Ketamine and Psychedelics in Mental Health: Evidence, Promise, and the Path Forward
The landscape of mental health treatment is undergoing a profound transformation. After decades of prohibition, psychedelic compounds — including ketamine, psilocybin, and MDMA — are re-emerging as potential therapies for conditions that have long resisted conventional treatment. As a physician who has witnessed individual cases of tremendous improvement, I believe the responsible advancement of this field is vital. Yet the path forward requires careful navigation between therapeutic promise and the very real risks of misguided use.
The recent death of actor Matthew Perry, whose ketamine-related overdose made international headlines, serves as a sobering reminder: these are powerful substances that demand rigorous oversight, proper administration, and evidence-based protocols. The challenge before us is to ensure that publicized catastrophes don't create insurmountable obstacles for patients who could genuinely benefit from these treatments.
Where the Evidence is Strong
Ketamine for Depression
Ketamine stands apart as the only psychedelic-like substance currently legal for widespread medical use in the United States. The FDA approved esketamine (Spravato) in 2019 for treatment-resistant depression and for major depressive disorder with acute suicidal ideation, both in conjunction with an oral antidepressant.
The evidence base is substantial. Multiple clinical trials have demonstrated that ketamine produces rapid antidepressant effects, often within hours, in patients who have failed multiple conventional treatments. Unlike traditional antidepressants that require weeks to take effect, ketamine's rapid action offers critical relief, particularly for patients experiencing suicidal ideation.
However, there is an important caveat: ketamine's effects typically last from a few days to about two weeks, requiring repeated treatments to maintain benefit. This differs markedly from classical psychedelics, which may produce more durable effects.
Psilocybin for Major Depression
Psilocybin has emerged as perhaps the most promising classical psychedelic for depression. A landmark randomized clinical trial published in JAMA Psychiatry in 2021 found that psilocybin-assisted therapy produced substantial, rapid, and enduring antidepressant effects in patients with major depressive disorder. Remarkably, 71% of participants maintained a clinically significant response at four weeks post-treatment — a durability that exceeds ketamine.
A 2024 meta-analysis found that psilocybin showed the strongest therapeutic effect among psychedelics studied (effect size = -1.49), followed by ayahuasca (-1.34), MDMA (-0.83), and LSD (-0.65). The most common adverse event was headache, and nearly a third of studies reported no lasting adverse effects.
MDMA for PTSD
For post-traumatic stress disorder, MDMA-assisted psychotherapy has shown particularly compelling results. A 2026 systematic review found that four of six studies evaluating MDMA-assisted psychotherapy demonstrated statistically significant improvement in PTSD symptoms. The FDA granted MDMA breakthrough therapy status for PTSD, though it notably rejected a new drug application in 2024, highlighting the ongoing regulatory challenges.
For ketamine in PTSD, the evidence is more mixed: only three of seven studies showed statistically significant efficacy compared to controls.
Where Promise Exists But Evidence Remains Limited
Anxiety Disorders
While early data suggest psychedelics may benefit generalized anxiety disorder, the evidence base remains thin. Psilocybin received FDA breakthrough status for GAD, but large-scale trials are still needed. A 2022 study of at-home ketamine treatment found that 62.9% of patients showed 50% or greater improvement in anxiety symptoms, though this was an open-label effectiveness trial without a control group.
Substance Use Disorders
Preliminary evidence supports psychedelics for treating addiction to tobacco, alcohol, and other substances. The proposed mechanism involves disrupting entrenched patterns of thought and behavior while promoting psychological flexibility and insight. However, rigorous controlled trials are needed before these applications can be considered evidence-based.
Other Conditions
Small studies suggest potential benefits for obsessive-compulsive disorder, eating disorders, and end-of-life psychological distress in patients with terminal illness. These remain areas of active investigation rather than established indications.
Legal Status and Access in the United States
The legal landscape is complex and rapidly evolving.
At the federal level, psilocybin, LSD, MDMA, and DMT remain Schedule I substances under the Controlled Substances Act, classified as having no currently accepted medical use. Ketamine is Schedule III, allowing medical use. Esketamine (Spravato) is FDA-approved for specific indications and must be administered in certified healthcare settings with monitoring.
Since Denver became the first U.S. city to decriminalize psilocybin in May 2019, numerous jurisdictions have followed. Oregon became the first state to both decriminalize psilocybin and legalize it for therapeutic use in 2020, with licensed facilities beginning operations in 2023. Colorado, several California cities, and other jurisdictions have enacted similar measures.
Psychedelics can also be legally administered in FDA-approved clinical trials. Academic centers at Johns Hopkins, UCSF, Mount Sinai, and other institutions are conducting ongoing research.
Internationally, Australia became the first country to approve psychiatrist-prescribed psilocybin for treatment-resistant depression and MDMA for PTSD in 2023. Switzerland allows limited compassionate use. Canada and Jamaica have moved toward decriminalization.
The Critical Distinction: Supervised vs. Unsupervised Use
In-Person Guided Therapy
All published clinical trials showing positive outcomes for psilocybin and MDMA have involved clinician-assisted intervention with extensive psychological support. The typical protocol includes preparatory sessions to establish therapeutic alliance and set intentions, supervised dosing sessions lasting 6 to 8 hours with trained therapists present, and integration sessions to process the experience and consolidate insights. This model requires approximately 11 hours of direct therapeutic contact per patient for psilocybin treatment.
Supervised At-Home Use
A newer model involves at-home ketamine treatment with remote monitoring via telehealth. A large 2022 prospective study of 1,247 patients receiving at-home sublingual ketamine with psychosocial support found response rates of 62.8% for depression and 62.9% for anxiety, comparable to clinic-administered treatment. Only four patients left treatment early due to side effects or adverse events.
However, this model remains controversial. While it addresses access barriers and proved particularly valuable during COVID-19, it lacks the intensive in-person support that characterizes classical psychedelic therapy protocols.
Unsupervised Self-Treatment
This is where risk escalates dramatically. Individuals obtaining ketamine or other psychedelics online for self-treatment face multiple dangers:
Substance purity and dosing — illicit substances may be contaminated, mislabeled, or contain unexpected compounds
Medical screening — psychedelics can trigger psychosis in vulnerable individuals and are contraindicated in certain medical conditions
Lack of psychological support — the psychedelic experience can be psychologically destabilizing without proper preparation and integration
Polydrug use — a 2021 Australian study found that 95.5% of ketamine-related deaths involved other drugs, with opioids present in 59.1% of cases
Escalating use — while therapeutic ketamine use hasn't been associated with dependence, recreational use can escalate to dependency with dose-dependent cognitive impairment, urinary tract damage, and gastrointestinal problems
A 2025 analysis found ketamine-related poisonings in the U.S. increased from 205 in 2019 to 414 in 2023, with suspected suicide attempts doubling. Deaths following illicit ketamine use in England, Wales, and Northern Ireland increased more than 10-fold from 2014 to 2024.
Critically, a 2023 systematic review found no cases of overdose or death related to ketamine use as an antidepressant in therapeutic settings — underscoring the stark difference between medical and unsupervised use.
The Matthew Perry Tragedy and Its Implications
The death of Matthew Perry from acute effects of ketamine in October 2023 brought unprecedented public attention to ketamine's risks. While details of his case involve alleged improper prescribing and administration, it highlights several critical issues: the danger of unsupervised access, the risks of combining ketamine with other central nervous system depressants, and the need for proper protocols including careful patient selection, appropriate dosing, monitoring, and integration support.
The tragedy risks creating a backlash that could impede access for patients who might genuinely benefit — making the development of clear, evidence-based guidelines and regulatory frameworks even more urgent.
Barriers to Advancing the Field
The Schedule I classification of classical psychedelics creates substantial research barriers. The FDA's 2024 rejection of MDMA for PTSD, despite promising trial data, illustrates the high evidentiary bar these treatments must clear.
Psychedelic research also faces unique methodological difficulties. The intense subjective effects make it obvious to participants whether they received active drug or placebo, potentially inflating results through expectancy effects. There is no consensus on optimal psychotherapy protocols, dosing regimens, or patient selection criteria. Most trials have followed patients for weeks to months, not years.
A fundamental question also remains unresolved: is the psychedelic experience itself therapeutic, or are these compounds working through purely pharmacological mechanisms? Recent research suggests both may be true — studies show that the intensity of mystical-type experiences correlates with therapeutic outcomes, yet psychedelics also promote neuroplasticity through BDNF-TrkB signaling and modulate brain networks in ways that may be therapeutic independent of subjective experience.
The Path Forward
The field stands at a critical juncture. The therapeutic potential is real — I've seen it in individual patients whose lives have been transformed. But realizing this potential while ensuring patient safety requires rigorous research, standardized protocols, appropriate regulation, professional training, public education, and a commitment to equitable access.
The Matthew Perry tragedy and similar cases must not derail progress for patients who have exhausted conventional options. But neither should enthusiasm outpace evidence. The responsible advancement of psychedelic medicine requires maintaining this difficult balance — embracing the promise while rigorously addressing the risks.
For patients suffering from treatment-resistant depression, PTSD, and other debilitating conditions, these therapies may offer hope where little existed before. Our obligation is to ensure that hope is grounded in science, delivered with appropriate safeguards, and accessible to those who need it most.
References
Davis AK, Barrett FS, May DG, et al. Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder: A Randomized Clinical Trial. JAMA Psychiatry. 2021.
Yao Y, Guo D, Lu TS, et al. Efficacy and Safety of Psychedelics for the Treatment of Mental Disorders: A Systematic Review and Meta-Analysis. Psychiatry Research. 2024.
Thomas JE, Dellarole A, Caballero J. Efficacy and Risks of Psychedelics in Treatment of Posttraumatic Stress Disorder: A Systematic Review. American Journal of Health-System Pharmacy. 2026.
Hull TD, Malgaroli M, Gazzaley A, et al. At-Home, Sublingual Ketamine Telehealth Is a Safe and Effective Treatment for Moderate to Severe Anxiety and Depression. Journal of Affective Disorders. 2022.
Palamar JJ, Jewell JS, El-Shahawy O, Black JC. Trends in Poisonings Involving Ketamine in the United States, 2019-2023. Drug and Alcohol Dependence. 2025.
Darke S, Duflou J, Farrell M, Peacock A, Lappin J. Characteristics and Circumstances of Death Related to the Self-Administration of Ketamine. Addiction. 2021.
Pullen J, Corkery JM, McKnight R, Copeland CS. Deaths Following Illicit Ketamine Use in England, Wales and Northern Ireland 1999-2024. Journal of Psychopharmacology. 2025.
Siegel JS, Daily JE, Perry DA, Nicol GE. Psychedelic Drug Legislative Reform and Legalization in the US. JAMA Psychiatry. 2023.
Jacobs E, Zahid Z, Hinkle J, Nayak S, Yaden DB. Psychedelic Medicine: Mechanisms, Evidence, and Translation to Practice. BMJ. 2026.
Veraart JKE, Schimmers N, Breeksema JJ, et al. Ketamine-Assisted Psychotherapies for Mental Disorders: A Historical Overview and Systematic Review. Clinical Psychology Review. 2026.
Dr. Schraga is a concierge physician at Crescendo MD in Portola Valley, California, specializing in preventive and longevity medicine for executives and families in Silicon Valley.
