Cannabis & dementia: what the literature actually rests on
A co-citation analysis of the field's key papers — built from the citation graph, not the headlines.
stoagen · author: Denson Smith · 2026-06-30
How this was made. Nine key cannabis-and-dementia papers (reviews, trials, and
preclinical landmarks) were pulled, and their reference lists were read from OpenAlex's citation
graph. The papers cited in common reveal the field's shared foundation; the references the
recent papers add (that the old reviews lack) reveal what's new. The OA PDFs were fetched with
compile-papers (3 of 9 open directly; 6 OA-but-bot-blocked). The co-citation structure is reliable
metadata; the 2024–26 "current frontier" figures (below) came from grounded web search and are flagged as
not-yet-independently-verified.
The clinical lane matured from open-label case work to randomized trials; the mechanism lane — the "disease-modifying" hope — has stayed in animals and cells the entire time.
1 · The shared foundation — three pillars
Across the nine key papers, 21 works are cited by three or more of them. Sorted, they fall into three
layers — effectively the skeleton of the field.
Pillar 1 · receptor bedrock
The ~5,000-citation papers everyone stands on — you can't discuss cannabis-and-brain without them.
Splitting the set into old reviews (2010–2015) and recent (2020–2024), the references the recent papers
add — absent from the old ones, and postdating them — cluster into three kinds of "new."
1
Anecdote became RCTs. The biggest change. The recent reviews rest on a new layer of randomized trials for agitation — Herrmann 2019 (nabilone RCT, cited by 3/6 recent), the two van den Elsen 2015 THC RCTs (Neurology, J Am Geriatr Psychiatry), Shelef 2016, and the THC dosing/safety work (Ahmed 2015). The 2024 Johns Hopkins dronabinol trial is the next link in a clean lineage: Volicer '97 → van den Elsen '15 → Herrmann '19 → Rosenberg '24.
2
A mechanism beyond CB1/CB2: PPAR.O'Sullivan 2016 — "PPAR activation by cannabinoids" — is a genuinely new axis (cannabinoids acting via PPARγ, not just the classic receptors). Notably the same PPARγ pathway the scleroderma cannabinoid drug EHP-101 targeted — the cannabinoid-PPAR mechanism recurs across cases. Plus Cassano 2017 (CB2 in neurodegeneration) and Zou 2018 (refreshed endocannabinoid-system review).
3
Imported rigor — and the harm side. The recent reviews cite Whiting 2015 (the JAMA gold-standard evidence review, 2,108 cit) and Marconi 2016 (cannabis → psychosis-risk meta-analysis). The old reviews were almost purely "promising"; the new ones weigh harms — the balanced posture the 2023 BMJ umbrella review embodies.
3 · The synthesis
The field grew up, but unevenly. The genuine advance is concentrated in the clinical pillar:
the human evidence matured from anecdote to randomized trials, and the stance matured from enthusiasm to
honest risk/benefit weighing. The neuroprotection / disease-modification story — the exciting part —
is still riding on the same mouse and dish work from 1998–2007, with only incremental additions. In
short: the field is finally testing in humans what it hypothesized in mice two decades ago, and the
only thing with real clinical support is symptom control (agitation), not slowing the disease.
4 · The current frontier (2024–2026)
Verification flag: the figures in this section came from grounded web search,
not the citation graph, and have not been independently checked against the source papers. Treat as
leads, not established facts.
Risk is a marker, not a proven cause. A 2025 JAMA Neurology cohort (Myran, ~6M adults) tied cannabis-related acute care to a ~72% higher 5-year dementia risk — but a Mendelian-randomization study (genetic causal inference) found no causal link for moderate/lifetime use. Heavy/disordered use flags risk via shared factors more than it causes dementia.
Treatment signal is firming up — for agitation. A 2024 Johns Hopkins/Tufts dronabinol trial reported ~30% agitation reduction vs placebo, well tolerated — meaningful because the alternative (antipsychotics) carries black-box stroke/death warnings.
Every citation-graph paper has a working DOI link. The §4 "current frontier" items came from grounded web search and are deliberately not in this list.
Matsuda LA, et al. Structure of a cannabinoid receptor and functional expression of the cloned cDNA. Nature 1990. doi:10.1038/346561a0
Munro S, et al. Molecular characterization of a peripheral receptor for cannabinoids. Nature 1993. doi:10.1038/365061a0
Pertwee RG. The diverse CB1 and CB2 receptor pharmacology of three plant cannabinoids: THC, CBD and THCV. Br J Pharmacol 2007. doi:10.1038/sj.bjp.0707442
Hampson AJ, et al. Cannabidiol and Δ9-tetrahydrocannabinol are neuroprotective antioxidants. PNAS 1998. doi:10.1073/pnas.95.14.8268
Benito C, et al. Cannabinoid CB2 receptors and FAAH are selectively overexpressed in Alzheimer's disease brains. J Neurosci 2003. doi:10.1523/jneurosci.23-35-11136.2003
Esposito G, et al. Cannabidiol in vivo blunts β-amyloid induced neuroinflammation. Br J Pharmacol 2007. doi:10.1038/sj.bjp.0707337
Cheng D, et al. Long-term cannabidiol treatment prevents social recognition memory deficits in AD transgenic mice. J Alzheimers Dis 2014. doi:10.3233/jad-140921
Eubanks LM, et al. A molecular link between the active component of marijuana and Alzheimer's disease pathology. Mol Pharm 2006. doi:10.1021/mp060066m
Walther S, et al. Δ9-tetrahydrocannabinol for nighttime agitation in severe dementia. Psychopharmacology 2006. doi:10.1007/s00213-006-0343-1
van den Elsen GAH, et al. Tetrahydrocannabinol for neuropsychiatric symptoms in dementia: an RCT. Neurology 2015. doi:10.1212/wnl.0000000000001675
van den Elsen GAH, et al. Tetrahydrocannabinol in behavioral disturbances in dementia: a crossover RCT. Am J Geriatr Psychiatry 2015. doi:10.1016/j.jagp.2015.07.011
Shelef A, et al. Safety and efficacy of medical cannabis oil for behavioral and psychological symptoms of dementia. J Alzheimers Dis 2016. doi:10.3233/jad-150915
Bahji A, et al. Cannabinoids for the neuropsychiatric symptoms of dementia: a systematic review. Can J Psychiatry 2019. doi:10.1177/0706743719892717
Herrmann N, et al. Randomized placebo-controlled trial of nabilone for agitation in Alzheimer's disease. Am J Geriatr Psychiatry 2019. doi:10.1016/j.jagp.2019.05.002
Ahmed AIA, et al. Safety, pharmacodynamics, and pharmacokinetics of multiple oral doses of Δ9-THC in dementia. Psychopharmacology 2015. doi:10.1007/s00213-015-3889-y
O'Sullivan SE. An update on PPAR activation by cannabinoids. Br J Pharmacol 2016. doi:10.1111/bph.13497
Cassano T, et al. Cannabinoid receptor 2 signaling in neurodegenerative disorders. Front Neurosci 2017. doi:10.3389/fnins.2017.00030
Zou S, Kumar U. Cannabinoid receptors and the endocannabinoid system: signaling and function in the CNS. Int J Mol Sci 2018. doi:10.3390/ijms19030833
Whiting PF, et al. Cannabinoids for medical use: a systematic review and meta-analysis. JAMA 2015. doi:10.1001/jama.2015.6358
Marconi A, et al. Meta-analysis of the association between the level of cannabis use and risk of psychosis. Schizophr Bull 2016. doi:10.1093/schbul/sbw003
Method: co-citation + reference-differential analysis over 9 key papers via the OpenAlex reference graph;
OA PDFs via compile-papers; current-state scan via grounded web search. Citation counts and DOIs are from
OpenAlex. stoagen · Denson Smith. Bio/literature skills built on lamm-mit's scienceclaw (Apache-2.0).