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Matthew W. Johnson

Johns Hopkins Medicine

52 papers in the library · 10,370 citations · publishing 2010-2026

Papers

Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities

The International Journal of Neuropsychopharmacology May 10, 2021 Natalie Gukasyan, David B. Yaden, Matthew W. Johnson et al. 56 citations

Psychedelic substances produce unusual changes in conscious experience, leading some to propose they offer unique insights into consciousness. However, psychedelics are unlikely to provide information relevant to the "hard problem of consciousness," which involves explaining how first-person experience emerges. Instead, they bear on multiple "easy problems of consciousness," involving relations between subjectivity, brain function, and behavior. This review discusses common meanings of "consciousness" regarding psychedelics and considers models of their effects on the brain linked to explanatory claims about consciousness. It calls for epistemic humility about psychedelic research's potential to explain the hard problem while noting ways psychedelics may advance study of specific aspects of consciousness.

DOI: 10.1093/ijnp/pyab026 Full text Consciousness Neuroscience Cognitive psychology

The Acute Effects of the Atypical Dissociative Hallucinogen Salvinorin A on Functional Connectivity in the Human Brain

Scientific Reports October 2, 2020 Manoj K. Doss, Darrick G. May, Matthew W. Johnson et al. 52 citations

Salvinorin A, a κ-opioid receptor agonist and dissociative hallucinogen found in Salvia divinorum, alters human brain functional connectivity in ways similar to other hallucinogens. In a placebo-controlled, within-subject fMRI study, inhaled Salvinorin A tended to decrease functional connectivity within brain networks while increasing connectivity between networks, most notably attenuating the default mode network during peak effects. It reduced brainwide dynamic functional connectivity but increased brainwide entropic functional connectivity, though only the reduction survived statistical correction. Connectome-based classification models trained on dynamic connectivity accurately identified Salvinorin A scans, especially when using default mode network interactions. These findings suggest shared neural mechanisms across hallucinogen types.

DOI: 10.1038/s41598-020-73216-8 Full text Default mode network Ayahuasca Hallucinogen Dissociative +6

Psychedelic Identity Shift: A Critical Approach to Set And Setting

Kennedy Institute of Ethics journal December 1, 2022 Neşe Devenot, Aidan Seale‐feldman, Elyse Smith et al. 50 citations

Psychedelic medicine relies on set and setting, but the specific therapeutic frameworks used alongside the drugs are rarely studied. Analyzing a treatment manual and post-session reports from a pilot psilocybin-assisted smoking cessation study, this article shows how therapeutic frameworks interact with psilocybin to rapidly reshape participants' identity and sense of self. Multiple domains of identity shift were identified that appear to serve as mechanisms for quitting smoking, each present in the manualized treatment. As psychedelic medicine becomes mainstream, consensual, evidence-based approaches to identity shift that respect patient autonomy and encourage empowerment should become key in psychedelic bioethics.

DOI: 10.1353/ken.2022.0022 Psilocybin Psychotherapist Autonomy Psychology +9

On the Varieties of Conscious Experiences: Altered Beliefs Under Psychedelics (ALBUS)

November 30, 2020 Adam Safron, Arthur Juliani, Nicco Reggente et al. 44 citations preprint

Psychedelics may both relax and strengthen beliefs depending on the dose and brain system involved. The REBUS model holds that 5-HT2a receptor activation relaxes prior expectations, enabling new perspectives. This paper proposes that at very high levels of 5-HT2a agonism, opposite effects can occur—termed SEBUS—where synchronous neural activity strengthens beliefs, enhancing meaning-making, hallucinations, and even delusional thinking. The ALBUS framework integrates these opposing effects across the dose-response curve, suggesting psychedelic experiences resemble waking dream states with varying lucidity. The authors provide neurophenomenological models of perceptual synthesis, dreaming, and episodic memory to support this view.

DOI: 10.31234/osf.io/zqh4b Full text Psychology

Classic Psychedelics in Addiction Treatment: The Case for Psilocybin in Tobacco Smoking Cessation

Current topics in behavioral neurosciences January 1, 2022 Matthew W. Johnson 31 citations

Classic psychedelics (5-HT2A receptor agonists) show promise for treating addictions, including tobacco use disorder. Historical research from the 1950s–1970s linked these substances to addiction recovery across various drugs. Anthropological reports and epidemiological studies also support anti-addiction efficacy. Modern studies using psilocybin for alcohol and tobacco use disorders report high success rates. The general anti-addiction effect across different addictive drugs suggests psychedelic therapy amplifies psychotherapeutic processes, leading to lasting positive behavior change. Future research should explore treatments for other substance use disorders and additional psychedelics. Given societal costs, public funding for this research is critical.

DOI: 10.1007/7854_2022_327 Addiction Psilocybin Mescaline Cannabis +5

Naltrexone but Not Ketanserin Antagonizes the Subjective, Cardiovascular, and Neuroendocrine Effects of Salvinorin-A in Humans

The International Journal of Neuropsychopharmacology February 12, 2016 Marta Valle, Montserrat Puntes, Jimena Coimbra et al. 31 citations

Salvinorin-A, a terpene from the plant Salvia divinorum, induces an intense but short-lasting altered state of awareness similar to classical psychedelics, but it acts on kappa-opioid receptors rather than serotonin-2A receptors. In a double-blind, placebo-controlled study with 24 healthy volunteers experienced with psychedelics, inhalation of 1 mg of vaporized salvinorin-A severely reduced external sensory perception, caused intense visual and auditory modifications, and increased systolic blood pressure, cortisol, and prolactin. These effects were effectively blocked by the opioid antagonist naltrexone (50 mg orally) but not by the serotonin-2A antagonist ketanserin (40 mg orally), confirming that salvinorin-A's mechanism involves kappa-opioid receptor agonism and not serotonin-2A agonism.

DOI: 10.1093/ijnp/pyw016 Full text Serotonin Ketanserin Naltrexone Hallucinogen +7

Predicting changes in substance use following psychedelic experiences: natural language processing of psychedelic session narratives

The American Journal of Drug and Alcohol Abuse June 5, 2021 David J. Cox, Albert Garcia-Romeu, Matthew W. Johnson 29 citations

People who quit or reduced using alcohol, cannabis, opioids, or stimulants after a psychedelic experience provided written narratives of that experience. Natural language processing extracted topic models from the narratives, and three machine learning algorithms predicted long-term drug reduction outcomes with about 65% accuracy. The quantitative descriptions of the experiences differed depending on which drug class was quit and whether the reduction was sustained. The findings suggest that analyzing written reports of psychedelic experiences with machine learning could help predict who will benefit from psychedelic therapy for substance use.

DOI: 10.1080/00952990.2021.1910830 Cannabis Narrative Harm reduction Clinical psychology +1

Effects of Psilocybin on Religious and Spiritual Attitudes and Behaviors in Clergy from Various Major World Religions

Psychedelic Medicine May 16, 2025 Roland R. Griffiths, William A. Richards, Robert L. Jesse et al. 14 citations

In clergy from various world religions who had never used psychedelics, two supported psilocybin sessions (20 mg/70 kg, then 20 or 30 mg/70 kg) led to sustained positive changes in religious practices, attitudes about their religion, and effectiveness as a religious leader, as well as in non-religious attitudes, moods, and behavior, compared with a waitlist control group. At 16‑month follow‑up, 96% rated at least one experience among the top five most spiritually significant of their lives, 42% rated it the single most profound, and 79% reported positive effects on daily sense of the sacred. No serious adverse events occurred, though 46% rated an experience among the top five most psychologically challenging of their lives.

DOI: 10.1089/psymed.2023.0044 Psilocybin Hallucinogen Social psychology Psychotherapist +1

Psychiatry might need some psychedelic therapy

International Review of Psychiatry July 4, 2018 Matthew W. Johnson 12 citations

Psychedelic drugs have shown promise for treating psychiatric disorders in both historical and modern studies, yet their medical use remains controversial. The controversies have often hindered research and clinical application despite potential benefits. The text discusses these ongoing debates without presenting new empirical data.

DOI: 10.1080/09540261.2018.1509544 Psychology Psychotherapist Hallucinogen Psychiatry +1

Shame, Guilt and Psychedelic Experience: Results from a Prospective, Longitudinal Survey of Real-World Psilocybin Use

Journal of Psychoactive Drugs February 7, 2025 Amy Lehrner, Heather Jackson, David S. Mathai et al. 11 citations

Among 679 adults using psilocybin in naturalistic settings, 68.2% reported acute feelings of shame or guilt during the experience, which were difficult to predict. The ability to constructively work through these feelings predicted wellbeing 2-4 weeks later. On average, psilocybin produced a small but significant decrease in trait shame maintained 2-3 months after use (Cohen's dz = 0.37), though trait shame increased in 29.8% of participants. The activation of self-conscious emotions with psychedelics warrants further attention as a challenging experience subcategory relevant to psychological outcomes, potentially creating a unique learning condition for shame-related memory reconsolidation.

DOI: 10.1080/02791072.2025.2461997 Psilocybin Shame Hallucinogen Clinical psychology +1

Beliefs and Perceived Barriers Regarding Psychedelic-assisted Therapy in a Pilot Study of Service Members and Veterans With a History of Traumatic Brain Injury

Military Medicine December 24, 2022 Joshua C. Gray, Mikela A. Murphy, Sierra Carter et al. 10 citations

Service members and veterans with traumatic brain injury and co-occurring symptoms initially held neutral views of psychedelic drugs and psychedelic-assisted therapies (PAT). After a brief psychoeducation session, their views of psychedelic drugs and interest in PAT became significantly more positive. Most participants supported making PAT available in medical settings if proven beneficial and would support a loved one engaging in PAT. The most common health concerns were long-term effects (43%), fear of losing one's mind (33%), fear of personality changes (33%), and fear of traumatic brain injury complications (24%). Logistical barriers included time, transportation, finances, work, and childcare, though 48% reported no barriers.

DOI: 10.1093/milmed/usac400 Full text Service member Military medicine Navy Military service +5

A Field-Wide Review and Analysis of Study Materials Used in Psilocybin Trials: Assessment of Two Decades of Research

Psychedelic Medicine January 20, 2025 Marianna Graziosi, Gabrielle Agin-Liebes, Mary P Cosimano et al. 9 citations

Psilocybin and other serotonergic psychedelics are used in research settings with safety measures including controlled environments, staff presence, screening, and psychoeducation. An analysis of study materials from psilocybin trials over the past two decades found that psychoeducation documents varied but commonly emphasized biological and physical safety, psychological safety and well-being, aspects of setting, and the potential for expectancies. The materials prioritized biological and psychological safety across all sites. The authors also identified elements unrelated to safety that may contribute to participant expectancies and suggest these extrapharmacological factors be studied systematically to maximize safety while minimizing extraneous expectancies.

DOI: 10.1089/psymed.2024.0019 Psilocybin Field mathematics Psychology

Psychedelics and substance use disorder treatment.

International review of neurobiology January 1, 2025 Caitlin M. DuPont, Matthew W. Johnson 6 citations

Classic psychedelics, including LSD, psilocybin, and ayahuasca, show benefits for reducing drinking and achieving abstinence in alcohol use disorder, with small clinical trials also showing promising initial results for tobacco and opioid use disorders. No trials have yet been conducted for stimulant or cannabis use disorders. Most evidence comes from naturalistic observational studies or correlational survey data, which, combined with clinical trials, suggest potential broad transdiagnostic efficacy across multiple addictive drugs. These effects likely stem from biological improvements in brain areas involved in reward and emotional processing, reducing relapse risk, and psychological insights that reinforce personal motivations for sobriety. More work is needed to characterize benefits and limitations.

DOI: 10.1016/bs.irn.2025.03.005 Full text Alcohol use disorder Ayahuasca LSD Psilocybin +10

Long-term follow-up of psilocybin-facilitated smoking cessation: Abstinence outcomes and qualitative analysis of participant accounts

Drug and Alcohol Dependence November 1, 2015 Albert Garcia‐romeu, Tehseen Noorani, Roland R. Griffiths et al. 6 citations

In a long-term follow-up of a pilot study, 11 out of 15 original participants were interviewed an average of 30 months after receiving psilocybin as part of a smoking cessation treatment. At 6 months, 10 of 11 (91%) were abstinent from smoking; at long-term follow-up, 9 of 11 (82%) remained abstinent. Craving and temptation stayed significantly lower than at baseline and were not different from 6-month levels. Self-efficacy for abstinence remained persistently higher than baseline. Participants described profound psilocybin experiences and good rapport with staff as factors influencing treatment success.

DOI: 10.1016/j.drugalcdep.2015.07.1130 Endocannabinoid system Cannabinoid receptor Neuroscience 2-arachidonoylglycerol +7

Psilocybin in the Treatment of Cocaine Use Disorder

JAMA Network Open May 7, 2026 Peter S. Hendricks, Sara Lappan, Richard C. Shelton et al. 4 citations

A single 25 mg dose of psilocybin, combined with psychotherapy, led to a higher percentage of cocaine-abstinent days, a greater likelihood of complete abstinence, and a longer time before the first cocaine lapse over 180 days compared with an active placebo (100 mg diphenhydramine) in a randomized, quadruple-blind trial. Among 40 participants with cocaine use disorder, 33 were men, 33 were Black, and most had low income. Psilocybin appeared safe, with no serious adverse events, and may offer a treatment for cocaine use disorder in underrepresented populations.

DOI: 10.1001/jamanetworkopen.2026.11029 Psilocybin Abstinence Cocaine dependence Cocaine use +9

Adverse reactions among psychedelic users: Norwegian validation of the Challenging Experience Questionnaire

Journal of Psychiatric Research May 26, 2025 Bjørn Holmøy, Tor-Morten Kvam, Kristoffer Andreas Aamodt Andersen et al. 3 citations

A Norwegian translation of the Challenging Experience Questionnaire (CEQ) shows strong reliability and validity for assessing adverse psychedelic experiences. An online survey of 729 Norwegian recreational psychedelic users, mostly male (73%) and aged 26–35 (41%), with 90% having used LSD or psilocybin, confirmed the original 7-factor structure. The translated CEQ demonstrated excellent internal consistency (alpha = 0.94) and good overall model fit. The tool also showed factorial invariance across gender and psychiatric status, and convergent validity through relationships between reported difficulty and factors like fear, grief, insanity, and death. This provides Norwegian researchers with a culturally adapted, psychometrically valid tool for evaluating complex adverse reactions to psychedelic use.

DOI: 10.1016/j.jpsychires.2025.05.062 Norwegian Clinical psychology Psychiatry

Psychedelics and Health Behavior Change - Journal of Psychopharmacology (in press)

March 24, 2021 Pedro J. Teixeira, Matthew W. Johnson, Christopher Timmermann et al. 1 citation preprint

Unhealthy behaviors like poor diet, inactivity, and smoking are major contributors to cancer, diabetes, and cardiovascular disease, causing substantial suffering and public health costs. Interventions to promote healthy behaviors increasingly draw on psychobiological models. This article explores the potential of psilocybin, a psychedelic with low toxicity and no addictive properties, to assist positive lifestyle change. Psilocybin has shown favorable effects in patients with depression, anxiety, and substance misuse, conditions marked by rigid behavioral patterns. The authors describe proposed mechanisms and research findings linking psychedelics to health behavior change, noting that therapeutic models combining psychedelic experiences with methods like Cognitive Behavior Therapy and Motivational Interviewing are already being tested for addiction and eating disorders. They suggest this research may extend to promoting diet, exercise, nature exposure, and mindfulness.

DOI: 10.31234/osf.io/8vks6 Full text Anxiety Addiction Psilocybin Mindfulness +10