Effects of acute cannabis inhalation on reaction time, decision-making, and memory using a tablet-based application

Daily cannabis users show less impairment in reaction time and short-term memory after smoking than occasional users, suggesting they develop tolerance to some acute effects. In a tablet-based test battery, occasional users slowed down and remembered fewer shapes after smoking cannabis with 15–30% THC, while daily users did not differ from non-users on those measures. On a gap-acceptance decision task, daily users took longer after smoking but maintained accuracy, possibly prioritizing correctness over speed. The findings indicate that tolerance to certain psychomotor and cognitive effects can develop with daily use, and that tablet-based assessments may help detect recent cannabis impairment.

Study at a glance

Abstract

Background Acute cannabis use has been demonstrated to slow reaction time and affect decision-making and short-term memory. These effects may have utility in identifying impairment associated with recent use. However, these effects have not been widely investigated among individuals with a pattern of daily use, who may have acquired tolerance. The purpose of this study was to examine the impact of tolerance to cannabis on the acute effects as measured by reaction time, decision-making (gap acceptance), and short-term memory. Methods Participants (ages 25–45) completed a tablet-based (iPad) test battery before and approximately 60 min after smoking cannabis flower. The change in performance from before to after cannabis use was compared across three groups of cannabis users: (1) occasional use ( n = 23); (2) daily use ( n = 31); or (3) no current use ( n = 32). Participants in the occasional and daily use group self-administered ad libitum , by smoking or vaping, self-supplied cannabis flower with a high concentration of total THC (15–30%). Results The occasional use group exhibited decrements in reaction time (slowed) and short-term memory (replicated fewer shapes) from before to after cannabis use, as compared to the no-use group. In the gap acceptance task, daily use participants took more time to complete the task post-smoking cannabis as compared to those with no use or occasional use; however, the level of accuracy did not significantly change. Conclusions The findings are consistent with acquired tolerance to certain acute psychomotor effects with daily cannabis use. The finding from the gap acceptance task which showed a decline in speed but not accuracy may indicate a prioritization of accuracy over response time. Cognitive and psychomotor assessments may have utility for identifying impairment associated with recent cannabis use.