A systematic review of five trials found nabilone may reduce agitation in dementia patients, but THC showed no significant benefit for agitation and no studies tested cannabinoids for cognitive decline.
Families of dementia patients, geriatric psychiatrists, dementia researchers
Nabilone may help agitation but no cannabinoid has been shown to help dementia cognition
What the researchers found
Nabilone (1-2 mg/day) showed significant improvement in agitation in one trial. THC (1.5-4.5 mg/day) showed no significant differences from placebo for agitation in two trials. Dronabinol (5 mg/day) improved weight in one anorexia-focused trial. No studies examined cannabinoids for cognitive symptoms.
Why it matters
With dementia patients and families seeking new treatment options, this review provides a clear picture: there is a thin line of evidence for nabilone in agitation but essentially no support for cannabinoids improving cognition or disease progression.
The numbers in context
5 RCTs included; nabilone 1-2 mg/day improved agitation; THC 1.5-4.5 mg/day no benefit for agitation; dronabinol 5 mg/day improved weight; 0 studies on cognitive decline; evidence rated low to very low
How the study worked
Systematic review following PRISMA guidelines, searching Medline, Embase, Cochrane, and PsycINFO. Five randomized controlled trials met inclusion criteria.
What this study cannot tell us
Only five trials with low to very low quality evidence. Small sample sizes. Different cannabinoid preparations tested. No studies on cognitive outcomes. Short follow-up periods.
How to read the evidence
Systematic review with low to very low quality evidence from five small trials
When this study was published
Published in 2021. The evidence base for cannabinoids in dementia remains extremely limited.
The bigger picture
The distinction between nabilone (synthetic, possibly effective for agitation) and THC (natural, no clear benefit) suggests that different cannabinoids may have very different utility in dementia, and lumping them together is unhelpful.
Questions still open
- Why did nabilone succeed where THC failed for agitation? Should future trials focus exclusively on nabilone for behavioral symptoms? Would CBD, which has not been tested for dementia, show different results?
Common questions
Can cannabinoids help with dementia?
Should dementia patients try cannabis?
Read the original research
Effectiveness of Cannabinoids for Treatment of Dementia: A Systematic Review of Randomized Controlled Trials.
Clinical gerontologist, 44(1), 16-24
Citation
Charernboon, Thammanard; Lerthattasilp, Tiraya; Supasitthumrong, Thitipon. (2021). Effectiveness of Cannabinoids for Treatment of Dementia: A Systematic Review of Randomized Controlled Trials.. Clinical gerontologist, 44(1), 16-24. https://doi.org/10.1080/07317115.2020.1742832
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