Set and setting predict psychopathology, wellbeing and meaningfulness of psychedelic experiences: a correlational study

Single-dose 1cp-LSD administration for canine anxiety: a pilot study

Anxiety affects 14-20% of dogs. Pharmacological treatments often fail. Psychedelics have shown to be useful for anxiety and depression in humans, but their veterinary use remains unexplored. We aimed to determine the effects of low-dose 1-cyclopropionyl-d-lysergic acid diethylamide (1cp-LSD) administered in a single dose to a dog, to observe the effect and establish the safety of the substance. The patient was a 13-year-old female dog, weighing 13 kg, mixed breed, and spayed. A total of 5 µg was administered orally, equivalent to 0.38 µg/kg. The animal has had a history of separation related behavioral problems throughout her life. To objectively assess the degree of anxiety in the dog, a validated scale was utilized. The trial was scheduled at the house where the animal lives. The owner was present throughout the experience. Informed consent was obtained prior to the assay. The trial began at 12:15 p.m. on January 10, 2024, lasting for 5 and a half hours. The response to anxiety-inducing stimuli was equally anxious during the first two hours. From that point onwards, a significant change in the animal's behavior was observed, with no signs/mild signs of anxiety. The trial concluded without any adverse effects on the animal. The patient did not show signs of having a psychedelic experience. This is the first time that a study of this nature has been conducted and reported in the canine species. 1cp-LSD proved to be safe and exerted the desired effect on the animal's behavior, significantly reducing the patient's anxiety.

Moving psychedelic-assisted therapies from promising research into routine clinical practice: Lessons from the field of implementation science

Psychedelics (e.g., 3,4-Methylenedioxymethamphetamine [MDMA], lysergic acid diethylamide [LSD], psilocybin) are molecules that have the potential to produce rapid therapeutic effects when paired with psychotherapy. Randomized clinical trials of psychedelic-assisted psychotherapy (PAT) have shown promising results for post-traumatic stress disorder (PTSD), depression, and substance use disorders. The U.S. Food and Drug Administration has acknowledged the promise of PAT, signaling potential approval of psilocybin-assisted therapy for depression by 2026. Given this timeline, implementation scientists must engage with PAT researchers, policymakers, and practitioners to think critically about bringing these promising new treatments into routine practice settings while maintaining quality and safety. This commentary aims to initiate a dialogue between implementation scientists and PAT researchers and practitioners on addressing these questions with a lens toward equity. Specifically, we discuss how the field of implementation science can support PAT stakeholders to accelerate the translational process from research into practice, focusing specifically on safety-net settings (i.e., Federally Qualified Health Centers and Veterans Affairs health systems) that serve historically marginalized populations. We use the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) Framework to illustrate five critical areas where implementation science can help move PAT from research into real-world practice. For each RE-AIM dimension, we highlight ways the field of implementation science can contribute tools (e.g., implementation strategies), methodologies (e.g., pragmatic hybrid implementation-effectiveness trials), and approaches (community-based participatory research) for establishing the safety, effectiveness, and accessibility of PAT for historically underserved communities.

Rapid and sustained reduction of treatment-resistant PTSD symptoms after intravenous ketamine in a real-world, psychedelic paradigm

BACKGROUND

Traditional treatments for post-traumatic stress disorder (PTSD) often show limited success with high dropout. Ketamine, an N-methyl-D-aspartate antagonist known for rapid antidepressant effects, has decreased PTSD symptoms in some studies but not in others. Administering ketamine in ways that parallel psychedelic-assisted treatments-including preparatory, integration, sensory immersion, and psychotherapy sessions-could decrease PTSD symptoms meaningfully.

METHODS

A retrospective sample of 117 screened outpatients with elevated PTSD Checklist for DSM-5 (PCL-5) scores received intravenous ketamine in supportive environments. The protocol included preparation, intention-setting, and integration sessions accompanying at least six administrations. Administration sessions included eye shades and evocative music paralleling typical psychedelic therapy trials.

RESULTS

Mean PCL scores decreased from 52.54 (SD = 12.01) to 28.78 (SD = 16.61), d = 1.64. Patients tolerated treatment well, with no serious adverse events. Covariates, including age, gender, days between PCL assessments, number of psychiatric medications, and suicidal ideation were not significant moderators; concomitant psychotherapy did reach significance, d = 0.51. Of the 117 patients' final PCL scores, 88 (75.21%) measures suggested clinically meaningful improvement and 72 (61.54%) suggested remission of PTSD symptoms.

CONCLUSION

Intravenous ketamine in supportive environments, with hallmarks of psychedelic therapy, preceded large reductions in PTSD symptoms. These results highlight ketamine's potential when delivered in this manner, suggesting environmental factors might account for some variation seen in previous work. Given the molecule's cost, minimal interaction with other psychiatric medications, and legal status, intravenous ketamine in a psychedelic paradigm may be a promising option for PTSD unresponsive to other treatments.

Psilocybin-enhanced fear extinction linked to bidirectional modulation of cortical ensembles

The serotonin 2 receptor (5HT2R) agonist psilocybin displays rapid and persistent therapeutic efficacy across neuropsychiatric disorders characterized by cognitive inflexibility. However, the impact of psilocybin on patterns of neural activity underlying sustained changes in behavioral flexibility has not been characterized. To test the hypothesis that psilocybin enhances behavioral flexibility by altering activity in cortical neural ensembles, we performed longitudinal single-cell calcium imaging in the retrosplenial cortex across a five-day trace fear learning and extinction assay. A single dose of psilocybin induced ensemble turnover between fear learning and extinction days while oppositely modulating activity in fear- and extinction- active neurons. The acute suppression of fear-active neurons and delayed recruitment of extinction-active neurons were predictive of psilocybin-enhanced fear extinction. A computational model revealed that acute inhibition of fear-active neurons by psilocybin is sufficient to explain its neural and behavioral effects days later. These results align with our hypothesis and introduce a new mechanism involving the suppression of fear-active populations in the retrosplenial cortex.