Psilocybin Decriminalization
~6/100 overall harm score
In a multicriteria analysis of 20 drugs published in The Lancet, alcohol scored 72 out of 100 for overall harm while psilocybin mushrooms scored approximately 6, the lowest of all drugs studied, and the number most often cited in the case for decriminalization.
Nutt et al., The Lancet, 2010
8 criteria
DEA Schedule I factors; Johnson 2018 found psilocybin fails all 8
135,000
adults in Johansen 2015; no link to mental health problems found
+723%
rise in poison center calls for children under 12 since 2019 (Rockhill 2025)
Nutt et al., The Lancet, 2010
View as image ↗No serious policy question has only one side. The debate over decriminalizing psilocybin is argued with primary research on both sides, and understanding that research is more useful than choosing a team. This article presents the strongest version of each argument, the peer-reviewed case for decriminalization and the peer-reviewed concerns against it, without advocacy in either direction. For the federal legal context that makes city-level decrim the current strategy, see psilocybin's Schedule I status: history and controversy. For a tracker of where decrim policies currently exist, see psilocybin decriminalization city by city: a complete US tracker.
Key Takeaways
- Johnson and colleagues applied the DEA's own 8-factor Schedule I evaluation criteria to psilocybin and concluded it does not meet any of the criteria for Schedule I classification, co-authored by former FDA evaluator Jack Henningfield (Johnson 2018)
- Nutt and colleagues ranked 20 drugs on 16 harm criteria in The Lancet; alcohol scored 72/100 and psilocybin mushrooms scored approximately 6/100, the lowest of all drugs studied (Nutt 2010)
- A national survey of 135,000+ US adults found no association between lifetime psychedelic use and mental health problems, suicidal behavior, or psychiatric treatment, directly countering the safety argument against decriminalization (Johansen 2015)
- Rockhill and colleagues documented that psilocybin-related poison center calls for children under 12 rose 723% between 2019 and 2023, the strongest empirical argument against policies that permit access without a regulated framework (Rockhill 2025)
- Schonholz and colleagues identified consent, liability, and equity issues that decriminalization alone does not resolve, noting that removing criminal penalties and creating a safe framework are different problems (Schonholz 2024)
- The honest framing: both sides draw on real evidence; the debate is not about whether psilocybin is harmful (it ranks low) but about what level of access, to whom, and under what safeguards
Arguments For: The DEA's Own Criteria Applied to Schedule I
The most rigorous peer-reviewed argument for decriminalizing psilocybin comes from a 2018 paper in Neuropharmacology by Johnson and colleagues.[1] The paper is unusual: it applied the Controlled Substances Act's own 8-factor evaluation framework to psilocybin to assess whether the drug actually meets the criteria for Schedule I classification.
The DEA's Schedule I criteria require that a substance have high abuse potential, no currently accepted medical use, and a lack of accepted safety for use under medical supervision. Johnson and his co-authors (including Roland Griffiths of Johns Hopkins and Jack Henningfield, who previously worked for the FDA evaluating drug abuse potential) assessed psilocybin against all eight factors the DEA uses when scheduling substances.
Their conclusion: psilocybin does not meet any of the Schedule I criteria. Abuse potential is low and does not escalate to compulsive drug-seeking behavior the way Schedule I drugs typically do. Accepted medical use was developing even in 2018, with clinical trials underway for depression and addiction. Safety under medical supervision was well-characterized. The paper did not advocate for any particular legal outcome. It applied the regulatory framework as written and reported where psilocybin landed.
This matters for the decriminalization debate because the argument it supports is internally consistent: if psilocybin was scheduled in 1970 based on political considerations rather than systematic pharmacological review, and if pharmacological review now finds it does not meet Schedule I criteria, then criminal penalties for possession are built on a classification that does not reflect the drug's actual properties. For the legal history behind that 1970 classification, see psilocybin and Schedule I: the legal history and path to rescheduling.
Arguments For: The Harm Comparison That Launched a Thousand Policy Papers
In 2010, Nutt and colleagues published a multicriteria decision analysis in The Lancet that ranked 20 commonly used drugs on 16 harm criteria: nine harms to the individual user and seven harms to others, including crime, family harm, and economic cost.[2]
Alcohol scored 72 out of 100, ranking as the most harmful drug overall when harms to others were included. Heroin scored 55, crack cocaine 54. Psilocybin mushrooms scored approximately 6, the lowest score among all 20 drugs studied, marginally below LSD (7) and ecstasy (9).
The framing this creates for decriminalization advocates is simple: if the goal of drug law is harm reduction, then criminal penalties are most logically directed at high-harm substances. Psilocybin's harm profile, by the most comprehensive multicriteria analysis available, places it at the opposite end of the spectrum from the drugs that most justify enforcement resources.
This argument does not require claiming psilocybin is harmless. It requires only that the legal consequences be proportionate to the harm profile, and that a drug scoring 6/100 be treated differently than a drug scoring 72/100 that is legally sold in supermarkets.
Arguments For: The Population Safety Data
The Nutt 2010 ranking addressed aggregate social harm. Two subsequent studies focused specifically on whether psychedelic use predicts harm at the individual level.
Johansen and Krebs, in a 2015 study published in the Journal of Psychopharmacology, analyzed data from a nationally representative US sample of more than 135,000 adults.[3] They examined whether lifetime psychedelic use was associated with mental health problems, suicidal ideation, psychiatric treatment, or suicidal behavior. After adjusting for confounding variables, they found no significant association in any direction.
This finding does not establish that psychedelic use is safe for all people in all contexts. It establishes that in the general population, having used a psychedelic at least once is not a statistical predictor of mental health harm. The primary argument decriminalization opponents make about personal harm risk, that psychedelics cause psychiatric injury in the general population, is not supported by population-level data.
The clinical trial safety record reinforces this. A 2025 systematic review by Freitas and colleagues, published in the Australian and New Zealand Journal of Psychiatry, synthesized the adverse event data from psilocybin-assisted therapy trials.[4] Their finding: most adverse effects in controlled settings were transient and mild, and no deaths were attributed to psilocybin's pharmacological effects across the reviewed trials. For the full physiological safety picture, see how safe is psilocybin? the complete safety research.
Arguments Against: The Children Problem
The strongest empirical argument against decriminalization policies in their current form comes from the same 2025 Annals of Internal Medicine study that decriminalization advocates cite for the adult use trend data.
Rockhill and colleagues found that psilocybin-related calls to US poison control centers for children under 12 rose 723% between 2019 and 2023, the same period during which the US decriminalization wave spread from Denver and Oakland across more than fifteen cities.[5] Calls for adolescents rose 317%.
These children are not using psilocybin intentionally. They are being accidentally exposed, almost certainly through contact with psilocybin products kept in homes where adults are using them. This is not an argument that psilocybin harms adults. It is an argument that decriminalization without a regulated storage and access framework creates access pathways to populations for whom no one is arguing psilocybin should be available.
The counter-argument is that regulation, not decriminalization reversal, is the appropriate response: legal alcohol and cannabis have packaging standards and child-resistant storage requirements precisely because prohibition did not prevent access. But Rockhill's data represents the honest current-state case against policies that lower the barriers to access without simultaneously creating protective infrastructure.
Bhave and colleagues published a direct analysis of what happened after US city-level decriminalization measures passed, in the Journal of Psychoactive Drugs in 2025.[7] Their work provides the most direct empirical evidence on what decriminalization actually produces in use patterns and downstream effects.
Arguments Against: What Decriminalization Doesn't Fix
A 2024 paper in the Journal of the American Academy of Psychiatry and the Law by Schonholz and colleagues identified three categories of problem that decriminalization alone does not address.[6]
The first is consent and information. Removing criminal penalties says nothing about ensuring people have accurate information about dosing, contraindications, or what to do when an experience becomes overwhelming. In a legal market, product labeling and informed consent requirements create that infrastructure. Decriminalization does not.
The second is equity. Lowest-priority decriminalization resolutions are advisory, not binding. Enforcement patterns in decriminalized jurisdictions can still reflect racial and socioeconomic disparities, because the underlying law has not changed, only the policy priority around it. A Black resident of a decriminalized city and a white resident may face very different practical enforcement realities even under identical formal policies. Removing criminal penalties entirely through legalization eliminates the discretion that creates disparate enforcement.
The third is liability and harm attribution. If someone experiences a serious adverse event (psychological crisis, accident during an experience, medical emergency) in a decriminalized context, there is no framework for accountability, clinical response coordination, or harm documentation. Clinical trial frameworks include monitoring, screening, and trained supervision. The recreational context under decriminalization has none of that infrastructure.
A 2023 JAMA Psychiatry analysis by Siegel and colleagues mapping the landscape of psychedelic legislative reform noted that these gaps are the primary regulatory challenge between decriminalization and more complete frameworks like therapeutic access models.[8] Oregon and Colorado's regulated service center models attempt to address them; city-level decriminalization policies do not.
The Summary Table: What Each Side Cites
| Argument | Evidence | Source |
|---|---|---|
| Psilocybin fails the DEA's own Schedule I criteria | Applied 8-factor CSA analysis | Johnson et al., Neuropharmacology, 2018 |
| Psilocybin is the lowest-harm drug in multicriteria analysis | Scored ~6/100 vs. alcohol 72/100 | Nutt et al., The Lancet, 2010 |
| No population-level mental health harm link | 135,000+ adults, no association | Johansen & Krebs, J Psychopharmacol, 2015 |
| No deaths in controlled clinical trials | Systematic safety review | Freitas et al., ANZJ Psychiatry, 2025 |
| Children's accidental exposures up 723% | Poison center national data | Rockhill et al., Ann Intern Med, 2025 |
| Decrim leaves consent, equity gaps unaddressed | Legal/ethics analysis | Schonholz et al., JAAPL, 2024 |
| Use increased significantly post-decrim nationally | Multisource observational study | Rockhill et al., Ann Intern Med, 2025 |
| Regulatory gaps between decrim and therapeutic access | Legislative reform map | Siegel et al., JAMA Psychiatry, 2023 |
The argument for decriminalization is strongest on the pharmacological and harm-comparison evidence. The argument against is strongest on the question of unintended access by non-target populations and the absence of a protective framework in decriminalized settings. Whether decriminalization is a good policy depends partly on which problem you are trying to solve and how you weigh those evidence types. For a deeper look at the policy models beyond decriminalization, see decriminalization vs. legalization: what's the difference? and Denver, Oakland, and beyond: the decriminalization wave.
The Bottom Line
The case for psilocybin decriminalization rests on peer-reviewed evidence: pharmacological analyses showing it fails Schedule I criteria (Johnson 2018), harm rankings placing it as the lowest-harm drug studied (Nutt 2010), and population surveys showing no mental health link (Johansen 2015). The case against rests on different evidence: a 723% rise in children's poison center calls post-decrim (Rockhill 2025) and identified gaps in consent infrastructure, equity, and harm accountability that decriminalization alone does not resolve (Schonholz 2024). This is a policy debate where both sides have primary research, which is why presenting both without advocacy is the more useful service.
Frequently Asked Questions
Sources & References
- 1RTHM-00514·Johnson, Matthew W et al. (2018). “The abuse potential of medical psilocybin according to the 8 factors of the Controlled Substances Act..” Neuropharmacology.Study breakdown →PubMed →↩
- 2RTHM-00356·Nutt, David J et al. (2010). “Drug harms in the UK: a multicriteria decision analysis..” Lancet (London.Study breakdown →PubMed →↩
- 3RTHM-00696·Johansen, Pål-Ørjan et al. (2015). “Psychedelics not linked to mental health problems or suicidal behavior: a population study..” Journal of psychopharmacology (Oxford.Study breakdown →PubMed →↩
- 4RTHM-02083·Freitas, Rosana R et al. (2025). “The safety of psilocybin-assisted psychotherapy: A systematic review..” The Australian and New Zealand journal of psychiatry.Study breakdown →PubMed →↩
- 5RTHM-02169·Rockhill, Karilynn M et al. (2025). “The Rise of Psilocybin Use in the United States: A Multisource Observational Study..” Annals of internal medicine.Study breakdown →PubMed →↩
- 6RTHM-01983·Schonholz, Stephanie M et al. (2024). “Legal and Ethics Concerns of Psilocybin as Medicine..” The journal of the American Academy of Psychiatry and the Law.Study breakdown →PubMed →↩
- 7RTHM-02058·Bhave, Ashutosh (2025). “Magic of the Mushrooms: Effects of Psilocybin Decriminalization..” Journal of psychoactive drugs.Study breakdown →PubMed →↩
- 8RTHM-01791·Siegel, Joshua S et al. (2023). “Psychedelic Drug Legislative Reform and Legalization in the US..” JAMA psychiatry.Study breakdown →PubMed →↩