JMIR Publications

ABSTRACT

Background:

Marijuana initiation at age 50 and older has increased exponentially due to changing cultural norms and legalization of medical marijuana. Though marijuana use has increased among all age groups in the U.S., middle-aged and older adults show the greatest increase – growing 300% in the last 10 years. Currently evidence shows that acute marijuana use impairs psychomotor functions in real-world tasks such as driving. However, we do not know how habitual use of medical marijuana affects psychomotor functioning – particularly among older adults.

Objective:

The aim of this study was to pilot a protocol to examine psychomotor function and medical marijuana using a driving performance task among adults 50 and older.

Methods:

Participants were adults aged 50 years and older, newly registered with the State of Florida to obtain medical marijuana, or age-, race-, and sex-matched control non-marijuana users. Driving performance was measured using an immersive, high-fidelity driving simulator.

Results:

There was no significant difference between the intervention and control groups for any driving variables at T1. At T2, reaction time to divided attention situation 3 (DA3) was significantly shorter in the intervention group (N = 14, M = 2.57, SD = 1.63) than the control group (N = 7, M = 5.79, SD = 4.32), t(19) = -2.50, p = .02, g = -1.11, 95% CI [-2.04, -0.16]; the number of times participants reacted to divided attention events was significantly greater in the intervention group (N = 12, M = 3.42, SD = .67) than in the control group (N = 7, M = 2.57, SD = .98), t(17) = 2.25, p = .04, g = 1.02, 95% CI [0.06, 1.96].

Conclusions:

Our study suggests a more nuanced story of the relationship between medical marijuana use and psychomotor function with medical marijuana users demonstrating better performance. Additional studies are required to clarify and replicate these results. Clinical Trial: ClinicalTrials.gov NCT04629716