Effect of long-term cannabidiol on learning and anxiety in a female Alzheimer's disease mouse model.

Cannabidiol is a promising potential therapeutic for neurodegenerative diseases, including Alzheimer's disease (AD). Our laboratory has shown that oral CBD treatment prevents cognitive impairment in a male genetic mouse model of AD, the hemizygous () mouse. However, as sex differences are evident in clinical populations and in AD mouse models, we tested the preventive potential of CBD therapy in female mice. In this study, 2.5-month-old female wildtype-like (WT) and mice were fed 20 mg/kg CBD or a vehicle gel pellets daily for 8 months and tested at 10.5 months in behavioural paradigms relevant to cognition (fear conditioning, FC; cheeseboard, CB; and novel object recognition test, NORT) and anxiety-like behaviours (elevated plus maze, EPM). In the CB, CBD reduced latencies to find a food reward in mice, compared to vehicle-treated controls, and this treatment effect was not evident in WT mice. In addition, CBD also increased speed early in the acquisition of the CB task in mice. In the EPM, CBD increased locomotion in mice but not in WT mice, with no effects of CBD on anxiety-like behaviour. CBD had limited effects on the expression of fear memory. These results indicate preventive CBD treatment can have a moderate spatial learning-enhancing effect in a female amyloid-β-based AD mouse model. This suggests CBD may have some preventive therapeutic potential in female familial AD patients.