The expansion of retail recreational marijuana laws (RMLs) has increased access to cannabis among older adults, yet evidence on potential cognitive and mental health implications remains limited.  This study examines changes in cannabis use and self-reported cognitive and mental health outcomes among adults aged 45 and older following RML implementation, with particular attention to subpopulations aged 55+ and 65+.  Using Behavioral Risk Factor Surveillance System (BRFSS) data from 2015–2023, we implement a staggered treatment difference-in-differences design that exploits variation in the timing of state RML adoption.

We find that RML enactment is associated with a 1.3 percentage point increase in past-30-day marijuana use among adults aged 45 and older, with similar magnitudes across older age subgroups.  Despite increased reported use, we find no evidence of changes in self-reported confusion or memory loss.  However, RML adoption is associated with a 1.7 percentage point reduction in the probability of reporting any poor mental health day in the past 30 days.  These findings suggest that increased cannabis use following legalization among older adults is not accompanied by short-run increases in self-reported cognitive difficulties and may coincide with improvements in mental health indicators.

To address limitations of self-reported cognitive measures in BRFSS and to examine longer-term outcomes, we plan to extend this analysis using restricted-access Health and Retirement Study (HRS) data with detailed geographic identifiers.  This ongoing work will allow for a more comprehensive examination of the prevalence, progression, and severity of Alzheimer’s disease and related dementias (ADRD) in relation to cannabis exposure following legalization.  Together, these results provide early evidence on behavioral and mental health responses to cannabis policy among older adults and lay the groundwork for future causal analyses of cannabis use and ADRD risk.