CBD Reduced Behavioral Symptoms of Vascular Dementia in a Small Trial Without Affecting Cognition | Research

The takeaway

In a 4-week randomized trial of 30 patients with vascular dementia, CBD at 300 mg/day significantly reduced behavioral and psychiatric symptoms compared to placebo, without causing cognitive or functional decline.

Caregivers of dementia patients, geriatric psychiatrists, neurologists treating BPSD

Significant reduction in behavioral symptoms without cognitive decline

What the researchers found

CBD (300 mg/day for 4 weeks) significantly reduced scores on both the Neuropsychiatric Inventory (NPI, p=0.05) and the Brief Psychiatric Rating Scale (BPRS, p<0.05) compared to placebo. No significant differences were found in cognitive measures (MMSE) or functional outcomes (Katz Index, Lawton Scale). Adverse events were mild and similar between groups.

Why it matters

Behavioral and psychological symptoms of dementia (BPSD) are extremely distressing for patients and caregivers, and current treatments have limited efficacy and significant side effects. CBD showed meaningful symptom reduction without the cognitive dulling or falls risk associated with antipsychotics commonly used for BPSD.

The numbers in context

N=30 vascular dementia patients. CBD dose: 300 mg/day for 4 weeks. NPI improvement: F=3.61, p=0.05, partial eta squared=0.11. BPRS improvement: F=4.02, p<0.05, partial eta squared=0.13. No cognitive or functional changes. Mild, similar adverse events in both groups.

How the study worked

Randomized, double-blind, placebo-controlled trial of 30 patients with vascular dementia and clinically significant behavioral and psychological symptoms. Patients received CBD 300 mg/day or placebo for 4 weeks.

What this study cannot tell us

Very small sample (N=30) with only 4 weeks of treatment. Single dose tested. Cannot determine optimal dose or long-term safety. Vascular dementia is heterogeneous, and the sample may not represent all subtypes. Brazilian single-site study.

How to read the evidence

Preliminary evidence from a small but well-designed randomized, placebo-controlled trial.

When this study was published

2025 randomized controlled trial registered with the Brazilian Clinical Trials Registry.

The bigger picture

Vascular dementia is the second most common cause of dementia, and managing its behavioral symptoms is a major clinical challenge. This small but well-designed trial adds to growing interest in CBD for neurodegenerative conditions and suggests it may offer a safer alternative to antipsychotics for managing agitation and behavioral disturbances.

Questions still open

Would longer treatment duration produce cognitive benefits in addition to behavioral improvements? What is the optimal dose? Would CBD work similarly in Alzheimer's-type dementia? How does CBD compare head-to-head with antipsychotics for BPSD?

Common questions

Can CBD help with dementia behavior problems?

In this small trial, CBD at 300 mg/day significantly reduced behavioral and psychiatric symptoms of vascular dementia, including agitation and psychotic symptoms, without causing cognitive decline or significant side effects. Larger trials are needed to confirm these findings.

Is CBD safe for elderly dementia patients?

In this 4-week trial, CBD was well tolerated with only mild adverse events similar to placebo. Importantly, CBD did not worsen cognition or daily functioning, which distinguishes it from some currently used medications for dementia behavior problems.

Read the original research

Effects of cannabidiol on behavioral and psychological symptoms of vascular dementia: A randomized, double-blind, placebo-controlled clinical trial.

Journal of psychopharmacology (Oxford, England), 2698811251390974

View on PubMed ↗Publisher’s paper ↗

Citation

Pessoa, Rebeca Mendes P; Zuardi, Antonio Waldo; Martins-Filho, Rui Kleber V; Rodrigues, Guilherme Riccioppo; Hallak, Jaime E C; Crippa, José Alexandre S; Pontes-Neto, Octavio Marques; Chagas, Marcos Hortes N. (2025). Effects of cannabidiol on behavioral and psychological symptoms of vascular dementia: A randomized, double-blind, placebo-controlled clinical trial.. Journal of psychopharmacology (Oxford, England), 2698811251390974. https://doi.org/10.1177/02698811251390974