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Are There Systematic Reviews on Cannabis in Dementia? 

Posted
Updated
ByMy Patient Advice
Author: Julia Sutton, MSc | Reviewed by: Dr. Clarissa Morton, PharmD

As interest in medical cannabis continues to grow, researchers have examined whether cannabinoids could help manage dementia symptoms such as agitation, anxiety, or sleep disturbance. Over the past few years, several systematic reviews and meta-analyses have summarised available evidence, and all reach a similar conclusion: the evidence remains weak and inconsistent, and cannabis is not recommended for dementia treatment under current NHS or NICE guidance (NICE NG97; NICE NG144). 

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What Systematic Reviews Have Found 

Systematic reviews are valuable because they combine findings from multiple studies to assess the overall quality and consistency of evidence. Between 2023 and 2025, researchers reviewed all clinical trials of cannabis-based medical products in people with dementia. 

2023–2024 Meta-Analyses 

A major 2024 meta-analysis published on PubMed assessed cannabinoids such as THC, CBD, dronabinol, and nabilone for behavioural and psychological symptoms of dementia (BPSD). It found no significant improvement in global agitation scores, cognitive function, or overall quality of life compared with placebo (Systematic Review, 2024). 

The analysis noted that most included studies were small (fewer than 50 participants), short-term (under 12 weeks), and often lacked consistent measures of symptom change. Mild improvements were sometimes reported in secondary outcomes like sleep or irritability, but these were not statistically meaningful. 

Individual Trial Summaries 

A 2023 double-blind crossover trial of cannabinoids in dementia found that while agitation scores improved slightly, cognitive performance and overall function did not change. Adverse effects such as drowsiness, dizziness, and confusion were reported in a minority of participants (PubMed Trial, 2023). 

Similarly, a 2024 Swiss feasibility study testing oral THC/CBD oil in people with severe dementia found the treatment to be well tolerated but without significant clinical benefit (Swiss Study). Researchers concluded that larger, longer studies are needed before cannabis could be considered for therapeutic use. 

What The Reviews Agree On 

Across all systematic reviews and surveillance reports, the consensus is clear: 

  • Evidence is inconclusive. Minor improvements in agitation or sleep may occur, but these effects are inconsistent. 
  • No cognitive benefits have been shown. Cannabis-based products do not improve memory, attention, or daily function. 
  • Safety data are limited. Older adults with dementia may be more prone to sedation, confusion, or falls. 
  • Quality of evidence is low. Many studies have small sample sizes, short durations, and differing formulations of cannabinoids. 

What UK Guidelines Say 

The NHS and NICE both confirm that cannabis-based medical products are not licensed or recommended for dementia or its behavioural symptoms. NICE surveillance updates in 2023 reaffirmed that there is no robust evidence to justify clinical use, and dementia is not among the conditions for which cannabis can legally be prescribed (NHS Guidance; NICE 2023 Surveillance Review). 

Cannabis-based medicines can currently only be prescribed by specialist doctors for certain conditions such as severe epilepsy, chemotherapy-induced nausea, and spasticity in multiple sclerosis, but not for dementia symptoms or cognitive decline. 

The Alzheimer’s Society UK supports this position, stating that cannabis and CBD products are not proven to treat, slow, or prevent dementia. It highlights that claims of benefit are often anecdotal and unsupported by clinical trials (Alzheimer’s Society). 

Global Health Perspectives 

The World Health Organization (WHO) echoes this caution, noting that while cannabinoids may have therapeutic potential in some neurological disorders, no conclusive evidence supports their use for dementia-related symptoms or cognitive function. WHO’s review on cannabis and cannabinoids emphasises the need for longer-term, well-controlled studies before considering medical application in dementia (WHO: Cannabis and Cannabinoids). 

The Clinical Bottom Line 

  • Multiple systematic reviews (2023–2025) show no consistent evidence that cannabis improves dementia symptoms. 
  • Minor improvements in agitation or sleep may occur, but cognitive benefits are unproven. 
  • Adverse effects such as drowsiness, confusion, and dizziness remain concerns for older adults. 
  • NICE, NHS, WHO, and Alzheimer’s Society do not recommend cannabis-based products for dementia outside research trials. 
  • Further large-scale, randomised studies are required to determine safety, efficacy, and long-term outcomes. 

Educational Context: AlleviMed 

Educational platforms such as AlleviMed provide information about how medical cannabis eligibility is assessed in the UK. They explain that cannabis-based medicines are only prescribed within narrow legal frameworks, for specific licensed conditions such as multiple sclerosis or severe epilepsy, not for dementia. AlleviMed’s materials help patients and carers understand the difference between research participation and approved clinical use, promoting informed, evidence-based decision-making. 

Takeaway 

Although systematic reviews continue to explore the role of cannabis in dementia, current findings remain inconclusive and low-quality. NICE, NHS, WHO, and Alzheimer’s Society UK all agree that cannabis-based medical products should not be used to treat dementia outside formal research. The safest, most effective care for people with dementia still relies on evidence-based medical support, behavioural strategies, and early specialist involvement, not unproven cannabis therapies. 

Julia Sutton, MSc
Author

Julia Sutton is a clinical psychologist with a Master’s in Clinical Psychology and experience providing psychological assessment and therapy to adolescents and adults. Skilled in CBT, client-centered therapy, and evidence-based interventions, she has worked with conditions including depression, anxiety, bipolar disorder, and conversion disorder. She also has experience in child psychology, conducting psycho-educational evaluations and developing tailored treatment plans to improve learning and well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the author's privacy. 

Dr. Clarissa Morton, PharmD
Reviewer

Dr. Clarissa Morton is a licensed pharmacist with a Doctor of Pharmacy degree and experience across hospital, community, and industrial pharmacy. She has worked in emergency, outpatient, and inpatient pharmacy settings, providing patient counseling, dispensing medications, and ensuring regulatory compliance. Alongside her pharmacy expertise, she has worked as a Support Plan & Risk Assessment (SPRA) officer and in medical coding, applying knowledge of medical terminology, EMIS, and SystmOne software to deliver accurate, compliant healthcare documentation. Her skills span medication safety, regulatory standards, healthcare data management, and statistical reporting.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the reviewers's privacy. 

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