In response to Dr. Cooper’s letter asking the Canadian Medical Association to support a medical access stream for cannabis,1 I would like to provide some points about medical marijuana to consider in rebuttal.
Distinguishing between chronic pain, concomitant substance abuse and substance dependence alone is very difficult clinically. Substance dependence before, during and after treatment with medical marijuana is common. In one study, the odds of marijuana abuse or dependence were 1.81 times higher (95% confidence interval 1.22–2.67) among residents of states that had legalized medical marijuana.2
Future studies are needed on the consequences of legalizing medicinal marijuana. These include rates of psychosis, accidents, aggression, dropping out of school, HIV and sexually transmitted disease. Other concerns include the effects of licenced cannabis grow operatives that may provide the drug with no or little regulation to patients, decriminalizing recreational cannabis, and physician prescribing for indications that are not based on validated studies.
Cannabis use disorder is a long-term consequence of daily cannabis use that occurs in a large number of daily users of cannabis. It is continued problematic use despite negative consequences; it causes substantial distress or impairment in functioning. Of individuals who use cannabis daily, 25%–50% are reported to develop cannabis use disorder, with cannabis use during adolescence being associated with increased likelihood of the disorder.3 Adolescents also appear to be more vulnerable to brain-based negative effects.3
Treatment with medical marijuana may lead to a higher instance of substance dependence in a patient population that may already be narcotic-dependent at the time of consultation regarding medical marijuana. Careful consideration by government and societal stakeholders regarding the consequences of cannabis use is needed, before wider medical access to cannabis-based treatment can be considered.
Footnotes
Competing interests: Rohit Kumar is a disability adjudicator with the Ministry of Community and Social Services of Ontario.