Hallucinogen use among young adults ages 19-30 in the United States: Changes from 2018 to 2021

Non-medical hallucinogen use is linked with elevated risks including substance use disorders, injury (including self-harm) and anxiety, and young adults are an age group at particularly high risk. The authors note that renewed clinical interest in psychedelic and hallucinogenic compounds — and increasing therapeutic visibility — may reduce perceived harms and expand demand and diversion for non-medical use. Although national surveys suggested increases in some hallucinogen use among US adults in 2018–2019, patterns specifically among young adults and for non-LSD hallucinogens in more recent years remained incompletely described. Keyes and colleagues therefore set out to document changes in past‑12‑month hallucinogen use among US young adults aged 19–30 years from 2018 through 2021. The study aimed to compare trends for LSD and for other hallucinogens (examples given include psilocybin/"shrooms", mescaline, peyote and PCP), to examine frequency of use, and to identify demographic correlates of use over this period. The investigators framed this surveillance as important for public health monitoring given potential increases in non-medical availability and evolving use patterns such as microdosing.

Data came from the Monitoring the Future (MTF) study, which begins with nationally representative 12th-grade surveys and follows a subset of respondents into young adulthood. The extracted text does not clearly report the number of unique participants in the analytic sample in the Methods sections, but for regression analyses the authors report 16,485 datapoints for the LSD outcome and 16,490 datapoints for the non-LSD hallucinogen outcome, reflecting repeated measures across years. Item‑level missing data were small (395 respondents missing the LSD item and 389 missing the non‑LSD hallucinogen item) and those cases were removed from analyses. Analyses were not pre-registered and the authors followed STROBE guidance for cross-sectional data. Hallucinogen use measures were self-reported past‑12‑month use. Participants were asked separately about frequency of LSD use and about frequency of 'hallucinogens other than LSD' with response options on an ordinal frequency scale from 'none' to '40+'. Outcomes analysed were any past‑year use (dichotomous) for LSD and for other hallucinogens, and mean frequency of use occasions in the past 12 months. Demographic covariates included year of survey, age (19–24 versus 25–30 implied in results), sex (male, female), race/ethnicity (white, black, Hispanic, Asian, other) and parental education (at least one parent with a college degree versus none) used as a proxy for socio-economic status. Statistical procedures first estimated annual prevalence and standard errors using complex survey‑weighted frequency methods that account for sampling design and attrition via attrition weights. The authors then used logistic regression with repeated‑measures survey procedures to model associations between year and the demographic covariates with each dichotomous outcome. Multiplicative two‑way interactions between year and each demographic factor (age, sex, race/ethnicity, parental education) were also tested. Confidence intervals are reported for key estimates.

Prevalence of past‑year use of hallucinogens other than LSD increased between 2018 and 2021. Overall prevalence rose from 3.4% (95% CI = 2.8–4.1) in 2018 to 6.6% (95% CI = 5.5–7.6) in 2021. Among males the prevalence increased from 4.3% (95% CI = 3.3–5.3) to 8.1% (95% CI = 6.4–9.9); among females it rose from 2.6% (95% CI = 1.8–3.3) to 5.2% (95% CI = 4.0–6.3). In logistic regression, the odds of non‑LSD hallucinogen use were 2.01 times higher in 2021 compared with 2018 (95% CI = 1.55–2.60). Demographic correlates for non‑LSD hallucinogen use included male sex (OR = 1.86, 95% CI = 1.52–2.26), lower odds for black versus white participants (OR = 0.29, 95% CI = 0.19–0.47) and slightly lower odds for those without a college‑educated parent (OR = 0.80, 95% CI = 0.64–0.99). For LSD specifically, prevalence was reported as more stable across the period: prevalence in 2020 was higher than in 2018 (OR = 1.26, 95% CI = 1.02–1.56) but prevalence in 2021 did not differ significantly from 2018 (OR = 1.14, 95% CI = 0.87–1.50). Correlates of LSD use paralleled those for non‑LSD hallucinogens: higher odds for males (OR = 1.81, 95% CI = 1.46–2.25), lower odds for black young adults versus white young adults (OR = 0.25, 95% CI = 0.15–0.43) and lower odds for those with no college‑educated parent (OR = 0.79, 95% CI = 0.62–0.99). Younger age (19–24 versus 25–30) was associated with higher odds of LSD use (OR = 1.36, 95% CI = 1.11–1.67). The extracted text indicates the authors examined frequency of use but does not present detailed numeric changes in mean frequency; in the Discussion the authors state that average frequency did not change even as the number of users rose.

Keyes and colleagues interpret their findings as evidence that non‑medical hallucinogen use among US young adults increased notably from 2018 to 2021, with prevalence of non‑LSD hallucinogens approximately twice as high in 2021 as in 2018. The rise was concentrated in products other than LSD, and the authors suggest that psilocybin/'shrooms are likely contributors because 'shrooms' have the highest prevalence among the non‑LSD category measured in MTF. At the same time, the average frequency of use occasions reportedly did not change, which the investigators read as indicating a growing population of young adults regularly using non‑LSD hallucinogens. The authors situate these results amid increasing therapeutic and public visibility of psychedelic compounds and note that such visibility may promote diversion, wider unregulated availability and changing perceptions of risk. Demographic patterns reported here showed higher use among males, higher use among white participants relative to black participants, and greater prevalence among those from households with higher parental education, which the authors use as an indicator of higher socio‑economic status. Several contextual points are raised. The increases in non‑LSD hallucinogen use occurred during the COVID‑19 pandemic years, and while the authors discuss pandemic‑related shifts in substance use motivations (for example, increased coping) they characterise the role of the pandemic in these trends as speculative. They also highlight emerging use modalities such as microdosing and note a lack of national surveillance data on such practices. Limitations acknowledged by the authors include the MTF design's initial sampling of 12th‑grade students — therefore excluding those who already dropped out of high school — and loss to follow‑up, although attrition weights were applied to mitigate bias. Strengths specified include the use of recent, nationally derived data to document changing patterns among young adults. The authors call for continued monitoring, further investigation of harms (including dependence, injury and consequences of co‑use with other psychoactive substances), and research into evidence‑based treatment and intervention approaches as therapeutic use of hallucinogens expands. The need for parallel surveillance in other countries and attention to novel psychoactive substances are also noted as priorities.