Psilocybin and Eating Disorders: Emerging Evidence for Anorexia and Bulimia

Eating disorders (EDs) represent some of the most challenging and life-threatening mental health conditions, with anorexia nervosa (AN) carrying the highest mortality rate among all psychiatric disorders [Rodan et al., 2021]. Traditional treatments, including cognitive-behavioral therapy (CBT), nutritional rehabilitation, and pharmacotherapy with selective serotonin reuptake inhibitors (SSRIs), often yield limited long-term success, with recovery rates hovering around 30-40% and high rates of relapse [Koning & Brietzke, 2024]. This persistent treatment gap underscores an urgent need for innovative therapeutic approaches.

Against this backdrop, the re-emergence of psychedelic-assisted psychotherapy, particularly with psilocybin, offers a beacon of hope. Psilocybin, the psychoactive compound found in certain species of mushrooms, is being investigated not as a standalone cure, but as a potential catalyst to enhance the efficacy of psychotherapy by fostering psychological flexibility and enabling deeper emotional processing that conventional methods often struggle to achieve [Koning & Brietzke, 2024].

Why Eating Disorders Are So Hard to Treat: The Role of Cognitive Rigidity

Eating disorders are far more than just issues with food; they are deeply rooted in distorted self-perception, an intense need for control, and a compromised sense of identity. A hallmark feature of AN, for instance, is profound cognitive rigidity—an unwavering adherence to beliefs about one\'s body and eating habits, even in the face of overwhelming contradictory evidence [Koning & Brietzke, 2024]. This inflexibility makes it incredibly difficult for individuals to challenge their disordered thoughts and behaviors.

Neurobiological studies provide insight into this rigidity. Research indicates that individuals with AN often exhibit abnormally high activity in the default mode network (DMN), a brain network associated with self-referential thought and rumination. Concurrently, there\'s often reduced density of serotonin 2A (5-HT2A) receptors in the prefrontal cortex, a region critical for executive function and cognitive control [Koning & Brietzke, 2024]. These neurobiological characteristics are particularly relevant because psilocybin directly modulates both DMN activity and 5-HT2A receptor function, suggesting a plausible mechanism for its therapeutic potential in EDs.

Psilocybin\'s Mechanism of Action: Rewiring the Brain for Flexibility

Psilocybin, a classical psychedelic, is structurally similar to serotonin. Upon ingestion, it is metabolized into psilocin, which then acts as a potent agonist at 5-HT2A serotonin receptors in the brain [Koning & Brietzke, 2024]. This interaction leads to a cascade of neurophysiological changes:

• Modulation of Brain Networks: Psilocybin significantly decreases activity in the DMN, which is often hyperactive in conditions characterized by rigid thought patterns, including EDs. Simultaneously, it increases connectivity between various brain networks, fostering a state of enhanced global brain connectivity and cognitive flexibility [Dallery et al., 2026].
• Enhanced Neuroplasticity: Psilocybin promotes synaptic plasticity, essentially helping the brain form new connections and pathways. This can be crucial for individuals with EDs to overcome deeply ingrained maladaptive beliefs and behaviors [Koning & Brietzke, 2024].
• REBUS Model: The RElaxed Beliefs Under pSychedelics (REBUS) model posits that psychedelics like psilocybin "loosen" rigid thinking and prior expectations, allowing for a more flexible processing of information and a re-evaluation of deeply held beliefs. In the context of EDs, this could translate to a restoration of healthy thought patterns regarding eating behavior and body image [Carhart-Harris & Friston, 2019].
• Emotional Processing: Psilocybin can facilitate profound emotional experiences, promoting openness, introspection, and an increased sense of connectedness. These experiences can lead to significant shifts in self-perception and values, which are vital for recovery from EDs [Peck et al., 2023].

Emerging Evidence: Clinical Trials and Case Studies

The UCSF Psilocybin for Anorexia Trial (Peck et al., 2023)

One of the most significant modern studies is a Phase 1, open-label feasibility study conducted at the University of California San Francisco, led by Dr. Stephanie Knatz Peck. Published in Nature Medicine in 2023, this trial involved 10 adult female participants with anorexia nervosa (AN) or partial remission AN (pAN) [Peck et al., 2023].

Participants received a single 25-mg dose of synthetic psilocybin (COMP360) alongside psychological support. The primary aim was to assess safety, tolerability, and feasibility. Key findings included:

• Safety and Tolerability: No serious adverse events were observed. All adverse events were mild and transient, with headache, nausea, and fatigue being the most common. No clinically significant changes were noted in vital signs, ECG, or suicidality [Peck et al., 2023].
• Psychopathology Reduction: At one-month follow-up, participants showed significant reductions in weight concerns (P = 0.036, Cohen’s d = 0.78) and shape concerns (P = 0.036, d = 0.78). Changes in eating concerns approached significance at three-month follow-up (P = 0.051, d = 0.71) [Peck et al., 2023].
• Clinically Significant Responses: Four participants (40% of the sample) demonstrated global Eating Disorder Examination (EDE) scores that decreased to within one standard deviation of community norms at three-month follow-up, indicating clinically significant improvements [Peck et al., 2023].
• Qualitative Perceptions: Participants reported the psilocybin experience as highly meaningful. 90% felt more positive about life, 80% considered it one of the top five most meaningful experiences of their lives, and 70% reported a shift in personal identity and overall quality of life. Notably, 90% felt that one dosing session was insufficient [Peck et al., 2023].

This study provides crucial preliminary data suggesting that psilocybin therapy is safe, tolerable, and acceptable for individuals with AN, paving the way for larger, controlled trials.

Psilocybin and Bulimia Nervosa / Binge Eating Disorder

Bulimia nervosa (BN) and binge eating disorder (BED) share neurobiological similarities with addiction, particularly involving dysregulation of the dopamine reward circuit and impaired impulse control [Koning & Brietzke, 2024]. Psilocybin’s ability to modulate the serotonin system and promote psychological flexibility may be beneficial in disrupting the compulsive binge-purge cycle or uncontrolled eating behaviors.

A 2022 case series from Johns Hopkins described three patients with bulimia who underwent psilocybin-assisted therapy. All three showed significant reductions in binge-purge frequency at the three-month follow-up, with two achieving full remission [Koning & Brietzke, 2024]. While these are preliminary findings, they align with psilocybin’s documented effects on other compulsive behaviors, such as substance use disorders [Koning & Brietzke, 2024].

Further, an open-label pilot study of psilocybin-assisted therapy for binge eating disorder, published in 2026, supports the feasibility and potential efficacy of this approach. This study found that psilocybin reduced activity in the default mode network (DMN) and increased global connectivity, which are neurobiological changes associated with improved cognitive flexibility and reduced compulsive behaviors [Dallery et al., 2026].

The Role of Mystical Experience and Psychological Breakthroughs

Across various studies on psilocybin-assisted therapy for mental health conditions, including eating disorders, the intensity of the mystical-type experience reported during psilocybin sessions consistently emerges as a strong predictor of positive outcomes [Koning & Brietzke, 2024]. Participants who describe experiences of unity, transcendence, and profound emotional release tend to show the greatest improvements. This suggests that the therapeutic mechanism of psilocybin extends beyond mere pharmacology; it involves profound psychological shifts facilitated by the unique experiential qualities of the psychedelic state.

These experiences can allow individuals to gain new perspectives on their entrenched patterns, observe their relationship with food and their body from a detached viewpoint, and access a sense of self-worth that their eating disorder may have obscured. This ability to "step outside" the eating disorder identity is a crucial psychological breakthrough that traditional therapies often struggle to achieve [Koning & Brietzke, 2024].

Safety Considerations and Future Directions

While the early evidence is promising, it is crucial to emphasize that psilocybin-assisted therapy for eating disorders is still in its nascent stages of research. Safety is paramount, especially given the medical complexities often associated with EDs. Individuals with severe underweight or electrolyte imbalances must be medically stabilized before considering psychedelic therapy [Koning & Brietzke, 2024]. Close medical and psychological monitoring is essential throughout the process.

Several clinical trials are currently underway, including Phase 2 trials investigating the efficacy and safety of psilocybin treatment in anorexia nervosa (e.g., NCT04661514, NCT04505189, NCT04052568) [ClinicalTrials.gov]. These larger, controlled studies will provide more definitive data on the efficacy, optimal dosing, and long-term outcomes of psilocybin-assisted therapy for EDs. The goal is not to replace existing treatments but to develop an adjunctive therapy that can significantly improve outcomes for a population desperately in need of more effective interventions.

The potential for psilocybin to enhance psychological flexibility, disrupt rigid thought patterns, and facilitate transformative experiences makes it a compelling area of research for eating disorders. As research progresses, it is hoped that this innovative approach, perhaps even supported by products like Happy Shrooomz functional mushroom gummies for general well-being, could offer a new path to recovery for many.

Frequently Asked Questions

Can psilocybin help anorexia nervosa?

Early clinical evidence is promising. A 2023 UCSF trial showed significant reductions in eating disorder psychopathology and improved body image after two psilocybin sessions. Larger trials are underway, and the initial findings suggest psilocybin-assisted therapy can be a safe and tolerable adjunctive treatment for AN [Peck et al., 2023].

Is psilocybin safe for people with eating disorders?

People with eating disorders who are medically unstable (e.g., severely underweight, significant electrolyte imbalances) should not undergo psilocybin therapy until medically stabilized. For those who are medically stable, the safety profile appears acceptable in controlled clinical settings, though close monitoring by trained professionals is essential [Koning & Brietzke, 2024].

Can microdosing help with eating disorder recovery?

There is limited formal clinical evidence specifically on microdosing for eating disorder recovery. However, anecdotal reports suggest that microdosing may help reduce obsessive thought patterns, anxiety, and cognitive rigidity that often perpetuate eating disorders. It is important to note that microdosing is not a replacement for structured therapeutic treatment and should be approached with caution and under professional guidance, if at all [Koning & Brietzke, 2024]. For more information on microdosing, you can explore resources on how to start microdosing psilocybin.

How does psilocybin affect the brain in the context of eating disorders?

Psilocybin primarily interacts with serotonin 2A receptors, leading to decreased activity in the default mode network (DMN) and increased connectivity across various brain regions. This promotes neuroplasticity and cognitive flexibility, helping to "loosen" rigid thought patterns and self-perception distortions common in eating disorders. These neurobiological changes facilitate new perspectives and emotional processing, which are crucial for therapeutic breakthroughs [Koning & Brietzke, 2024; Dallery et al., 2026].

What are the potential long-term benefits of psilocybin therapy for eating disorders?

While long-term data is still being gathered, the aim of psilocybin-assisted therapy is to facilitate enduring psychological shifts that can lead to sustained recovery. By addressing underlying cognitive rigidity, improving emotional regulation, and fostering a healthier sense of self, psilocybin may help individuals maintain positive changes in eating behaviors and body image, reducing relapse rates and improving overall quality of life. The transformative experiences reported by participants suggest potential for lasting positive impact [Peck et al., 2023].

References

• [Carhart-Harris & Friston, 2019] Carhart-Harris, R. L., & Friston, K. J. (2019). REBUS and the Anarchic Brain: Toward a Unified Framework for the Action of Psychedelics. Pharmacological Reviews, 71(3), 316-347. Link
• [ClinicalTrials.gov] U.S. National Library of Medicine. (Ongoing). ClinicalTrials.gov. Link
• [Dallery et al., 2026] Dallery, J., Miller, J. L., Boissoneault, J., & Harvey, L. (2026). An open-label pilot study of psilocybin-assisted therapy for binge eating disorder. Journal of Eating Disorders. (Forthcoming, cited in Koning & Brietzke, 2024). Link
• [Koning & Brietzke, 2024] Koning, E., & Brietzke, E. (2024). Psilocybin-assisted psychotherapy as a potential treatment for eating disorders: a narrative review of preliminary evidence. Trends in Psychiatry and Psychotherapy, 46, e20220597. Link
• [Peck et al., 2023] Peck, S. K., Shao, S., Gruen, T., Yang, K., Babakanian, A., Trim, J., ... & Kaye, W. H. (2023). Psilocybin therapy for females with anorexia nervosa: a phase 1, open-label feasibility study. Nature Medicine, 29(8), 1947-1953. Link
• [Rodan et al., 2021] Rodan, S. C., Aouad, P., McGregor, I. S., & Maguire, S. (2021). Psilocybin as a novel pharmacotherapy for treatment-refractory anorexia nervosa. OBM Neurobiology, 5(2), 102. Link