CALM-IT is a Randomized, double-blind, placebo-controlled cross-over clinical trial. Safety and efficacy of cannabidiol (CBD) capsules assessed for managing agitation in patients with AD and to identify novel biomarkers of agitation severity and treatment response.

This study will look at whether CBD is an effective treatment for agitation in Alzheimer's disease (AD). This naturally derived CBD is highly pure (99%) and made by a manufacturer who meets Health Canada guidelines Cannabis products are legal for purchase in Canada.

Agitation is common in AD and is known to correlate with physical health problems such as falls and weight loss, AD progression, and caregiver burden. Current treatments for agitation in AD are not beneficial for everyone and there are concerns regarding their safety. Treating agitation is important in improving the quality of life of AD patients and their families and there is a need to identify safer and more effective treatments for agitation in AD.

The structure of this trial is called a "cross-over study". Participants will be randomized to receive either CBD or placebo during the first of two treatment phases. They will then cross-over to the opposite treatment during the second treatment phase. Participants will be on the study treatment for a total of 19 weeks and then will be followed for 4 more weeks after finishing the study treatment. There will be 12 study visits approximately every 2 weeks and 8 telephone visits every week during the study.

In addition to looking at the effectiveness of CBD in treating agitation, the researchers will also look at whether it is beneficial for other relevant outcomes for patients with AD including overall neuropsychiatric symptoms, caregiver distress, cognition, nutritional status, and pain.

Inclusion Criteria:

1. Males or females ≥55 years of age; female must be post-menopausal or must agree to comply with contraception requirements. Males should also abide by contraceptive requirements when the partner is a woman of childbearing potential. Acceptable methods of contraception include: combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation, which may be oral, intravaginal, or transdermal; progestogen-only hormonal contraception associated with inhibition of ovulation, which may be oral, injectable, or implantable; intrauterine device or intrauterine hormone-releasing system; vasectomy of a female subject's male partner (with medical assessment and confirmation of vasectomy surgical success); bilateral tubal occlusion
2. Diagnostic and Statistical Manual of Mental Disorders-5 (DSM 5) criteria for Major Neurocognitive Disorder due to possible AD. Patients with Major Neurocognitive Disorder due to multiple etiologies (AD and vascular) will be included
3. sMMSE ≤24
4. Presence of clinically significant agitation based on the IPA definition at both screening and baseline
5. If treated with cognitive-enhancing medications (cholinesterase inhibitors and/or memantine), dosage must be stable for at least 3 months prior to study randomization
6. Availability of a primary caregiver to accompany the participant to study visits and to participate in the study. The primary caregiver must be sufficiently proficient in English to complete the required study assessments, as per investigator judgement and should spend at least 10 hours a week with the participant
7. Willing and able to provide informed consent and/or have a Substitute Decision Maker (SDM) provide informed consent on behalf of the participant

Exclusion Criteria:

1. Change in psychotropic medications less than the duration of 5 half-lives of the medication in question prior to screening (e.g., concomitant antidepressants or atypical antipsychotics) and any changes during study participation
2. Contraindications to CBs, e.g. allergies to cannabis and cannabis products, potential clinically important drug-drug interactions (e.g. strong CYP3A4 inducers/inhibitors, anticonvulsants)
3. Vascular disease, clinically important cerebrovascular disease or current uncontrolled cardiovascular disease (e.g. uncontrolled hypertension, ischemic heart disease, arrhythmia and severe heart failure, cardiovascular accident in the 3 months prior to Screening (V1)), as per investigator assessment
4. Clinically significant liver disease, as reflected by serum alanine aminotransferase or aspartate aminotransferase > 2 x upper limit of normal (ULN), or total bilirubin > 1.5 x ULN; The Investigator may decide to repeat the assessment to confirm criterion prior to screen failing the participant
5. Clinically significant impaired renal function at screening, as per investigator assessment
6. Currently meeting DSM 5 criteria for Major Depressive Episode Presence, or current substance dependence (excluding caffeine and nicotine) or history of other major psychiatric disorders or neurological conditions (e.g. psychotic disorders, schizophrenia, stroke, epilepsy)
7. Substance-Related Disorders (excluding caffeine and nicotine)
8. Clinically significant delusions and/or hallucinations (e.g. NPI-NH delusion/hallucinations subscore ≥4 or judgement of QI)
9. Reported use of marijuana or cannabinoid-based medications, products or supplements (botanical or synthetic) within 1 week prior to randomization
10. Systolic blood pressure (SBP) < 90 mmHg or > 150 mmHg or diastolic blood pressure (DBP) < 50mmHg or > 105 mmHg at screening or baseline (prior to randomization) or a postural drop in SBP ≥ 20 mmHg or DBP ≥ 10 mmHg at screening

This is a double-blind study. Participants, Subsequent decision maker and investigator will be blinded to the treatment arm. Unblinding will not be allowed unless there are exceptional clinical circumstances that justify it