All About Estates

Concerns about Consent for Cannabis Prescriptions in LTC

Last month I wrote about the issue of consent for CPR, explaining that the Court in Wawrzyniak v. Livingstone confirmed that a physician’s duty is to his or her patient and not the interests of the substitute decision-maker (SDM). Treatments that are not believed to be in the interests of the patient and do not meet the standard of care do not need to be offered just because the SDM so desires.

A similar scenario is now being played out in long-term care (LTC) facilities where SDMs are frequently requesting medically prescribed cannabis for patients with behavioural and psychological symptoms of dementia (BPSD).

Current recommendations for the management of BPSD include the judicious use of atypical antipsychotics. However, these treatments have modest efficacy and potentially harmful side-effects, such as increased mortality, Parkinsonism, and adverse cerebrovascular events.[i] Given the extremely distressing nature of BPSD and the limited treatment options available,[ii] caregivers and providers will continue to look for alternative options. It is not surprising that medical marijuana would be considered.

There is some scientific rationale to support the use of cannabis to treat dementia. Cannabinoids act primarily through CB1 receptors, which are particularly common in the hippocampus (Alzheimer’s disease) and basal ganglia (Lewy Body Dementia). Endocannabinoid signaling modulates some pathological processes linked to neurodegenerative processes in mice.[iii]

There have been a few clinical trials in older adults who were given oral synthetic cannabis based drugs with mixed results.[iv] [v] [vi] The consensus appears to be that prospective clinical trials are needed to determine the safety and efficacy of cannabinoids (synthetic and natural) for the treatment of BPSD in dementia. At this time, there remains insufficient evidence for its efficacy.[vii]

Patients with advanced dementia lack the capacity to consent to medical marijuana for BPSD, so it is important to consider how, when, and by whom the decision to use medical marijuana is being made on their behalf. A recent example from my practice in LTC is instructive.

The SDM of a patient with advanced dementia and BPSD was frustrated by my lack of endorsement to pursue medical marijuana. The SDM pursued consultation with the local medical marijuana clinic nonetheless. The SDM informed the nurse practitioner at the clinic that assessment of the patient would not be feasible: the patient could not be brought to the clinic due to the nature of the patient’s behaviour and the nurse practitioner did not provide outreach consultation. Regardless, the nurse practitioner informed the SDM that a prescription would be provided based on the information provided by the SDM. No attempt to obtain corroborative information from our treating team would be necessary. Follow-up assessments would be based on information provided by the SDM only.

I note this suggestion to prescribe medical marijuana for a patient in LTC with advanced dementia and BPSD contravenes our provincial policies on prescribing drugs. The policy of the College of Physicians and Surgeons of Ontario (CPSO) on prescribing drugs states that before prescribing a drug, physicians must undertake an appropriate clinical assessment of the patient. Limited exceptions are made to permit prescriptions on the basis of an assessment conducted by someone else. When relying on someone else’s assessment, physicians must have reasonable grounds to believe that the person who conducted the assessment had the appropriate knowledge, skill, and judgment to do so.[viii] When applied to prescribing cannabis, the policy stipulates that physicians must monitor patients for any emerging risks or complications.[ix] (Bolded words as written are bolded in the CPSO policies.)

The practice of medicine is such that there is no financial gain provided by the drug manufacturer to the treating physician or the dispensing pharmacy for prescribing a drug. This differs from homeopathy, for example, where the prescriber is frequently also the seller. At medical marijuana clinics, once a prescription has been issued, clinic staff help the patient register directly with a licensed producer. If the patient registers with a licensed producer for which the clinic has a contractual arrangement, then a fee is paid to the clinic.[x] So a word of caution to SDMs who demand medical marijuana for patients with advanced dementia and BPSD before we have available evidence of effectiveness and tolerability: Buyers beware!


[i] Schneider LS, Dagerman K, Insel PS (2006) Efficacy and adverse effects of atypical antipsychotics for dementia: Meta-analysis of randomized, placebo-controlled trials. Am J Geriatric Psychiatry 14, 191–210.

[ii] Kales HC, Gitlin LN, Lyketsos CG. Assessment and management of behavioral and psychological symptoms of dementia. BMJ. 2015; 350:h369.

[iii] Aso E., Andres-Benito, P., Isidro Ferrer I. Delineating the Efficacy of a Cannabis-Based Medicine at Advanced Stages of Dementia in a Murine Model. Journal of Alzheimer’s Disease 54 (2016) 903–912.

[iv] Herrmann, Nathan et al. Randomized Placebo-Controlled Trial of Nabilone for Agitation in Alzheimer’s Disease. The American Journal of Geriatric Psychiatry, Volume 27, Issue 11, 1161 – 1173

[v] Liu, C.S., Chau, S.A., Ruthirakuhan, M. et al. Cannabinoids for the Treatment of Agitation and Aggression in Alzheimer’s Disease. CNS Drugs (2015) 29: 615.

[vi] Van den Elsen GA, Ahmed AI, Verkes RJ, Cramers C, Feuth T, Rosenberg PB, van der Marck MA, olse Rikkert GM (2015). Tetrahydrocannabinol for neuropsychiatric symptoms in dementia: A randomized controlled trial. Neurology 84, 285 1-9.

[vii] Maust D. et al, Agitation in Alzheimer’s Disease as a Qualifying Condition for Medical Marijuana in the U.S. Am J Geriatric Psychiatry. 2016 November; 24(11): 1000–1003. doi:10.1016/j.jagp.2016.03.006.





About Dr. Richard Shulman
Dr. Shulman is a geriatric psychiatrist at Trillium Health Partners and is an assistant professor at the University of Toronto. He is medical director of the Capacity Clinic and available for independent medical-legal capacity assessments.


  1. Catharine Williams

    December 31, 2019 - 8:16 pm

    Very interesting (and concerning). Thank you for sharing this information.

  2. Clark Logan

    April 30, 2020 - 8:26 am

    So cool, Thanks for sharing interesting article. Good Job tho.

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