Does Cannabis Reduce Hallucinations or Psychosis in Dementia?

PostedMarch 12, 2026

UpdatedMarch 12, 2026

ByMy Patient Advice

Author: Julia Sutton, MSc | Reviewed by: Dr. Clarissa Morton, PharmD

Hallucinations and psychosis are distressing symptoms that can occur in some forms of dementia, particularly Lewy body dementia and Alzheimer’s disease. These symptoms often involve seeing or hearing things that are not present and can lead to confusion, agitation, and fear. Traditional treatments, such as antipsychotics, can have serious side effects in older adults. Researchers are exploring whether cannabis-based compounds like THC and CBD might offer a safer alternative. While early studies suggest some calming potential, cannabis is not currently recommended for hallucinations or psychosis in dementia.

Understanding Hallucinations and Psychosis in Dementia

Hallucinations in dementia arise from chemical and structural changes in the brain, particularly in regions that process sensory information. Psychosis can also stem from dopamine imbalances, making people more prone to delusions or paranoia. According to NHS guidance on dementia, non-drug strategies should always be the first approach, such as reassurance, consistent routines, and managing triggers like sensory overload or infection.

Can Cannabis Help?

Cannabis interacts with the brain’s endocannabinoid system, which helps regulate neurotransmitters such as dopamine, glutamate, and GABA, all linked to psychotic symptoms.

CBD has been studied for its antipsychotic properties, potentially reducing hallucinations and paranoia by modulating CB1 and serotonin (5-HT1A) receptors.

THC, however, may have the opposite effect. At higher doses, THC can increase dopamine activity and trigger or worsen hallucinations, especially in people vulnerable to psychosis.

A 2023 review in Frontiers in Psychiatry (PubMed 38447959) found that CBD may help reduce psychotic symptoms in neurodegenerative conditions, while THC should be used with caution. A 2024 systematic review (PMC9557769) concluded that low-dose CBD might have neuroprotective and antipsychotic potential, though evidence in dementia remains limited.

What Do NICE And NHS Say?

According to NICE guidance NG97 and NICE NG144, cannabis-based medicinal products are not recommended for psychosis, hallucinations, or other behavioural symptoms in dementia. The Alzheimer’s Society UK advises that current studies are too small to confirm safety or effectiveness and that cannabis should only be explored under specialist supervision.

Clinical Bottom Line

CBD shows early evidence of reducing psychotic symptoms through neurochemical modulation.

THC may worsen hallucinations and anxiety, particularly at higher doses.

Evidence remains weak, with limited data specific to dementia-related psychosis.

NICE and NHS recommend non-drug strategies and clinical monitoring over cannabis-based treatments.

Educational Context: AlleviMed

AlleviMed provides educational resources about medical cannabis regulation in the UK. It explains how products are prescribed under MHRA and Home Office frameworks and clarifies that cannabis is not licensed for hallucinations or psychosis in dementia.

Takeaway

While CBD may have potential antipsychotic effects, there is no strong evidence that cannabis reduces hallucinations or psychosis in dementia. In fact, THC may worsen these symptoms. According to NICE and NHS guidance, non-drug interventions and specialist care remain the safest and most effective strategies for managing psychosis in dementia.

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.