New Study Estimates Over 5.5 Million U.S. Adults Use Hallucinogens

According to a recent study by experts at Columbia University Irving Medical Center and Mailman School of Public Health, use of hallucinogens has reduced among teenagers between the ages of 12 and 17 but usage has grown overall since 2015, especially among people 26 and older. In the United States, it is projected that 5.5+ million individuals took hallucinogens in the previous year, up from 1.7 percent of those aged 12 and older in 2002 to 2.2 percent in 2019.

LSD usage grew overall and across all age categories between 2002 and 2019, with the percentage for individuals aged 18 to 25 going from 0.9 percent in 2002 to 4 percent in 2019. Between 2002 and 2019, PCP consumption declined, as did Ecstasy use after 2015.

For the first time, a rigorous statistical analysis of changes in the prevalence of hallucinogen usage overall and by age group during the last 20 years is presented in this study. The peer-reviewed journal Addiction posts the results online.

The researchers examined information from the National Survey on Drug Use and Health (NSDUH) for individuals 12 years of age and older from 2002 to 2019 to estimate changes in hallucinogen use in the general U.S. population.

The majority of psychoactive substances classified as Schedule I in the United States are hallucinogens, which include "classic" psychedelics like LSD. Using these substances carries a risk of negative side effects like anxious reactions, confusion, acute delusional states, and a protracted feeling of fear and dread. A higher risk of unfavorable autonomic, endocrine, cardiovascular, and neurological consequences, such as increased blood pressure, heart rate, appetite loss, tremors, and seizures, is linked to the use of LSD, Ecstasy, and numerous other hallucinogens. Despite having negative effects that are comparable to those of LSD and ecstasy, PCP is one of the most hazardous hallucinogens and is known to provoke angry and violent actions that may inflict trauma.

Ofir Livne, MD, MPH, the study's first author and a postdoctoral fellow in the department of epidemiology at Columbia Mailman School, said, "While new findings suggesting benefits from the use of certain hallucinogens among a range of cognitive areas are being published at a rapid rate, there are still gaps in knowledge regarding safe hallucinogen use, and evidence for potential adverse effects even with professionally supervised use that warrant attention."

Overall and among respondents aged 12 to 17, the incidence of 12-month LSD usage grew significantly from 2002 to 2019. However, across all age categories and over the years 2002–14, the prevalence of substantial risk for frequent LSD use considerably declined.

According to Deborah Hasin, PhD, professor of epidemiology (in psychiatry) at the Columbia University Irving Medical Center and senior author, "our finding of an increased trend in 12-month LSD usage, overall and by age, reflects our finding of a declining trend in perception of LSD as harmful." "Some hallucinogens may have seen an upsurge in usage in recent years due to factors such as changes in risk perception, the specific sorts of drugs accessible, and anticipation of favorable benefits of "microdosing," among others."

Given the recent media attention indicating that an increasing number of adults may be reporting positive effects of "microdosing" and anticipating therapeutic benefits of hallucinogens without side effects, Livne claims that "our findings merit a comprehensive examination of time trends and motives for hallucinogen frequency and quantity of use."

Researchers, clinicians, and policymakers should pay more attention to the rising rates of unsupervised hallucinogen use among the general public, according to Hasin. "In light of popular media reports of a forthcoming 'psychedelic revolution' with commercialization and marketing that may further reduce the public perception of any risk," she said. Our findings show that such usage is a significant public health issue and that preventive measures are necessary given the growing possibility of unsupervised hallucinogen use.

Dvora Shmulewitz of the Columbia University Irving Medical Center's Department of Psychiatry and Claire Walsh of the New York State Psychiatric Institute are the co-authors.

The study was supported by the National Institute on Drug Abuse (DA031099).