Objective: Neuropsychiatric symptoms (NPS) of dementia represent a large driver of health care costs, caregiver burden, and institutionalization of people with dementia. Management options are limited, and antipsychotics are often used, although they carry a significant side effect profile. One novel option is tetrahydrocannabinol (THC); however, in the US, to obtain THC for patients with dementia, caregivers have to go to a commercial dispensary. We evaluated the effectiveness of dispensary-obtained THC for patients with dementia and NPS.

Methods: Two independent reviewers reviewed charts of patients with diagnosed dementia (N = 50) seen in geriatric psychiatry between 2017 and 2021 for whom dispensary-obtained THC was recommended. The primary outcome was effectiveness in treating NPS; secondary outcomes were the proportion of caregivers who obtained and administered THC (uptake), post-THC antipsychotic use, and adverse reactions leading to treatment discontinuation.

Results: Caregiver uptake of dispensary-obtained THC was high (38/50, 76%). The majority of patients (30/38, 79%) who took THC had an improvement in NPS according to their caregivers. THC was recommended most often for the NPS of agitation, aggression, irritability, lability, anxiety, and insomnia. Among the 20 patients who were taking antipsychotics at baseline and took THC, over half (12/20, 60%) were able to decrease or discontinue the antipsychotic. Adverse reactions to THC included dizziness, worsening of agitation, and worsening of paranoia; two caregivers of patients who took THC reported adverse reactions that led to treatment discontinuation.

Conclusions: Our results suggest that dispensary-obtained THC can be effective in managing a subset of NPS in patients with dementia and may decrease the requirement for antipsychotics.