Hollis Karoly, PhD and Patti Davies, PhD
Assistant Professor, Department of Psychology (HK), and Professor, Department of Occupational Therapy (PD), Colorado State University
Alcohol and cannabis are commonly used at the same time and are both known to impair cognitive and psychomotor functions relevant for driving. Following legalization of recreational cannabis in Colorado, DUIs involving cannabis (including cannabis in combination with alcohol) have increased. Currently, there are no validated roadside tests of cannabis-intoxication or co-intoxication, and considerable further research in this area is needed. This project aims to inform the eventual development of roadside tests for cannabis use and co-use, informed by electroencephalography (EEG). Specifically, we will assess neurocognitive function in 3 groups of human participants who are randomly assigned to consume alcohol, cannabis or both alcohol and cannabis during an experimental session in our federally-compliant mobile laboratory. The neurocognitive measures derived from EEG separate the phases of cognitive processing including attention, discrimination, decision making, error detection and adapting behavior to correct errors. The goal of this study is to use EEG to differentiate alcohol and cannabis co-intoxication from single-substance intoxication and identify which of the aforementioned neurocognitive components are most strongly associated with alcohol, cannabis or co-use. We will also compare relative predictive strength of EEG measures and traditional roadside intoxication measures (balance, blood-THC levels, blood-alcohol concentration) to shed light on potential combinations of measures that may be able to accurately identify single-substance intoxication and co-use intoxication.