Decoding Cannabis: Recent study on THC oil for Alzheimer’s agitation and sleep

For many of those affected, traditional treatment options simply do not bring effective symptom control, or the side effects are too severe to warrant sustained use. This has led to growing interest in a range of alternative treatment options, and medical cannabis treatment for Alzheimer’s disease is somewhat leading that charge right now, as researchers look for new approaches to ease the most distressing symptoms.

One recent THC Alzheimer’s study followed patients over 12 weeks while they received a cannabis oil rich in THC. The study tracked changes across mood, appetite, sleep and cognition, and many reported meaningful improvements. 

In this Decoding Cannabis entry, we break down what the study showed and see what it could mean for dementia care in the UK right now.

What does the 2023 THC oil study reveal about Alzheimer’s symptoms?

“Oral THC: CBD cannabis extract in main symptoms of Alzheimer's disease: agitation and weight loss”, the 2023 THC Alzheimer’s study in focus for today’s Decoding Cannabis blog was designed to assess the effects of a high-THC cannabis oil in older adults living with the condition. 

Thirty patients between 65 and 90 years old took part, each presenting with different symptom profiles, including disturbed sleep, disorientation, agitation and progressive cognitive decline. The oil contained 22% THC and 0.5% CBD, administered sublingually twice daily for 12 weeks.

Outcomes were tracked by the participant's family caregivers through standardised, validated questionnaires. These measured behavioural and psychological symptoms, agitation type and frequency, eating disturbances, cognitive change, along with one factor often skipped in these types of studies, but one that is extremely important to understand - caregiver distress.

The findings show measurable improvements across multiple areas, adding to the growing evidence for medical cannabis treatment for Alzheimer’s disease and reinforcing the potentially positive role that cannabinoid therapy may play in supporting people with dementia, and their caregivers. 

Did THC oil help control symptoms in Alzheimer’s patients? 

In a nutshell, yes. 

The study’s findings showed that for the majority of the participants, the medical cannabis oil positively impacted some of the condition’s most disruptive symptoms. 

THC for agitation and aggression in Alzheimer’s 

Physical and emotional agitation/aggression is an extremely distressing, albeit common, part of Alzheimer’s. It can manifest in many ways, with verbal outbursts, rising physical resistance (especially around care routines), and general restlessness to the point of heavy agitation being all too common. 

This study used the Cohen-Mansfield Agitation Inventory, which records how often behaviours like these occur. After 12 weeks of THC oil administration, scores dropped across all participants. 

• Verbal aggression became less frequent

• Care refusal became easier to manage

• Restless movement, such as pacing, verbalising, or aimless walking, reduced in intensity

Unfortunately, no exact score averages were published, but the direction and significance are clear - medical cannabis treatment for Alzheimer’s agitation and aggression is a clear treatment pathway worthy of further investigation. 

How THC oil affects appetite and weight in dementia patients

Appetite loss is a common concern in Alzheimer’s, particularly as the disease progresses into its later stages. Alongside the obvious challenges with food acceptance and weight stability, these shifts often trigger added aggression or emotional withdrawal. When food routines fall apart, everything else can feel that little bit harder to hold together.

21 of the 30 participants had a history of appetite loss or weight decline. After 12 weeks of THC oil treatment, 70% of those patients showed signs of improvement. 

Caregivers spoke about mealtimes being less strained. There were fewer refusals and a clearer willingness (even a want) to eat. Some families noticed clothes fitting a little better, or said they felt less anxious watching someone push food around on a plate without touching it.

Dementia-related eating disorders are rarely about hunger alone. In Alzheimer’s care, appetite often reflects how grounded and secure someone feels. If cannabis-based medicines can help support appetite stimulation and weight stability in these settings, the potential impact goes well beyond calories alone.

THC oil for sleep disturbance in Alzheimer’s patients

Again, as with appetite suppression, sleep disruptions are one of the most destabilising symptoms in overall Alzheimer’s care. We all know what it feels like to try to push through a normal workday after a broken night. 

Now imagine that happening every night, but instead of just having to open your computer or jump on the tube to work, you wake up not knowing where you are, what time it is, or why you keep waking up confused and severely under slept.

In the study, 19 out of 30 patients (just shy of 60%) showed measurable improvement in their sleep–wake rhythm. The researchers specifically noted a reduction in what’s known as “sundown syndrome”, which describes a pattern where people with Alzheimer’s become more agitated, anxious, or confused as daylight fades. 

While not fully resolved, these changes suggested that the THC oil may help soften the edges of this daily pattern, giving both patients and caregivers a more manageable night.

Cognitive effects of THC oil in dementia care

The cognitive outcomes in the study, while subtle, are definitely worthy of discussion. 

Alzheimer's is an incurable, a progressive condition. No cannabinoid therapy is currently classed as disease-modifying, and it is not a cure for Alzheimer’s disease. Even so, several patients appeared to regain small elements of clarity or responsiveness across the 12-week trial.

3 out of 30 patients improved their cognition scores, moving from the severe range (10–19) into the moderate range. 

Only 10% of patients improved their MMSE scores, which is not statistically significant in a formal sense. But for those individual cases, the improvements were supported by consistent behavioural observations recorded by caregivers.

What are the safety concerns and limitations of this research?

For the most part, the THC:CBD oil used in this study was well tolerated. No serious side effects were reported, and no patients discontinued treatment due to adverse events. For a study involving older dementia patients, that in itself is quite surprising.

The most common minor effects included dry mouth, drowsiness during the day, and occasional confusion at dose changes. These were typically short-lived and didn’t require stopping the medication.

Still, this was a small study. Thirty people, each with different needs and challenges. We don’t yet know how this would scale, or even if it would. That will take larger trials and longer timelines.

Researchers emphasised that treatment should be assessed on a case-by-case basis, especially in older or more medically complex patients. Medical cannabis is never a one-size-fits-all treatment option (no matter the health concern), and without larger trials, its safety profile in dementia care remains limited to studies like this.

What should families consider before trying cannabis care?

The first thing families need to understand is that medical cannabis is not a cure for Alzheimer’s disease. Any suggestion that it might be should raise concern. This study, and others like it, focus on symptom management, not disease reversal.

That said, the findings do point to real benefits for some patients. 

In cases where agitation, sleep disturbance, or appetite loss are making care more difficult, the study pointed to quite high rates of symptom control success. 

But it doesn’t work for everyone, and with such a small sample size, we simply cannot predict specific results for individual patients.

Can Alzheimer’s patients access THC-based treatment in the UK?

Medical cannabis is now legally available through Releaf medical cannabis clinic for all UK residents with certain medical conditions, including Alzheimer’s-related symptoms. 

Eligibility depends on specialist judgement, and for conditions with as many overlapping symptoms as Alzheimer’s, an extra level of clinical oversight and personalised assessment is often needed. 

Keep in mind that medical cannabis is not a ‘first-line’ treatment option here in the UK, meaning patients must have already tried at least two conventional options before they can be considered for a legal medical cannabis prescription

Rather than focusing on the condition alone, the doctors who make up Releaf’s world-class clinical team look at the symptoms that are proving hardest to manage. That might include agitation, sleep disruption, appetite loss, or increased anxiety. If conventional options have failed or caused further distress, a trial of cannabis-based treatment may be an option, but not always.

For families considering this route, the best place to start is with Releaf’s medical cannabis eligibility checker. It is free, takes less than 20 seconds, and gives you a clearer idea of your (or your loved ones) potential eligibility for legal UK medical cannabis treatment.