Evidence-Based Reviews

Risks of increasingly potent Cannabis: The joint effects of potency and frequency

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Recommendations for clinicians

Similar to any drug, the effects of THC and its psychiatric sequelae can be expected to increase with dosage. To date, much of the information about psychiatric risks has been based on studies of low- and moderate-potency Cannabis rather than the much higher potency Cannabis products, such as hyper-concentrated “wax dabs,” that are available today. Data from social media suggest that these products may be associated with novel patterns of use, such as with the intention of “passing out.”41 It is likely that clinicians will encounter greater psychiatric morbidity associated with HPC use.

Although clinicians may be accustomed to asking about the frequency and duration of Cannabis use, it is now prudent also to ask patients about Cannabis potency to better assess the potential risks of use. The potency of different marijuana products is openly advertised within some “medical marijuana” dispensaries, although the accuracy of information in products such as “edibles” has been called into question.5

Physicians are increasingly asked to provide recommendations on “medical marijuana” use. A recent paper outlined characteristics of appropriate candidates for “medical marijuana” including:

  • having a debilitating condition that might benefit from Cannabis
  • multiple failed trials of conventional pharmacotherapies including FDA-approved cannabinoids
  • lack of substance use disorders, psychosis, or unstable mood or anxiety disorders
  • residence in a state where “medical marijuana” is legal.42

As part of the informed consent process, physicians providing recommendations for “medical marijuana” now must consider the effects of HPC when weighing potential risks against any benefits of Cannabis use. Those monitoring patients using Cannabis should be aware of the potential for greater psychiatric morbidity with HPC and should educate patients about that risk. Failure to adequately warn patients about such morbidity or to screen for risk factors such as psychosis could leave physicians vulnerable to malpractice litigation.

Bottom Line

Cannabis potency has risen significantly over the past several decades, with available evidence pointing to an increased risk of Cannabis use disorder, psychosis, acute cognitive impairment, and structural brain changes with use of high-potency Cannabis. Clinicians should consider asking patients who use marijuana about potency to better assess risk of psychiatric adverse effects.

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