When people point to Oregon Psilocybin Services (OPS) and say adverse events are “rare,” it can sound like psilocybin is virtually risk-free. But the truth is more complicated. The way adverse events have been defined, collected, and reported have potentially overlooked important outcomes that can affect a person’s healing journey.

 

 

Narrow Definitions Leave Out Real-World Problems

 

Oregon Psilocybin Services (OPS) counts an adverse event if it requires emergency services, medical attention, or hospitalization, or if it is reported within 72 hours of the session (OHA, 2025a). Unfortunately, this leaves out important adverse effects many people may experience:

 

  • Panic attacks or severe anxiety that don’t lead to an ER visit but still destabilize
  • Insomnia or mood swings that linger for days, interfering with work, relationships, and recovery
  • Persistent emotional flattening that dulls connection or motivation, making integration harder

 

These outcomes may not make it into official statistics. But for someone in the middle of them, they are very real.

 

 

Missed Risks From Medication and Health Interactions

 

OPS requires clients to list their prescriptions and supplements (OHA, 2025b), but there is no requirement for a pharmacologic review of those medications or conditions. That means facilitators are left to interpret complex risks on their own. This gap can directly affect outcomes. For example:

 

  • Someone who is immunocompromised consumes mushrooms contaminated with bacteria or mold. They later develop a serious infection but never realize it came from the product. Pharmacologic review would have flagged this and ensured use of a high-quality, tested source with low contamination risk.
  • A client on a medication or substance that inhibits UGT1A9 or 1A10 enzymes unknowingly boosts psilocybin to supratherapeutic levels, leading to an overwhelmingly difficult journey. Despite skilled facilitator support, they continue to struggle afterward with heightened anxiety and dysphoria. This is a pharmacokinetic complication that may have been preventable with review.
  • In a group session, someone taking multiple medications that cause dizziness, sedation, or orthostatic hypotension tries to stand mid-journey, falls, and sustains a lasting injury. The adverse event would unlikely be attributed to psilocybin in adverse event reporting, but the combination of medications and psilocybin probably contributed to the poor outcome, and those risks could have been reduced with pharmacologic review.

 

When these problems arise, they rarely trigger emergency services, meaning they’re missed in adverse event reporting, but they can seriously undermine safety and healing.

 

 

Passive Reporting Underestimates the True Rates

 

The updated OPS forms rely on clients to self-report difficulties (OHA, 2025c). But many people won’t report an “incident” if they think their struggle is just part of the process, or if they worry about stigma. Without proactive follow-up, delayed or moderate harms and complications can slip through the cracks. Recent real-world research shows that approximately 1 out of 4 US adults who used psilocybin with the previous 12 months disagree or strongly disagree that psilocybin improved their mental or physical health (Rocky Mountain Poison & Drug Safety, 2025). Further, safety concerns with psychedelics can appear days or weeks after dosing, not just in the first 72 hours (Johnson et al., 2019).

 

 

Why Pharmacologic Review Matters

 

These blind spots add up to a misleading impression that may overestimates the true safety of psilocybin services. In reality, OPS data may be missing a meaningful share of risks, particularly those tied to drug interactions, health conditions, and under-recognized psychological outcomes. Pharmacologic review and medication management can help close this gap. By identifying and managing interaction risks before dosing, we can reduce complications, improve safety, and ultimately support deeper, more stable healing outcomes.

 

 

Oregon, Colorado, and Other States: Recognizing Pharmacologic Impact, But Gaps Remain

 

Oregon’s safety updates and ongoing information gathering show that the state is aware of how medications and health conditions can influence psilocybin experiences, even though OPS currently provides limited guidance on managing these interactions (OHA, 2025c). Colorado has similarly acknowledged potential medication effects, listing certain medications to screen for and suggesting pharmacist consultation within its screening forms (Colorado DORA, 2025). However, guidance remains limited, offering little direction on how to tailor risk management to individual clients. Adverse event reporting definitions and systems in both states continue to miss subtler pharmacologic effects that may contribute to delayed psychological or physical complications. Nevada and several other states have approved or are considering legislation to regulate psilocybin therapy, but these programs are still in early stages (Nevada Legislature, 2025). Across all these efforts, real-world harms from unrecognized drug interactions, dosage amplifications, or health-condition-related vulnerabilities can still go unreported. This underscores the ongoing need to carefully monitor adverse events and implement personalized pharmacologic review to improve safety and optimize therapeutic outcomes.

 

 

References

 

  1. Oregon Health Authority. (2025a). Client Adverse Reactions. Oregon Psilocybin Services. Retrieved from https://www.oregon.gov/oha/PH/PREVENTIONWELLNESS/Documents/Client-Adverse-Reactions.pdf
  2. Oregon Health Authority. (2025b). Guidance on Administrative Rules. Oregon Psilocybin Services. Retrieved from https://www.oregon.gov/oha/PH/PREVENTIONWELLNESS/Documents/OPS-Guidance-on-Administrative-Rules.pdf
  3. Oregon Health Authority. (2025c). Information for Licensed Facilitators. Oregon Psilocybin Services. Retrieved from https://www.oregon.gov/oha/ph/preventionwellness/pages/psilocybin-information-for-licensed-facilitators.aspx
  4. Oregon Health Authority. (2025d). Rapid Evidence Review and Recommendations. Oregon Psilocybin Advisory Board. Retrieved from https://www.oregon.gov/oha/PH/PREVENTIONWELLNESS/Documents/Oregon%20Psilocybin%20Advisory%20Board%20Rapid%20Evidence%20Review.pdf
  5. Rocky Mountain Poison & Drug Safety. Use of Psychedelic Substances in the United States, 2024 (RMPDS Publication No. RMPDS-2025-I-01). Rocky Mountain Poison & Drug Safety, Denver Health and Hospital Authority; 2025. Accessed [date you accessed]. https://www.rmpds.org/nsiht
  6. Johnson M, Richards W, Griffiths R. Human hallucinogen research: guidelines for safety. J Psychopharmacol. 2008;22(6):603-620. doi:10.1177/0269881108093587
  7. Colorado Department of Regulatory Agencies, Division of Professions and Occupations. Colorado Natural Medicine session forms. Accessed September 14, 2025. https://dpo.colorado.gov/NaturalMedicine/Forms
  8. Nevada Legislature. AB 378: Bill Text. 83rd Sess. Nevada Legislative Counsel Bureau; 2025. Accessed September 14, 2025. https://www.leg.state.nv.us/App/NELIS/REL//83rd2025/Bill/12520/Text

 

 

If you would like to cite this article, copy the format you need:

 

AMA (11th ed.)
Speer K. Why Oregon’s “Rare” Adverse Event Findings May be Missing the Full Picture. PharmD Consult. Published September 26, 2025. Accessed [add current month, day, year, remove brackets]. https://psychedelicinteraction.com/pharmd-consult

 

APA (7th ed.)
Speer, K. (2025, September 26). Why Oregon’s “Rare” Adverse Event Findings May be Missing the Full Picture. PharmD Consult. https://psychedelicinteraction.com/pharmd-consult. Accessed [add current month, day, year, remove brackets].

 

Chicago (17th ed., author-date citation)
Speer, Kristin. 2025. “Why Oregon’s “Rare” Adverse Event Findings May be Missing the Full Picture.” PharmD Consult, September 26, 2025. Accessed [add current month, day, year, remove brackets]. https://psychedelicinteraction.com/pharmd-consult.

 

MLA (9th ed.)
Speer, Kristin. Why Oregon’s “Rare” Adverse Event Findings May be Missing the Full Picture. PharmD Consult, 26 Sept. 2025. Accessed [add current day, then month abbreviated, year, remove brackets]. https://psychedelicinteraction.com/pharmd-consult.