THC-CBD formulation cut agitation in late-stage dementia trial

In a first-of-its-kind clinical trial, a medical formulation combining purified THC and CBD significantly reduced agitation in people with late-stage dementia compared with placebo, U.S. researchers reported July 14 at the Alzheimer's Association International Conference in London. The LiBBY trial — Life's end Benefits of cannaBidiol and tetrahYdrocannabinol — enrolled 120 hospice-eligible participants with Alzheimer's disease or other types of dementia who were experiencing agitation, with a mean age of 80. Ten medical centers nationwide conducted the study visits at participants' homes or places of residence. Participants were randomly assigned to receive either the oral, rapid-acting digestible oil suspension or a placebo, and neither the participants, their caregivers, nor the clinicians knew who received the active treatment.

Caregivers gave the medication and rated agitation on the Cohen-Mansfield Agitation Inventory, a 29-factor survey scored on a seven-point scale from "never" to "several times per hour." At two weeks, the primary outcome because of the drug's fast-acting nature, mean agitation scores fell 6.27 points more in the THC/CBD group than in the placebo group, and at 12 weeks there was a significant, sustained reduction. On a key secondary measure, the Clinical Global Impression of Change in Behavior, the THC/CBD group was much less agitated at two weeks, 83.9% versus 30.5% on placebo, and at 12 weeks, 87.2% versus 23.6%. Adverse events such as infections and gastrointestinal disorders occurred at comparable rates, 46.7% versus 42.4%, and were expected occurrences in this patient population.

Co-lead investigator Brigid Reynolds of Georgetown University said agitation causes restlessness, aggression and emotional distress that can profoundly affect patients and their caregivers, and that current treatment options are limited and often carry significant side effects. According to Georgetown, medications such as morphine, Valium and Haldol have had limited effectiveness against dementia-related agitation and can cause undesirable side effects. Co-lead Jacobo Mintzer of the Medical University of South Carolina said close to 90% of patients responding positively is a level rarely seen in dementia trials. Participants who completed the double-blind portion through week 12 were offered an additional 12 weeks of active treatment without chance of placebo.