Medical cannabis and cognitive performance in middle to old adults treated for chronic pain

Introduction and aims: Cannabis exposure is becoming more common in older age but little is known about how it is associated with brain health in this population. This study assesses the relationship between long-term medical cannabis (MC) use and cognitive function in a sample of middle-aged and old chronic pain patients.

Design and methods: A cross-sectional study was conducted among chronic pain patients aged 50+ years who had MC licenses (n = 63) and a comparison group who did not have MC licenses (n = 62). CogState computerised brief battery was used to assess cognitive performance of psychomotor reaction, attention, working memory and new learning. Regression models and Bayesian t-tests examined differences in cognitive performance in the two groups. Furthermore, the associations between MC use patterns (dosage, cannabinoid concentrations, length and frequency of use and hours since last use) with cognition were assessed among MC licensed patients.

Results: Mean age was 63 ± 6 and 60 ± 5 years in the non-exposed and MC patients, respectively. Groups did not significantly differ in terms of cognitive performance measures. Furthermore, none of the MC use patterns were associated with cognitive performance.

Discussion and conclusions: These results suggest that use of whole plant MC does not have a widespread impact on cognition in older chronic pain patients. Considering the increasing use of MC in older populations, this study could be a first step towards a better risk-benefit assessment of MC treatment in this population. Future studies are urgently needed to further clarify the implications of late-life cannabis use for brain health.

Keywords: chronic pain; cognitive decline; medical cannabis; older population.