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Perspectives

Cannabis Use in Older Adults: A Perspective

Solomon, Haley V. DO; Greenstein, Aaron P. MD; DeLisi, Lynn E. MD

Author Information
Harvard Review of Psychiatry: 5/6 2021 - Volume 29 - Issue 3 - p 225-233
doi: 10.1097/HRP.0000000000000289
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Abstract

There has been a dramatic increase in older adults who use cannabis in recent years.1 According to a secondary analysis of data from the National Survey on Drug Use and Health, prevalence of cannabis use increased from 0.4% in 2006 to 4.2% in 2018 in adults aged 65 years and older.2 This substantial increase in older adult cannabis users highlights the differing attitudes and beliefs of the aging Baby Boomer generation in comparison to previous cohorts of older adults, as well as changes in laws making cannabis more readily available.3,4

The cannabis-use patterns of older adults are heterogeneous in terms of age at onset, frequency of use, route of ingestion, and purpose of use. Based on a cross-sectional survey, three patterns of cannabis use were identified in a sample of older adults from Colorado: new users (first cannabis use after age 50), stop-out users (cannabis use stopping between the ages of 31 and 64), and consistent users (cannabis use during all periods of adult life).5 The majority of participants were consistent users (53%). Consistent users were less likely to have a college degree or to be married, and tended to consume cannabis at a high frequency by smoking or inhaling. New users (26%) were predominantly female, more likely to have poor health, ingested cannabis far less frequently than consistent users, and were more likely to use nonsmoking routes of ingestion (vaporizer, capsules, edibles, cream/ointment, liquid tincture, or dabbing). In general, consistent users and stop-out users consumed cannabis for both medicinal and recreational purposes, whereas new users almost exclusively consumed cannabis for medicinal purposes. Another survey recently conducted at a University of California San Diego geriatric medicine clinic had slightly different results, finding that the majority used cannabis for the first time after the age of 60 (61%) and primarily used it for medicinal reasons (78%).6

Other surveys of older adult cannabis users have also found that participants mostly use cannabis for what they perceive to be medicinal reasons, including treatment of pain, insomnia, anxiety, depression, and Parkinson’s disease.7–11 These surveys indicate that cannabis may be perceived by some older adults as a substance now widely available to treat common physical symptoms and improve overall quality of life. However, a 2019 review of cannabis for medicinal purposes for older patients reported that evidence supporting the efficacy for treating pain, insomnia, and mood disturbances is “scanty” and that older adults have an increased risk of side effects from cannabis.12 In fact, various safety concerns in this population have been documented, including drowsiness, dizziness, tachycardia, atrial fibrillation, ventricular arrhythmia, bronchitis, blurred vision, altered judgment, dysphoria or euphoria, anxiety, paranoia or psychosis, and impaired motor coordination.13,14

Unfortunately, few large-scale studies have evaluated the safety and efficacy of either medicinal or recreational cannabis use in this population. Smaller trials have indicated that older adults absorb cannabis at different rates than younger counterparts and tend to experience its effects differently.15,16 Older adults are a discrete population with different needs and concerns than younger adults. Potential health risks are associated with substance use because of age-related physiologic changes, increased number of comorbid conditions, and concomitant use of prescribed medications. Older adults may experience increased susceptibility to adverse drug reactions because of decreased hepatic drug clearance and renal elimination.17 Additionally, cannabis may exacerbate the cognitive-processing speed and visual skills that decrease with aging, which may have particular implications for increasing the risk of falls or other injuries.18,19

With the surge in acceptability and legalization of cannabis, clinicians are being faced with questions regarding efficacy and safety in the elderly. In this Perspectives article, we detail the administration routes, pharmacokinetics, pharmacodynamics, and metabolism of cannabis, as well as pharmaceutical uses, proposed medicinal uses, and special considerations related to the use of cannabis in older adults. We focus on concerns most relevant to the geriatric population, including the impact of cannabis on cognition and on falls and injuries, its drug interactions, and its potential applications in treating behavioral and psychological symptoms of dementia. To our knowledge, these topics have not been explored in depth or included in any up-to-date narrative. The use of cannabis for treating pain, insomnia, anxiety, spasticity, and cancer-related nausea and vomiting has been thoroughly reviewed elsewhere.20–24 Here, we specifically summarize findings from a heterogenous body of literature to inform clinicians about relevant implications of cannabis use in adults aged 65 or older. This article is not an exhaustive review of the literature but rather a summary of the available evidence for concerns relevant to older adults. Of note, although no consensus regarding the definition of older adult emerges from the current literature, older adults will be defined here as individuals aged 65 years and older.25

ROUTES OF ADMINISTRATION, PHARMACOKINETICS, PHARMACODYNAMICS, AND METABOLISM

Knowledge of the pharmacokinetic and pharmacodynamic profile of cannabis is necessary to understand both the proposed therapeutic effects and potential adverse effects. The two most common cannabinoids are Δ-9 tetrahydrocannabinol (THC) and cannabidiol (CBD), which co-occur in the cannabis plant.26 While THC and CBD are frequently consumed together in various ratios, they can also be consumed separately as refined products (e.g., oils, tinctures, and candies).

Δ-9 Tetrahydrocannabinol

When inhaled (from a joint, vaporizer, or other form), THC is rapidly absorbed; measurable serum levels are present moments after it enters the lungs.27 The bioavailability of inhaled THC was found to be 10%–27% in one review28 and 2%–56% in another review;29 with the bioavailability tending to be higher for heavy users and lower for occasional users.28 The discrepant ranges in the two studies reflect uncertain dose deliveries related to smoking dynamics such as depth of inhalation, puff duration, and breath-hold.28,29 THC is lipophilic and circulates bound to plasma proteins.29 THC interacts with cannabinoid receptors 1 (CB1) and 2 (CB2), and passes through the blood-brain barrier, where it initiates its psychoactive effect.27 When eaten, THC is absorbed more slowly and has reduced bioavailability, estimated around 4%–20%.29

Ahmed and colleagues15,16 published clinical trials in 2014 and 2015 assessing the safety, pharmacokinetics, and pharmacodynamics of orally dosed THC in older adults. Those trials found that study participants (average ages = 72.1 and 77.3, respectively) tended to absorb THC at variable rates, compared to young adults who reach their maximum plasma concentration of THC within 60 minutes of consumption. They also found that the older adults tended to have fewer “pharmacodynamic” effects than younger people; namely, participants did not report intoxication, and their vital signs and eyes-open sway scores remained stable. While the older adults demonstrated (statistically) significant changes relative to younger adults in internal perception, body sway with eyes closed, and systolic blood pressure, none of these resulted in adverse events; the authors therefore did not consider the changes to be clinically significant.

Aging is associated with decreased hepatic drug clearance and renal elimination as well as increased body fat and decreased lean body mass, which increases the volume of distribution of lipophilic drugs, including THC.7 Thus, these aspects aging should be taken into consideration when prescribing medications to patients who concurrently use cannabis.

Cannabidiol

CBD is typically consumed orally—as a capsule, drop, or other fat suspension (by contrast, THC, when consumed orally, is typically eaten in food). CBD is also available in topical or transdermal formulations, such as lotions, salves, balms, or patches. CBD is a lipophilic molecule with poor oral bioavailability (as low as 6%).30 CBD is absorbed slowly and may take hours to reach peak plasma concentration.31,32 The CBD that is absorbed and binds serum proteins will enter circulation. How CBD may interact with cannabinoid receptors is still unknown and debated in the literature. To our knowledge, no studies have assessed the safety, pharmacokinetics, and pharmacodynamics of CBD specifically in older adults.

Metabolism of THC and CBD

THC and CBD are metabolized by the cytochrome P450 (CYP450) pathway and UDP-glucuronosyltransferase (UGT). Whether eaten or inhaled, THC undergoes metabolism by the liver and is converted into 11-hydoxy-THC (11-OH-THC) and 11-carboxy-THC (11-COOH-THC).31 11-OH-THC is thought to have better blood-brain-barrier penetration than THC and is therefore more psychoactive.29 THC that is eaten is readily converted into 11-OH-THC, as most of it undergoes first-pass metabolism prior to entering systemic circulation. By contrast, inhaled cannabis is metabolized to 11-OH-THC in smaller quantities since THC reaches a measurable serum level almost immediately after it is inhaled. This difference might explain why edible cannabis is thought to be more potent than inhaled cannabis.

THC is thought to be primarily metabolized by CYP2C9, CYP2C19, and CYP3A4.33 CBD is primarily metabolized by CYP2C19 and CYP3A4 as well as the glucuronidation pathways.31 Both THC and CBD are known to inhibit CYP2D6, and CBD is known to inhibit CYP2C8, CYP2C9, and CYP3A4.34 Similar to smoking cigarettes, inhaling cannabis induces CYP1A2, and the induction effect is additive.35 Given that THC and CBD are hepatically metabolized, the potential for pharmacokinetic drug interactions can be extrapolated based on inhibition or induction of P450 enzymes. One systematic literature review cautioned that medications that are prominent substrates for CYP2C19, CYP2C9, and CYP1A2 are at risk for altered disposition with concurrent usage of cannabis.36 Thus, medications for depression, anxiety, or pain that are substrates for these enzymes—and that are commonly used by the elderly—could be affected by cannabis use, and their effectiveness may either wane or be increased to toxic levels.33,35,37

SPECIAL CONSIDERATIONS IN OLDER ADULTS

Effects of Cannabis on Drug Interactions in Adults Aged 65 or Older

To our knowledge, no studies have specifically assessed interactions between cannabis and other drugs in older adults. In fact, drug interaction information is limited in all age groups.31 Most of the available data either stem from in vitro studies or focus on theoretical interactions related to certain pharmacokinetic or pharmacodynamic properties of cannabis.35,38 For example, in terms of pharmacodynamic interactions, potentiation of sedative effects may occur if cannabis is coadministered with sedatives or hypnotics.39 The increased risk of sedation is important in more vulnerable populations such as older adults.

An example of a particularly relevant interaction for the geriatric population is that of warfarin use.37 Various case studies have reported that cannabis, specifically CBD, increased warfarin blood levels, increased the International Normalized Ratio (INR), a measure of anticoagulation, and thus increased the risk of bleeding.40–43 Cannabis and warfarin are both metabolized by CYP3A4, CYP2C9, and CYP2C19, and in vitro studies have found that smoking cannabis directly inhibits CYP2C9-mediated hydroxylation of S-warfarin.37 Knowledge of this potential interaction is important since warfarin is a commonly prescribed anticoagulant, particularly in the elderly. Furthermore, smoking cannabis induces CYP1A2-mediated metabolism of theophylline and chlorpromazine.33,44 One case report found that cessation of tobacco and cannabis smoking resulted in elevated blood concentrations of clozapine, which is a CYP1A2 substrate.45

Effects of Cannabis on Falls and Motor Vehicle Crashes in Adults Aged 65 or Greater

Older adult falls are a public health concern, with approximately one-third of adults aged 65 or older falling each year.46 Falls are a major cause of injury, functional disability, and morbidity in this population.47 Similarly, motor vehicle crashes (MVCs) can have significant repercussions for older adults, and drivers 80 years or older have the highest rates of driver deaths compared to other age groups.48 Falls and MVCs may be mediated by slowed cognitive processing speed and decline in visual skills, as observed in normal aging.18,19 Other risk factors for injury in this population include lower-extremity sensory impairment, slowed postural reflexes, reduced skeletal muscle strength, and usage of certain medications that may increase the propensity for central nervous system depression, dizziness, and postural hypotension.49,50 Thus, the safety of cannabis use in older adults is of growing concern, given that THC intoxication has been shown to have dose-related reductions in memory, divided and sustained attention, reaction time, and motor function.51

Few of the available studies assess whether cannabis use is associated with an increased number of falls or other injuries in older adults. One study found that cannabis use in adults over age 50 increased the likelihood of emergency department visits due to injury.52 Another study found no increased risk of falls, although dizziness was the most commonly reported adverse event.7 One Phase 1, randomized, double-blind, placebo-controlled, crossover trial assessing 12 healthy patients aged 65 or greater found no differences in body sway scores after administration of oral THC up to 6.5 mg, although patients at high risk of falling were excluded from the study.15 Similarly, another study assessing 18 elderly dementia patients concluded that THC 3 mg had a benign side-effect profile; no participants experienced a fall.53 More data are sorely needed, given the small number of subjects in all these studies and the grave consequences of falls in the elderly.

From adult cohorts, the evidence suggests that cannabis use, particularly intoxication with THC, is associated with impaired driving54 and two times greater risk of serious or fatal MVCs regardless of age.55 Moreover, recreational use has been shown to affect driving ability even when users are not acutely intoxicated.56 In terms of older adults, one prospective cohort study was identified that assessed 600 highly educated, affluent drivers between the ages of 65 and 75 from the Denver metropolitan area.57 No significant association was found between past-year cannabis use and self-reported crashes, although authors noted both that the sample included only a few MVCs and that older drivers may have underreported crashes. Importantly, authors found that past-year cannabis users were four times as likely to drive under the influence of alcohol. Future research examining the relationship between cannabis use and MVC is important since many older adults view their independence as closely linked to driving.

Effects of Cannabis on Cognition in Adults Aged 65 or Greater

The effects of cannabis on aging adults need to be carefully considered, given that the incidence of dementia rises exponentially with age58 and that normal aging is associated with declines in cognitive abilities, including processing speed, and certain memory, language, visuospatial, and executive-functioning abilities.19 A dearth of research focuses on the acute or long-term cognitive effects of cannabis in older adults. One review identified only two studies of adults with a mean age of 65 years or greater, and found no significant differences in various cognitive performance measures between current or former cannabis users and controls.59

Despite the lack of data available for individuals aged 65 or greater, understanding the impact of cannabis on brain health in younger adults may be informative. From adult cohorts, the general consensus is that cannabis use results in acute impairments of attention, learning and memory, and working memory.60–62 It is still contested whether cannabis use results in cognitive deficits that persist after acute intoxication has ceased. Some reviews suggest some short-term and long-term neuropsychological deficits, whereas others find that the effects are undetectable after a period of abstinence.63–69

The impact of cannabis on cognitive function likely depends on the age of cannabis-use onset, frequency of use, duration of use, and length of abstinence.60,70 In adolescence, developments in the brain’s neurochemistry, architecture, and tissue composition are vulnerable to environmental insults such as cannabis, which may affect the normal neuromaturation process.71 In fact, early onset of cannabis use (≤17 years) is associated with greater neurocognitive impairment in multiple domains compared to initiation later.61

The structural and functional changes in the brains of older adults may result in differing cognitive sequalae of cannabis use when compared to younger adults. In older adults, a variety of neurodegenerative processes occur, including decreases in whole brain, temporal, and hippocampal volumes,72 as well as decreased endocannabinoid system function, including decreased CB1 receptor binding and decreased concentration of certain endocannabinoids, such as 2-arachidonoylglycerol (2-AG).73

Interpreting the literature remains challenging because of the lack of focus on adults older than 65, variety of study designs, variable periods of cannabis exposure, differing definitions of abstinence and “long term” cognitive effects, difficulty controlling for premorbid health conditions, and confounding factors such as other substance use, medications taken by the individual, or overall psychopathology.60,74 Thus, further research aimed at identifying the impact of cannabis on cognition in elderly individuals is warranted. Until these studies are conducted, it remains difficult to draw conclusions about the neurocognitive impact of cannabis on adults greater than 65 years old.

PHARMACEUTICAL USES AND PROPOSED MEDICINAL PURPOSES OF CANNABIS IN OLDER ADULTS

Cannabis for Medicinal Purposes

As of February 2020, cannabis for medicinal purposes was legal or decriminalized in 33 states, the District of Columbia, and U.S. territories (Puerto Rico, Guam, and U.S. Virgin Islands).75 After the passage of the Farm Bill of 2018, CBD derived from hemp and containing less than 0.3% THC became federally legal and is largely unregulated in most states.76 The indications for cannabis for medicinal purposes vary depending on individual state laws but include pain, epilepsy, glaucoma, inflammatory bowel disease, irritable bowel disease, Tourette’s syndrome, multiple sclerosis, insomnia, nausea and vomiting related to cancer chemotherapy, loss of appetite and weight loss associated with HIV/AIDS, and various psychiatric conditions such as posttraumatic stress disorder and anxiety.75

In general, evidence-based guidelines for the clinical use and dosing of cannabis for medicinal purposes, especially in older adults, are lacking. Although some authors have suggested THC and CBD dosing recommendations for adults, formal dose-finding studies for medical cannabis have not been conducted.77,78 For THC, an oral dose of 0.15 to 0.30 mg/kg THC is probably sufficient to produce psychoactive effects, but dosing of smoked or vaporized cannabis depends on a variety of factors.13 CBD dose ranges are even less precise, with recommendations loosely ranging from 1 to 50 mg/kg CBD daily, except in the case of the FDA-approved iteration of CBD (Epidiolex), with a recommended starting dose of 2.5 mg/kg twice daily and a maximum recommended dose of 10 mg/kg twice daily.78,79

A more complete discussion of the efficacy of cannabis for medicinal purposes in older adults can be found elsewhere.12,14,80 In summary, the evidence to support the use of medical cannabis in older adults in limited, although selected older individuals may obtain some benefit. The use of cannabis to treat pain is particularly tenuous and remains debated. Authors note that the literature investigating medical cannabis in older adults is composed of low-quality studies with small sample sizes and short intervention durations along with significant variation in cannabis formulation and dosing.80

FDA-Approved Uses of Cannabis

There are three FDA-approved cannabis pharmaceuticals or cannabis-derived products currently available: cannabidiol (CBD), dronabinol (synthetic THC) and nabilone (synthetic cannabinoid similar to THC) (Table 1).79,81–83 The FDA-approved preparations are indicated for treating specific conditions. Cannabidiol (Epidiolex) is approved for seizures associated with Lennox-Gastaut syndrome or Dravet syndrome.79 Dronabinol (Marinol and Syndros) is approved for nausea and vomiting associated with cancer chemotherapy and anorexia associated with weight loss in AIDS patients.81,82 Nabilone (Cesamet) is indicated for nausea associated with cancer chemotherapy.83 None of these preparations has been studied thoroughly in individuals aged 65 or older, and the manufacturers of each drug advise caution in elderly patients. For example, the package inserts for Marinol and Syndros state that elderly patients with dementia are at increased risk for falls, which can be exacerbated by somnolence and dizziness associated with use of the drugs.81,82

Table 1 - Food and Drug Administration-Approved Formulations
Drug Brand name Compound Route Approved for Dose range Geriatric considerations
Cannabidiol79 Epidiolex CBD Solution Lennox-Gastaut & Dravet syndrome Initial: 2.5 mg/kg BID Maintenance: 5 mg/kg BID Max: 10 mg/kg BID Dose selection should be cautious
Dronabinol81,82 Marinol Synthetic THC Capsule (1) Anorexia associated with weight loss in AIDS patients (2) Nausea associated with cancer chemotherapy (1) Capsule
Initial: 2.5 mg QD Max: 10 mg BID (2) Capsule
Initial: 2.5 mg QD Max: 15 mg 4–6 times per day
May be more sensitive to the neuropsychiatric and postural hypotensive effects
Elderly patients with dementia are at increased risk for falls because of their underlying disease state, which may be exacerbated by the CNS effects of somnolence and dizziness of Marinol/Syndros
Dose selection should be cautious
Syndros Solution (1) Anorexia associated with weight loss in AIDS patients (2) Nausea and vomiting associated with cancer chemotherapy (1) Solution
Initial: 2.1 mg QD Max: 8.4 mg BID (2) Solution
Initial: 2.1 mg QD Max: 12.6 mg 4–6 times per day
Nabilone83 Cesamet Synthetic cannabinoid similar to THC Capsule Nausea associated with cancer chemotherapy Initial: 1–2 mg BID Max: 2 mg TID Dose selection should be cautious
Can elevate heart rate and cause postural hypotension
BID, twice daily; CBD, cannabidiol; CNS, central nervous system; QD, once daily; THD, Δ-9 tetrahydrocannabinol; TID, three times daily.

Cannabis to Treat the Behavioral and Psychological Symptoms of Dementia

Behavioral and psychological symptoms of dementia (BPSD) are a constellation of symptoms that include agitation, mood disturbances, aggression, wandering, psychosis, and repetitive vocalizations.84,85 One or more symptoms will affect nearly all individuals at some point in the course of dementia.86 BPSD is associated with earlier nursing home placement,87 increased morbidity, mortality, and hospital stays,88,89 and a decrease in the quality of life of both patients and caregivers.90

No FDA-approved medications are available for BPSD, and off-label use of atypical antipsychotics results in limited clinical benefit with significant side effects and an increased risk of mortality.91–93 Non-pharmacologic interventions, such as person-centered care, caregiver education, habilitative environment, exercise, and various therapies, with the goal of symptom prevention, symptom relief, and reduction of caregiver distress, are considered first-line treatment.94,95 Psychotropics are often used when non-pharmacologic treatment is ineffective, and persons become a danger to themselves or others.95

Given the concerns about safety and efficacy of psychotropics, the endocannabinoid system (ECS) has been suggested as a pharmacologic target to treat BPSD.96 The ECS comprises endogenous cannabinoids and also CB1 and CB2 receptors. CB1 receptors are primarily located in the central nervous system—specifically in the cortex, basal ganglia, hippocampus, and cerebellum. CB1 receptors are also located in the limbic system, including the hypothalamus, whose dysfunction is implicated in the pathophysiology of BPSD.97 Additionally, the ECS has been correlated with modulation of the serotonin and dopamine neurotransmitter systems, which are both implicated in BPSD and the targets of various medications.97 With this mechanism in mind, cannabinoid receptor agonists, such as THC, have been investigated to treat BPSD.98,99

Various cannabinoids have been explored for the treatment of BPSD, including dronabinol,100–103 nabilone,104–107 pure THC,16,53,108–110 and THC/CBD.111 A 2019 systematic review identified six randomized, controlled trials (RCTs), two cohort studies, and four case series that evaluated safety and effectiveness of cannabinoids in treating BPSD.112 Although the observational studies provided encouraging results, no significant benefit was observed in the RCTs. The RCTs included in the review used THC at total daily doses ranging from 1.5–4.5 mg and dronabinol at total daily doses ranging from 2.5–5 mg. The most common adverse reactions were mild. Authors determined that five of the six RCTs were underpowered to detect the effectiveness of cannabinoids in treating BPSD. They also indicated that it was difficult to draw conclusions because of the heterogeneity of studies, differing inclusion criteria between studies, wide range of assessment tools used, and overall poor study quality. A 2019 meta-analysis of six RCTs did not find a significant benefit of cannabinoids over placebo but noted that cannabinoids were associated with a greater risk of sedation and somnolence.113

Since the publication of the review discussed above, one double-blind, crossover RCT found that nabilone resulted in a significant reduction in agitation, with sedation being the most commonly reported adverse effect.105 The trial used a maximum target dose of nabilone 2 mg, which is thought to have comparable pharmacodynamic effects to THC 10 mg, although dose equivalencies have not been formally established.114 Therefore, it has been suggested that lower doses of THC used in earlier RCTs may have been insufficient to observe clinical improvement.112–114 It remains unclear whether using higher-dose preparations may be limited by sedation and somnolence. Additionally, since the review was published, one prospective, observational study found that treatment with oral THC/CBD (total daily doses ranging from THC 7 mg/CBD 14 mg to THC 13 mg/CBD 26 mg; average daily THC dose 9 mg after two months) was well tolerated and resulted in improvements in disruptive behaviors and rigidity.111

Two ongoing placebo-controlled RCTs are currently investigating the use of dronabinol (synthetic THC) (NCT02792257) and Avidekel oil (20:1 CBD:THC) (NCT03328676). To date, no trials have investigated the effects of CBD on agitation in patients with dementia. While it is premature to draw conclusions about the role of cannabinoids in treating BPSD, larger and longer trials are indicated to expand the evidence base.

CONCLUSIONS AND FUTURE DIRECTIONS

Despite the significant increase in cannabis use among older adults, there remains a paucity of evidence concerning its risks and benefits. Furthermore, few population-wide surveys of older adults have focused on attitudes, beliefs, and knowledge about cannabis or why older adults use cannabis, what products they use, and what their use patterns entail. At present, our understanding of the role of cannabis in brain health, injury risk, and drug interactions stems primarily from preclinical trials, adolescent and adult cohorts, and a limited number of smaller observational studies with older adults. It is unclear how well these data generalize to geriatric patients. In terms of using dronabinol, nabilone, pure THC, or 1:2 THC/CBD to treat BPSD, some studies have found promising results, but because of the inconsistency in the literature, it remains premature to draw reliable conclusions.

High-quality clinical trials investigating the safety profile of cannabis and the indications for use are sorely needed, especially as substance use continues to rise in aging Baby Boomers. Furthermore, evidence-based dosing strategies for older adult use of both medicinal and recreational cannabis would be helpful. It is also necessary to compare clinical grade cannabinoids (typically used in research studies) with commercially available products to understand whether findings in research studies can apply to commercial formulations of THC and CBD. However, there are various barriers to studying this population, not the least of which is that individuals aged 65 or older are often excluded from clinical research studies. Additionally, since cannabis is a Schedule I drug, federal regulations create barriers to conducting research, especially among older adults in nursing facilities, which are required to abide by federal, state, and local laws to receive funding.80 Despite these barriers, physician knowledge of trends in cannabis use and the potential implications of such use is necessary to appropriately manage medically and socially complex older patients. We propose the development of a new coordinated, multicenter collaboration to study cannabis use in a large cohort of individuals aged 65 or older, with due attention to variations in gender, social determinants of health, and comorbid conditions. Such a study would enable us to determine how cannabis use affects, and how it might be used to improve, older individuals’ quality of life.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

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Keywords:

cannabis; geriatric; marijuana; older adult; substance use

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