Advancing Cannabis Detection: Breath and Ocular Approaches

About This Grant

PROJECT SUMMARY The rise in cannabis use and its legalization in the US have increased concerns about impaired driving and public safety. Current approaches to detect recent cannabis use, such as biomarkers in blood or urine, are invasive and fail to reliably indicate recent use. Since peak drug impairment lasts for several hours after cannabis use, there is a need for objective, non-invasive, and portable detection methods within this timeframe. This study explores two promising approaches for detecting recent cannabis use: (1) breath sampling and (2) pupil dynamics. These methods are objective, non-invasive, portable. Furthermore, emerging evidence suggests these detect recent cannabis use during the window of acute impairment. Several devices using these approaches are nearly or already commercially available, yet independent validation of their uncertainty, reliability, and predictive validity is limited. This study will rigorously assess the performance of two breath sampling devices and two ocular devices. Using a within-subjects observational design, we will recruit 45 participants to compare device performance pre- and post-cannabis use. Over two years, we will address the following aims: (1) Test the repeatability of findings within and between detection methods. We will compare repeat measures of cannabinoids in breath, and pupil size and dynamics in response to light; (2) Determine the duration of detectable acute cannabis effects, using post-use assessments over 4.5 hours; (3) Evaluate the joint predictive validity of both detection methods. This study builds on preliminary data to refine detection protocols and inform industry standards. The overall goal of our program of research is to develop objective approaches to detect cannabis use and impairment to prevent injuries and promote public safety. This work builds on preliminary data, addresses a critical gap in the ability to detect cannabis-related impairment with real-time, non-invasive, and objective approaches. Validation of breath-sampling and pupil measurement approaches will provide actionable insights for law enforcement, public health, and transportation safety professionals in identifying and preventing cannabis impaired driving.