Psilocybin for Anorexia Nervosa: Evidence, Risks, and Research Gaps

Systematic Review Finds Early Promise for Psilocybin in Anorexia Nervosa

A recent systematic review registered with PROSPERO (CRD420261479321) and published on November 9, 2026, synthesizes the current clinical trial evidence for psilocybin-assisted interventions in adults with anorexia nervosa. The review identified only two prospective, uncontrolled trials involving a total of 31 participants. Across these studies, psilocybin administration was associated with improvements in eating-disorder psychopathology, motivation for recovery, body-image anxiety, and related psychiatric symptoms. Some benefits persisted up to 12 months post-intervention, suggesting possible durability of effect.

However, the evidence base is extremely limited. Both included studies lacked randomized comparators and featured small, highly selected samples, precluding causal inference or generalizability. No quantitative meta-analysis was possible due to heterogeneity and sample size. The review, conducted in accordance with PRISMA 2020 guidelines, underscores that while psilocybin shows preliminary clinical signals, robust efficacy cannot be established at this stage.

Mechanisms and Clinical Context: Why Psilocybin for Anorexia?

Anorexia nervosa is a severe psychiatric disorder with high morbidity and mortality, and few effective pharmacological treatments. Psilocybin, a serotonergic psychedelic, has been hypothesized to disrupt maladaptive cognitive and emotional patterns through 5-HT2A receptor agonism and modulation of neural network connectivity. This neurobiological rationale has driven interest in psilocybin-assisted therapy as a potential intervention for eating disorders, particularly where conventional therapies have failed.

The included trials reported improvements in both core eating-disorder symptoms and comorbid anxiety, as well as increased motivation for recovery. Notably, some participants maintained these gains for up to a year. However, the studies' open-label designs and lack of control groups mean placebo effects and expectancy biases cannot be ruled out. The review notes that the heterogeneity in outcome measures and participant selection further complicates interpretation of the findings.

Policy and Research Implications: The Need for Rigorous Trials

The current evidence base for psilocybin in anorexia nervosa is insufficient for clinical or regulatory adoption. The review calls for well-powered, randomized controlled trials (RCTs) with rigorous medical monitoring and extended follow-up. Such studies are essential to determine whether psilocybin offers true therapeutic benefit, to characterize its safety profile, and to identify which patient populations may benefit—or be at risk.

Notably, the review highlights a concrete research gap: the absence of trials that include medically compromised or severely underweight individuals, who represent a substantial proportion of those affected by anorexia nervosa. This exclusion reflects ethical and safety concerns but also limits the generalizability of current findings. Future studies must grapple with the challenge of balancing scientific rigor, patient safety, and real-world clinical relevance.

• Regulatory agencies such as the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) are unlikely to consider psilocybin for anorexia nervosa without data from large, controlled trials.
• Funding bodies and institutional review boards will need to weigh the risks of psychiatric destabilization and metabolic complications against the potential for innovation in a field with few options.

Risks, Unknowns, and Safety Concerns

Psilocybin administration in the reviewed trials was generally tolerated, but serious adverse events were reported, including acute psychiatric episodes and hypoglycemia. These risks are particularly salient in anorexia nervosa, where medical fragility and psychiatric comorbidity are common. The review emphasizes that rigorous medical monitoring is essential in future studies, especially given the potential for unpredictable physiological responses in undernourished individuals.

Another underappreciated risk is the potential for psilocybin to exacerbate psychiatric symptoms or trigger relapse in vulnerable patients. The review notes that current studies have not systematically assessed long-term safety or relapse rates, leaving significant gaps in our understanding of risk-benefit balance.

Looking Forward: Next Steps for Research and Clinical Practice

The systematic review concludes that psilocybin-assisted interventions show early promise for adults with anorexia nervosa, but the evidence remains preliminary and insufficient for clinical use. The field now faces several key challenges:

• Designing and funding large, randomized controlled trials with robust safety protocols
• Developing inclusion criteria that reflect the diversity and medical complexity of real-world patients
• Establishing standardized outcome measures for both efficacy and safety
• Engaging regulatory agencies early to align trial designs with future approval pathways

One non-obvious implication is that future trials may need to incorporate adaptive designs or staged enrollment to safely include higher-risk patients, rather than excluding them entirely. This approach could help bridge the gap between scientific rigor and clinical relevance, ultimately informing both regulatory decisions and real-world practice.

By Dr. Julia Bennett, MD, PhD (psychiatrist, clinical researcher). Reviewed by Dr. Samuel Lee, MD, MSc, on 2026-11-10. We conduct independent reviews of primary sources and trial registries, including PROSPERO and PubMed, and cite only original data and regulatory filings.