A new analysis suggests that while the use of psychedelic substances appears to be increasing in the United States, this trend has not resulted in a corresponding surge in emergency room visits or hospitalizations. The findings indicate that severe adverse events requiring hospital care for hallucinogens remain comparatively rare when measured against other substances like alcohol and opioids. This research was published in JAMA Network Open.
The cultural landscape regarding psychedelics is shifting rapidly in the United States. Changes in state and local laws regarding decriminalization are occurring alongside increased media attention on the potential therapeutic benefits of drugs like psilocybin and MDMA. Government agencies have granted breakthrough therapy designations to some of these substances, acknowledging their potential medical utility.
This changing landscape raises important safety questions for public health officials. It is necessary to understand whether increased availability and reduced stigma are leading to more adverse health outcomes in the general population. Jacob Steinle, a psychiatry resident, and Kevin Xu, an assistant professor at Washington University in St. Louis, led an investigation to address this gap.
“Hallucinogen use is increasing in recreational settings, and legislation around clinical use is evolving,” explained Steinle. “Prior to the study, relatively little was known about the safety of these substances in real-world settings beyond small clinical trials or theoretical risk assessments. We wanted to investigate the prevalence of hospitalizations associated with hallucinogens to address this knowledge gap.”
To address this, the research team designed a retrospective cohort study using large-scale administrative data. They utilized records from the Merative MarketScan Commercial and Multi-State Medicaid databases.
These databases provide a comprehensive view of healthcare claims from a diverse population across the country. The study period spanned seven years, covering data from 2016 through 2023. The investigators specifically focused on individuals between the ages of 16 and 64 years.
This age range captures the demographic groups most likely to engage in substance use. The researchers focused on identifying specific medical codes associated with hallucinogen-related disorders. They used the International Statistical Classification of Diseases, Tenth Revision, known as ICD-10.
Specifically, they looked for the code F16, which denotes hallucinogen-related issues in medical records. The team calculated the monthly rate of these admissions to track changes over time. They expressed this rate as a proportion of all substance-related emergency or hospital admissions.
This method allowed them to standardize the data and account for general fluctuations in healthcare utilization. To analyze trends over time, the authors employed Bayesian multiple change-point models. This statistical approach helps identify specific moments in time when a trend significantly changes direction.
The final dataset included 1,355,161 individuals who had at least one substance-related admission during the study period. Within this large cohort, 21,700 individuals had an admission specifically related to hallucinogens. This figure represents approximately 1.6 percent of the total group. The median age of individuals admitted for hallucinogen-related issues was 28 years.
“Despite fairly dramatic increases in hallucinogen use, we are not seeing a clear trend of increased hospitalizations—a proxy for severe adverse events,” Steinle told PsyPost. “Moreover, compared to substances like alcohol, amphetamines, and opioids, hallucinogens account for an incredibly small proportion of substance-related hospital admissions.”
The researchers also examined the insurance coverage of these patients. Approximately 60 percent of those with hallucinogen admissions were covered by Medicaid. Among the Medicaid enrollees where race and ethnicity data were recorded, the study provided a demographic breakdown. Non-Hispanic Black individuals accounted for 47.1 percent of these admissions. Non-Hispanic White individuals made up 44.1 percent, while Hispanic individuals accounted for 4.2 percent.
The investigators analyzed the psychiatric history of the patients in the six months leading up to the hospital admission. They found that 35 percent of the patients had a previously diagnosed mood disorder.
About 29.2 percent of the individuals had a diagnosis of anxiety prior to their admission. Additionally, nearly 15 percent had a diagnosis related to schizophrenia-spectrum disorders.
The study also noted the presence of other substance-related disorders in the patient histories. Roughly 18.9 percent of the patients had a history of non-nicotine substance disorders. This included issues with cannabis, alcohol, stimulants, and opioids.
The analysis of temporal trends revealed distinct patterns in the data. In January 2016, hallucinogen-related admissions made up 0.59 percent of all substance admissions. This proportion gradually increased over the next few years. The statistical models identified a period of growth until April 2020.
By early 2021, the monthly share had reached a peak of 1.18 percent. This suggests a rising burden of hallucinogen-related care leading up to the COVID-19 pandemic. Following the peak in early 2020, the trend reversed direction.
The rate of admissions began to decline through the year 2023. By the end of the study, the rates had leveled off. Despite the fluctuations, the overall numbers remained low relative to other substances.
The rates stabilized at a level slightly higher than where they started in 2016. However, they did not continue the upward trajectory that characterized the pre-2020 period. The study highlighted a significant disparity between hallucinogens and other drugs.
Alcohol-related admissions accounted for the largest share of visits, rising from approximately 48 percent to nearly 60 percent. Opioid admissions displayed a steady decline from roughly 29 percent to near 20 percent. Stimulant admissions grew from under 20 percent to surpass opioids by the end of the study.
Hallucinogens consistently accounted for a very minor percentage of the total admissions. This context provides evidence that the acute public health burden of hallucinogens is relatively low.
“The results were largely consistent with existing clinical trial data showing very low rates of adverse effects such as substance-induced psychosis,” Steinle said. “What is striking, however, is just how infrequent these events appear to be compared to other substances that can trigger psychotic episodes, such as cannabis and stimulants.”
However, adverse events may occur that do not result in a hospital visit. People experiencing difficult psychedelic experiences may be managed by friends or sitters outside of medical settings. Consequently, hospital data likely captures only the most severe reactions. Because of this, the true prevalence of adverse effects could be higher than hospital records suggest.
“While we did not observe a substantial increase in adverse events related to hallucinogens despite rising use, this does not mean these substances are safe in recreational contexts,” Steinle said.
Looking forward, the researchers plan to investigate the dominance of alcohol in substance admissions more thoroughly. They intend to compare alcohol-related trends with those of cannabis.
“The incidental, but noteworthy, finding regarding alcohol’s increasing prevalence in substance-related admissions has prompted us to investigate this trend more closely, specifically comparing and contrasting its use with cannabis, when stratifying by age,” Steinle said. “We also have ongoing work examining how certain states are implementing psychedelic-assisted psychotherapy and evaluating the rigor of their client screening processes.”
The study, “Trends in Hallucinogen-Related Emergency Department and Hospital Admissions, 2016 to 2023,” was authored by Jacob T. Steinle, Lisa Gong, Joanna L. Buss, Suraj Shankar, Joshua S. Siegel, Leopoldo J. Cabassa, Ruth Ling, Regina Huang, Danielle R. Adams, Patricia Cavazos-Rehg, Arpana Agrawal, Ginger E. Nicol, Richard Grucza, R. J. Waken, and Kevin Y. Xu.
