Bold takeaway: Emergency hallucinogen use may foreshadow a significantly higher risk of future mania and bipolar disorder, a link uncovered in a large population study.
A study published in PLOS Medicine on December 2, 2025, analyzed hospital and emergency department data from Canada spanning 2008–2022 to examine whether people who sought urgent care for hallucinogen use faced greater odds of mania diagnoses or mania-related care in the following three years. The researchers compared 7,285 patients seen for hallucinogen-related emergencies or hospitalizations to 78,201 patients hospitalized for other reasons and to the general population.
Key findings show that individuals with an ED visit or hospitalization for hallucinogen use were six times more likely to receive treatment for mania within the next three years. They were also four times more likely to be diagnosed with bipolar disorder, relative to those hospitalized for non-hallucinogen-related causes. The level of risk for mania after hallucinogen-related care was similar to that observed after cannabis-related care, a context previously linked to mania risk. Notably, about two-thirds of those treated for hallucinogen-related issues had prior substance-use-related visits, and nearly half had prior mental-health-related visits.
The authors caution that, given the timing of the records, most cases likely involved non-medical use. The findings apply to people who required urgent health care and may not generalize to all hallucinogen users, especially those who never needed urgent care. Nevertheless, the authors suggest that hallucinogen use resulting in urgent care could be associated with an elevated risk of later mania or bipolar disorder. They emphasize that the observed association may reflect that individuals at higher baseline risk for mania or BD are more likely to end up in ED or hospital care after hallucinogen use, rather than proving a direct causal effect of the drugs themselves.
Daniel Myran, the study’s senior author, states, “Our study shows a strong association between hallucinogen use that necessitates ER or hospital care and future risk of mania and bipolar disorder.”
Coauthor Marco Solmi adds that these results illuminate the nuanced balance between therapeutic potential and safety in hallucinogen use. He notes the need for future research to identify predictors of beneficial versus harmful outcomes at the individual level.
Context and caveats
- Hallucinogen use has surged in both recreational and medical settings, including potential treatments for depression or PTSD.
- The current study cannot establish causation and focuses on a subset of users who required urgent care, not the broader population of hallucinogen users.
- The authors call for careful interpretation: the observed risk may reflect underlying vulnerability rather than a direct pharmacological effect of hallucinogens.
What this means for readers
If considering hallucinogen-based therapies or if someone you know has used hallucinogens and later experiences mood changes, discuss these risks with a healthcare professional. This study highlights that urgent-care users may carry a heightened risk profile for mania and BD, underscoring the importance of close monitoring and individualized risk assessment in both research and clinical practice.
Discussion prompts
- Do these findings imply a causal link between hallucinogen exposure and mania, or do they reflect pre-existing risk factors? What additional data would help differentiate these possibilities?
- How should clinicians balance potential therapeutic benefits with safety concerns in hallucinogen-assisted treatments for mood or trauma-related disorders?
- What safeguards or screening tools could identify individuals at higher risk for adverse mood outcomes when considering hallucinogen-based interventions?
