JAMA Psychiatry
November 5, 2025
Kent E. Hutchison, Judith Hooper, Hollis C Karoly
10 citations
Psilocybin mushroom use has sharply increased in the US, particularly among adults aged 19 to 50 years, with more than 7 million individuals reporting use in the past year. This trend has coincided with a substantial increase in poison control center calls related to psychedelics. Testing data from decriminalized regions indicate more than 20-fold variability in psilocybin potency and inconsistent levels of minor tryptamines across mushroom strains. Clinical trial data on synthetic psilocybin do not generalize to public use due to strict participant selection and controlled environments. Co-use with cannabis is common and may increase the risk of adverse events. The expanding use of unregulated psilocybin mushrooms, combined with high variability in composition and common co-use with other substances, raises urgent public health concerns.
Psychedelic medicine (New Rochelle, N.Y.)
December 1, 2024
Cianna J Piercey, Bethany A. Gray, Angelina Sung et al.
5 citations
A review of protective behavioral strategies (PBS) for psychedelic use outside clinical settings found that a culture of harm reduction exists within psychedelic communities. Identified strategies include careful drug acquisition, dosing, managing set and setting, bodily nourishment, planning for challenging experiences, and post-use integration. Although research is limited, emerging evidence suggests that using these strategies may reduce negative consequences. The review calls for better measurement tools and more studies to understand how PBS can support the growing number of people—8.5 million Americans over 12 reported past-year use in 2022—who use psychedelics nonclinically.
J Cannabis Res
July 11, 2024
Cianna J Piercey, Eleftherios Hetelekides, Hollis C Karoly
5 citations
Among attendees of festivals and concerts in Colorado, simultaneous use of cannabis and psychedelics is common, with many users reporting enhanced positive experiences such as deeper introspection and sensory amplification. However, a notable minority experience adverse reactions including anxiety, paranoia, and confusion. Qualitative interviews reveal that users often intentionally combine substances to modulate the psychedelic experience, but the lack of predictable outcomes and setting-related factors contribute to negative effects. The findings suggest that simultaneous use carries both potential benefits and risks that are influenced by dose, individual tolerance, and environmental context.
Substance abuse treatment, prevention, and policy
May 5, 2026
Katherine G. W. Hill, Cianna J Piercey, Hollis C Karoly et al.
Kava, a psychoactive plant from the Pacific Islands, is used for its anxiolytic and sedating effects. In a 2024 online survey of 368 adults who had used kratom, kava, tianeptine, or akuamma seed, 48.9% had used kava in their lifetime. Lifetime kava users were younger, more racially diverse, and more likely to be employed or in school. Kava was purchased online (40.6%) or in tea bars (31.7%). Users reported infrequent consumption (average 4.4 months per year, 9.1 days per month). Perceived effects included reduced general anxiety (33.7%), improved mood (32.9%), reduced social anxiety (25.5%), and sedation (23.4%). Only 11.7% viewed kava as habit-forming, and 51.7% saw it as an alcohol replacement. Kava use practices are diverse, and clinicians should be aware of its role in harm-reduction.
Harm Reduction Journal
March 2, 2026
Cianna J Piercey, Joseph Cameron, Riley Ahern et al.
Kratom, a psychoactive botanical, is increasingly used in the United States. A survey of 102 participants (average age 22.34 years, 39.2% women) recruited from ethnobotanical tea bars in Northern Colorado found that 75.5% had experienced at least one adverse reaction. Adverse reactions most commonly occurred when kratom was consumed on an empty stomach, with certain foods, without adequate hydration, or combined with other substances. Participants used strategies like stopping or pacing use, adjusting hydration and food intake, and resting to mitigate reactions, though the effectiveness of these techniques remains unknown. The findings suggest that contextual factors may contribute to adverse reactions, highlighting the need for more research to inform harm reduction and public health messaging.
Journal of Studies on Alcohol and Drugs
May 20, 2025
Mark A. Prince, Brandon Paez, Jessica L Morse et al.
American Indian (AI) and non-AI youth living on or near reservations show largely similar rates of using substances often grouped as 'other' (inhalants, MDMA, hallucinogens, prescription opioids, over-the-counter cold medicines), though some regional and sex-based differences emerge. In two regions, AI youth had higher odds of using any 'other' substance than non-AI youth, while in the Southeast and Northwest they were less likely to use prescription opioids and over-the-counter cold medicines, respectively. Males in the Southwest were more likely than females to use inhalants, hallucinogens, and tranquilizers. The Southern Plains region reported the highest prevalence of 'other' substance use overall. These patterns can guide targeted prevention and intervention.
Addiction Biology
January 1, 2022
Laurel P Gibson, Hollis C Karoly, Jarrod M. Ellingson et al.
Cannabis flower with both THC and CBD produces similar positive effects but less paranoia and anxiety than THC-dominant cannabis. In a naturalistic at-home study, 159 regular cannabis users were randomly assigned to one of three chemovars: THC-dominant (24% THC, 1% CBD), THC+CBD (9% THC, 10% CBD), or CBD-dominant (1% THC, 23% CBD). Plasma samples showed those using the CBD-dominant or THC+CBD chemovars had significantly less THC and more CBD than those using the THC-dominant chemovar. The THC+CBD chemovar yielded similar positive subjective effects but significantly less paranoia and anxiety compared to the THC-dominant chemovar, suggesting potential harm reduction from CBD.