Psychedelic Research Recap: June 2026

June brought a wide spread of psychedelic research, from patient-facing trials and real-world cohorts to human neuroscience, qualitative work, and broader policy and methods papers. Clinical depression studies again dominated the month, but there were also important papers on safety, expectancy, context, and mechanisms across healthy volunteers and preclinical models.

Taken together, the set points to a field that is still expanding in two directions at once: closer to care, and deeper into the biology and lived experience of altered states.

Clinical Trials and Patient Care

This section gathers the papers closest to clinical use, from controlled trials and follow-up analyses to real-world cohorts and case series. The studies are grouped here because they ask the most direct questions about symptom change, safety, feasibility, and how these treatments might fit into care.

Johnson and colleagues reported a Phase 2a open-label clinical trial of inhaled mebufotenin (GH001) in women with postpartum depression. In this small study, symptoms improved rapidly, and remission was reported by day 8, with headache the most common adverse effect and no serious safety concerns noted. The paper is noteworthy for its focus on a peripartum population and for its exploratory breast milk measurements, which suggested rapid clearance after dosing.

Luoma and colleagues presented a randomised, open-label, wait-list-controlled trial of MDMA-assisted therapy for social anxiety disorder. The immediate treatment group improved more than the wait-list group on social anxiety and related functional measures, with no serious adverse events reported. The study also tracked psychotherapy process variables, which adds useful detail even though the sample was small and unblinded.

Weintraub and colleagues tested psilocybin-assisted cognitive behavioural therapy in a pilot trial for major depressive disorder. The programme was feasible, well accepted, and associated with sustained improvements in depression and functioning over three months, alongside positive feedback on the psychotherapy itself. It stands out as one of the clearer attempts this month to treat the psychotherapy component as an active part of the intervention rather than a background support.

Preiss and colleagues analysed real-world intranasal esketamine induction data from the enTRD registry. In routine outpatient care, depression scores fell substantially, suicidality improved, and tolerability was broadly acceptable, with few discontinuations. Because this was observational and single-centre, it cannot separate drug effects from care context, but it provides a useful contrast to the more tightly controlled trial literature.

Persico and colleagues used the REAL-ESK study to examine sex- and age-stratified antidepressant response to intranasal esketamine. Overall symptoms improved over three months, with men showing somewhat better outcomes than women by the end of follow-up, while safety looked similar across sexes. The analysis is exploratory, but it adds to the growing interest in who benefits most from esketamine in routine care.

Young and colleagues examined response trajectories in ESCAPE-TRD, a Phase IIIb study comparing esketamine nasal spray with quetiapine extended release. Most esketamine-treated patients improved continuously through Week 32, and early response was linked to better long-term outcomes. The item-level analyses suggest that symptom resolution was generally faster with esketamine than with quetiapine, although those comparisons were exploratory.

Kelly and colleagues reported a longer-term follow-up of psilocybin-assisted therapy in veterans with treatment-resistant depression. Anxiety, quality of life, functioning, and PTSD symptoms all improved, but most of the gains were no longer independent of concurrent depression change once the models were adjusted. The paper remains useful because it examines whether broader well-being outcomes co-vary with mood in this patient group.

Jungwirth and colleagues described real-world psilocybin therapy for treatment-resistant depression in routine clinical practice. Depressive symptoms fell with large effect sizes, but response and remission rates were lower than in many controlled trials, and additional dosing did not clearly add benefit at the group level. The study is valuable mainly because it shows what flexible, naturalistic psilocybin care looks like outside a trial setting.

Parks and colleagues studied at-home telehealth-supported subcutaneous ketamine in a very large real-world cohort. Symptoms of depression, anxiety, and PTSD all improved over six sessions, adverse events were uncommon, and serious complications related to injections were rare. The scale is striking, though the observational design means the findings are best read as signals of feasibility and real-world effectiveness rather than causal proof.

Fletcher and colleagues offered a qualitative account of ketamine-assisted psychotherapy for methamphetamine use disorder. Participants described a temporary reduction in emotional and cognitive reactivity that helped them engage with therapy, but behavioural change depended heavily on continued support and motivation. This is a useful reminder that subjective shifts during treatment do not automatically translate into durable change.

A qualitative study by Poppe and colleagues (n=17) explored why people with treatment-resistant depression chose to join clinical trials of 5-MeO-DMT or psilocybin and what they expected from them. Participants often saw trial entry as a last resort, and their expectations about symptom relief, the psychedelic experience and the trial setting could change after taking part.

Tabaac and colleagues described a case series of an integrative iboga microdosing protocol in people with post-concussive and hypoxic brain injury syndromes. All three cases improved, and two reported full symptom resolution at long-term follow-up, but the report is clearly exploratory and does not claim causation. It adds to the month’s small but growing literature on iboga-related interventions beyond addiction.

Onikashvili and colleagues reported a pilot randomised trial of ketamine for suicidal ideation in a paediatric emergency department. The study showed that such a trial is feasible, with acceptable recruitment, retention, blinding, and safety, but it was far too small to say anything firm about efficacy. Its main contribution is practical: it maps out what a larger emergency-department study would need to do differently.

Dagnino and colleagues used data from a double-blind randomised controlled trial to compare whole-brain responses to psilocybin and escitalopram in depression. The analysis found opposite changes in brain organisation after the two treatments, with psilocybin increasing non-equilibrium dynamics and escitalopram decreasing them. The paper is a secondary analysis, but it is one of the month’s clearest examples of a biomarker-style comparison between psychedelic and standard antidepressant treatment.

Frick and colleagues offered a retrospective Bayesian reanalysis of the same psilocybin-versus-escitalopram trial, focusing on sex differences in anxiety, anhedonia, and related outcomes. The signal was domain-specific rather than broad: women in the psilocybin arm did better on anxiety, while women in the escitalopram arm appeared to do better on anhedonia. The results are tentative, but they are useful because they push the field beyond average treatment effects towards more specific subgroup questions.

Dagnino and colleagues also reported a brief analysis of the brain network reconfiguration index after psilocybin or escitalopram in depression. Psilocybin increased reconfiguration under perturbation, whereas escitalopram decreased it, reinforcing the theme that these treatments push brain dynamics in different directions. The result is still preprint-level and should be treated as provisional, but it fits the broader mechanistic picture the group is building.

Haijen-Bongers and colleagues revisited repeated low-dose LSD in adults with ADHD in a randomised placebo-controlled study. The analysis found no broad benefits for attention, inhibition, or motivation, with the only notable signal appearing in one timing task. It is a cautious result, and the authors are right to frame it as a narrow neurocognitive effect rather than evidence of clinical benefit.

Human Mechanisms and Experience

These papers focus on healthy volunteers, surveys, interviews, and mechanism work that helps explain what psychedelic states feel like and how they may work. They are grouped together because they are mostly about acute or post-acute effects, context, prediction, and individual differences rather than direct patient benefit. The mix is especially useful this month because it shows how much of the field is still trying to pin down what matters during the experience itself.

Humbert-Droz and colleagues compared MDMA with and without a booster dose in healthy volunteers. The booster prolonged the subjective effects by about an hour without raising the peak, which suggests that the split-dose practice used in therapy may extend the session more than intensify it. Safety was broadly acceptable, although adverse effects were more common under MDMA than placebo and blinding was imperfect.

Klintefors and colleagues examined psilocybin's kinematic effect on manual dexterity in healthy participants. They found only small, short-lived changes, with no meaningful disruption to the basic coordination structure of hand movement. That is a helpful counterpoint to more speculative claims that psychedelics should broadly impair motor control.

de Cuba and colleagues reported a randomised, placebo-controlled trial of esketamine in healthy volunteers with brain-measures follow-up. They found sustained changes in cortical excitability and resting-state activity lasting up to seven days, especially after intravenous and higher-dose oral dosing. The paper is mechanistically detailed and points towards candidate biomarkers, even though it does not yet link those signals to clinical outcomes.

McCulloch and colleagues tested a wide set of fMRI entropy measures during psilocybin intoxication in healthy volunteers. Some metrics tracked subjective and pharmacokinetic effects, but many did not, and the measures were only weakly related to one another. The study is important because it cautions against treating all entropy-like measures as interchangeable.

Stein and colleagues showed that psychedelic context alone, without an active drug, can generate placebo-like altered states and nocebo-like side effects. Responsiveness to verbal suggestion and absorption were among the more informative trait predictors. It is a strong reminder that set and setting are not just background noise in psychedelic studies.

Calder and colleagues reported acute and post-acute neurobehavioural responses to LSD in healthy adults. They found improved motor learning the next day, lower perceived stress, and better cognitive flexibility one week later, alongside EEG and TMS changes. The behavioural effects are interesting, but the study also shows how hard it is to interpret post-acute findings when blinding is weak.

Jajcay and colleagues examined EEG microstate dynamics during psilocybin intoxication in healthy volunteers. Psilocybin sped up state switching and shortened microstate lifespans while preserving overall coverage, and those changes were linked to acute intensity and later psychological change. It is one of the month’s more compelling bridges between brain dynamics and subjective experience.

Egger and colleagues reported that buccal DMT plus harmine increased brain glucose metabolism in healthy volunteers. The rise was widespread, especially in higher-order networks, and was linked to harmine exposure rather than DMT levels or subjective intensity. The study adds a direct metabolic layer to the DMT and ayahuasca-style imaging literature.

Boardman and colleagues found that personality traits were moderately associated with sensory distortions during psychedelic experiences. Trait absorption was the clearest and most consistent predictor, although setting and dose mattered more overall. The paper is useful because it keeps the focus on measurable individual differences without overstating their importance.

Liang and colleagues examined the acute effects of esketamine on the EEG power spectrum and signal complexity in prolonged disorders of consciousness. They found clear neurophysiological changes, including lower delta power and higher beta, gamma, and complexity measures, but no behavioural improvement. The dissociation between brain change and behaviour is the key result here.

Walter and colleagues tested oral prolonged-release ketamine in two randomised clinical trials. The formulation caused far less dissociation and cardiovascular change than intranasal esketamine, but it did not meet the main depression endpoint at day 21, although there were signs of early symptom improvement. This is a careful, clinically relevant paper because it separates tolerability from efficacy rather than assuming the two will rise together.

Tarbi and colleagues developed a direct observation coding system for moments of awe narration during psilocybin-assisted therapy. They found that the system was feasible and reasonably reliable, especially when coders looked for vastness. This is a methods paper, but it is a useful one because it tries to make a subtle therapeutic experience observable and analysable.

Arns, Shinozuka, and Barsuglia reported a multisite retrospective analysis of ibogaine mortality, alongside an updated review of fatalities. Deaths were rare overall and were confined to opioid use disorder treatment in the clinical cohort, with none among non-SUD patients. The paper is likely to matter for policy discussions because it sharpens the distinction between indications rather than treating ibogaine risk as uniform.

Fotiadis and colleagues compared how brain-wave propagation changes across sleep, anaesthesia, and psychedelic states. They found that diminished states slowed and fragmented wave propagation, while psychedelic states sped it up and made it more evenly distributed. It is a broad comparative paper, but it helps place psychedelic brain dynamics within a wider consciousness framework.

Kirsch and colleagues explored attitudes and perceptions of psychedelic therapy among people with alcohol use disorder. Most participants knew something about the field and many were willing to join a trial, especially if they expected it to work. The interviews suggest that perceived promise matters more than simple awareness, which is a useful point for future recruitment and consent work.

A Tennessee-specific semi-Markov analysis evaluated medically monitored ibogaine for opioid use disorder. The model suggested lower costs, higher quality-adjusted life-years, and better survival over ten years, though the findings depend heavily on durability and programme-cost assumptions. It is a modelling paper rather than clinical evidence, but it gives a concrete economic frame for future implementation debates.

Galvan Rial and colleagues proposed a shared entropy-based axis of consciousness across pharmacological and clinical conditions. In their framing, propofol sits at the low-entropy end, while psychedelics and schizophrenia sit at the high-entropy end. As a brief conceptual paper, it mainly serves to connect several current strands in consciousness research.

Kringelbach and Deco argued that connectome harmonics, turbulence, and complex harmonics can be described by one shared operator. Using LSD-related perturbation data, they showed that changes in turbulence and harmonic energy moved together under the same structural perturbation. This is theory-heavy work, but it is clearly aimed at unifying several modelling traditions.

Carhart-Harris revisited the entropic brain hypothesis in a broad commentary. The piece argues that a wide range of findings, from psychedelics to sleep and disorders of consciousness, still fit the idea that higher entropy maps onto expanded consciousness and lower entropy onto reduced consciousness. It is a field-setting essay rather than a new result, but it remains influential in the interpretation of many of these studies.

Preclinical and Policy Signals

This final section completes the month by grouping early-stage, mechanistic, economic, and policy-adjacent papers. They are grouped here because they are either preclinical, highly modelled, or mainly informative for future design and regulation rather than direct patient care. The common thread is that each paper helps set the conditions under which the clinical studies above may eventually be judged.

West and colleagues reported that recent psychedelic exposure reduces top-down control of sensory processing in humans and mice. They link the effect to post-acute changes in feedback circuits and spine growth in prefrontal neurons, which makes the paper useful as a bridge between subjective experience and circuit-level plasticity. The translational design is a strength, even though the human arm is observational.

Seillier and colleagues found that 5-HT2B receptors were necessary for psilocybin's antidepressant-like effect in the rat forced swim test. Blocking that receptor abolished the behavioural benefit, but not the head-twitch response. The result is narrow, but it is an interesting reminder that psilocybin's therapeutic actions may not be reducible to 5-HT2A alone.

Pines and colleagues showed that psychedelics disrupt hierarchical cortical propagations in the default mode network across humans and mice. MDMA, psilocybin, and LSD all reduced the strength and bottom-up direction of activity flow, linking the findings to self-reported psychedelic experience. It is a concise cross-species signal that fits the month’s broader interest in network-level reorganisation.

Liao and colleagues used single-nucleus transcriptomics to map cell type-specific and time-dependent effects of psilocybin and ketamine in the mouse medial frontal cortex. The work shows biphasic psilocybin responses and pathway changes related to synaptic plasticity, metabolism, and glial function. As a resource paper, it is more about mechanism-building than immediate interpretation, but it adds a useful molecular layer to the month’s mechanistic literature.

Steinle and colleagues argued that hallucinogen-psychosis associations are confounded by baseline psychiatric history. Using claims data, they found that the apparent link between hallucinogen-related admissions and later psychosis largely disappeared after accounting for prior vulnerability. This is an important cautionary paper for both policy and clinical screening, even though it does not address psychedelics used in controlled therapeutic settings directly.