Alcohol and Cannabis Use Account for Mental Health Differences across Hallucinogen Risk Levels Among College Students

Background/Purpose: Hallucinogen (e.g., MDMA, LSD, psilocybin) use among young adults has reached historically high, with 9.7% reporting past-year use in 2024, yet most research examines hallucinogen use as binary (i.e. use vs no-use) without examining risk-level differences. Prior studies report associations between hallucinogen use and psychological distress, but few account for concurrent alcohol and cannabis use, making it difficult to determine whether hallucinogen risk contributes independently. Examining positive functioning (e.g., flourishing, resilience), service engagement, and intimate partner violence (IPV) alongside distress offers a fuller picture of risk and protective factors of hallucinogen use. This study used World Health Organization Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) to examine mental health outcomes, service utilization, and IPV across three hallucinogen risk levels, and tested whether these differences persisted after adjusting for concurrent substance use.

Methods: This cross-sectional secondary analysis used 2023-2024 ACHA-NCHA-III data, a national college studentsurvey. The analytic sample included 3,992 students with hallucinogen involvement on the ASSIST and complete data on all study variables. Students were classified into low- (0-3), moderate- (4-26), and high-risk (27-39) groups based on hallucinogen involvement scores. Outcomes included psychological distress, loneliness, suicide risk, flourishing, resilience, past-year mental health service use, and IPV. ANOVAs compared continuous outcomes across risk groups.ANCOVAs adjusted for alcohol and cannabis ASSIST scores, age, and sex. Hierarchical logistic regressions predicted service use and IPV, controlling for demographics, substance use, and hallucinogen risk. All analyses were conducted in SPSS v29.

Results: Of the 3,992 participants (M_age=24.17, SD=6.82; 50.5% female; 72.1% non-Hispanic white), 55.5% were low risk, 43.1% moderate risk, and 1.4% high risk. Hallucinogen ASSIST scores correlated positively with alcohol (r=.39) and cannabis (r=.35) ASSIST scores (ps<.001). ANOVAs showed higher hallucinogen risk was associated with worse scores on all five mental health outcomes (ps<.001). After adjusting for alcohol and cannabis use, age, and sex, hallucinogen risk explained less than 1% of unique variance in each outcome, while cannabis use explained more variance. The high-risk group no longer differed from the low-risk group for psychological distress, loneliness, and suicide risk, but remained impaired on flourishing and resilience even after polysubstance adjustment. Psychological distress (OR=1.04) and suicide risk (OR=1.11) were the strongest correlates of mental health service use. After controlling for symptom severity, alcohol and cannabis use were no longer significant. The high-risk group was 72% less likely to have received mental health services than the low-risk group (OR=0.28, p<.001). Moderate risk was not associated with IPV, but the high-risk group had six times the odds compared to low-risk group (OR=6.24, 95% CI [2.91, 13.39], p<.001).

Conclusion/Implications: These findings challenge assumptions that hallucinogen use is a primary contributor to poor mental health among college students. Most mental health differences across hallucinogen risk levels were explained by concurrent alcohol and cannabis use. However, the high-risk group remained distinct in functioning outcomes, service utilization, and IPV even after polysubstance adjustment, suggesting broader psychosocial vulnerability. Campus health settings should move beyond single-substance screening toward integrated polysubstance assessment to identify students with unmet clinical need.