Despite preliminary evidence of unique acute cognitive and psychopharmacological changes attributable to combined alcohol and cannabis use, few studies have investigated more chronic effects of same-day co-use, particularly during neurodevelopmentally sensitive periods. Therefore, relationships between past-month binge alcohol and cannabis co-use and cognitive functioning were examined in adolescents and young adults.
Data from the Imaging Data in Emerging Adults with Addiction (IDEAA) Consortium were used to assess cognitive functioning in 232 emerging adults, aged 15–26 years old, with a large range of substance use who were abstinent for at least 3 weeks. Multiple regressions assessed cognitive functioning by past-month binge episodes, cannabis use episodes, and same-day co-use, controlling for covariates (e.g., study site, sex, age). After correcting for multiple comparisons, more past-month co-use episodes were related to decreased Ruff 2&7 selective attention accuracy. Sex significantly covaried with California Verbal Learning Test–Second Edition initial learning.
The authors comment that although few significant relationships were found and effect sizes were modest, the persistence of an effect on attention despite a period of sustained abstinence highlights the need to carefully investigate patterns of substance use and potential independent and interactive effects on the developing brain.
Source: Wade NE, Bagot KS, Tapert SF, Gruber SA, Filbey FM, Lisdahl KM. Cognitive Functioning Related to Binge Alcohol and Cannabis Co-Use in Abstinent Adolescents and Young Adults. J Stud Alcohol Drugs. 2020;81(4):479-483.