunately, evidence regarding its health and therapeutic benefits are surprisingly scant. This year, the National Academies of Science, Engineering, and Medicine released its third comprehensive review of the literature concerning the health effects of cannabis. The committee found that among adults with chronic pain, those treated with cannabinoids (active chemicals derived from marijuana) had a modest improvement in pain compared to placebo. Similarly, in MS, there was a modest improvement in spasticity compared to placebo. In neither case were the cannabinoids compared to other established effective treatments, like Ibuprofen or Tylenol for pain. The control group in these studies only received placebos. Oral cannabinoids also have a modest benefit in chemotherapy induced nausea and vomiting. Overall the committee found a lack of evidence to support marijuana’s use for most of its stated approved indications.
The use of cannabis also presented worrisome side effects. The committee found an association with cannabis use and respiratory complaints including chronic obstructive lung disease and acute bronchitis. Recent evidence also linked marijuana to coronary artery disease. Cannabis use has also been associated with low birth weight in infants, poor achievement in school and/or work, difficulties in social situations, and motor vehicle accidents. Problems with its use are generally linked to marijuana’s euphoric effect and to its being inhaled. The committee recommended high quality studies using non euphoric, orally administered preparations to define more clearly possible therapeutic indications.