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Erwin Krediet

Department of Psychiatry, Leiden University Medical Center, Leiden, The Netherlands.

7 papers in the library · 702 citations · publishing 2019-2025

Papers

Reviewing the Potential of Psychedelics for the Treatment of PTSD

The International Journal of Neuropsychopharmacology March 12, 2020 Erwin Krediet, Tijmen Bostoen, Joost J. Breeksema et al. 262 citations

Posttraumatic stress disorder (PTSD) often remains chronic after psychotherapy, and few effective medications exist. A promising new approach involves psychedelic drugs. This review discusses four compound types: MDMA, ketamine, classical psychedelics (psilocybin, LSD), and cannabinoids. It describes each compound's therapeutic rationale, administration setting, and current evidence for treating PTSD. Each offers unique qualities, from rapidly targeting symptoms to facilitating psychotherapy. The review outlines questions for future research.

Psychedelic Treatments for Psychiatric Disorders: A Systematic Review and Thematic Synthesis of Patient Experiences in Qualitative Studies

CNS Drugs August 17, 2020 Joost J Breeksema, Alistair R Niemeijer, Erwin Krediet et al. 217 citations

This review argues that qualitative research on psychedelic treatments can reveal unique features of different substances and uncover implications for treating specific psychiatric disorders that quantitative methods might miss. By examining subjective experiences, such studies can help tailor therapies to particular conditions and substances, offering insights into how psilocybin, LSD, or other compounds produce distinct psychological effects. The authors suggest that incorporating qualitative findings into clinical practice could enhance treatment precision and patient outcomes, highlighting the value of exploring personal narratives and emotional processes in psychedelic therapy.

Safety, tolerability, pharmacokinetics, and pharmacodynamics of low dose lysergic acid diethylamide (LSD) in healthy older volunteers

Psychopharmacology December 18, 2019 Neiloufar Family, Émeline L. Maillet, Luke T. J. Williams et al. 142 citations

Repeated low doses of LSD are safe and well tolerated in older adults. In a double-blind, placebo-controlled trial, 48 healthy volunteers aged around 63 received either 5, 10, or 20 micrograms of LSD or a placebo every four days for three weeks. LSD was undetectable in the blood at the 5 microgram dose, while peak levels for higher doses occurred within 30 minutes. Adverse events were no more frequent than with placebo, and tests of cognition, balance, and proprioception showed no impairment. These results support further clinical development of low-dose LSD for treating or preventing Alzheimer's disease.

Patient perspectives and experiences with psilocybin treatment for treatment-resistant depression: a qualitative study

Scientific Reports February 5, 2024 Alistair Niemeijer, Erwin Krediet, Jeanine Kamphuis et al. 50 citations

Patients with treatment-resistant depression who received psilocybin in a clinical trial described challenges with trust-building and expectation management, the need to navigate intense experiences often guided by music, and a desire for a more comprehensive treatment including multiple psilocybin sessions and sustained therapy. Distrust in mental healthcare generally, but trust in study therapists, was a key subtheme. The findings suggest that optimizing psilocybin treatment for this population requires individualized preparation, investment in trust-building, additional sessions, and access to ongoing psychotherapy with trusted therapists.

Safety, tolerability, pharmacokinetics, and subjective effects of 50, 75, and 100 µg LSD in healthy participants within a novel intervention paradigm: A proof-of-concept study

Journal of Psychopharmacology March 1, 2022 Neiloufar Family, Peter S. Hendricks, Luke T. J. Williams et al. 23 citations

LSD doses of 50, 75, and 100 micrograms are tolerable and safe in healthy adults when administered in a novel group-based intervention paradigm with one attendant per participant. Thirty-two adults (mean age 28.8 years) received LSD or placebo across open-label and double-blind designs. No serious adverse events occurred; 28% of participants reported at least one mild expected adverse event and one moderate event. Peak blood plasma levels appeared 1.2 to 2 hours after administration, with an apparent half-life of 2.8 to 4.3 hours. LSD produced greater subjective effects than placebo, including mystical-type experiences. Further research is needed in clinical populations.

Assessing the Attitudes of Dutch Mental Health Care Professionals Toward Psychedelic-Assisted Psychotherapy: A Cross-Sectional Exploratory Study

Journal of Psychoactive Drugs June 23, 2025 Annika Wirsching, Erwin Krediet, Martijn H.b. Koolen et al. 4 citations

Dutch mental health professionals hold generally positive attitudes toward psychedelic-assisted psychotherapy (PAP) for conditions like PTSD and major depression, according to a survey of 198 clinicians. Positive attitudes were associated with clinicians' own prior use of MDMA or psilocybin. Respondents considered psychiatrists and licensed psychologists the most suitable professionals to administer PAP, expressed concerns about maintaining therapeutic connection during patients' altered states, and preferred that PAP be delivered in specialized hospital-based facilities. The findings point to implementation needs, including targeted training and clear clinical guidelines.

A model training curriculum for psychedelic, psycholytic, and entactogen-assisted psychotherapy.

Journal of psychopharmacology (Oxford, England) June 10, 2025 Torsten Passie, Anja Loizaga-Velder, Alicia Danforth et al. 4 citations

A consensus-based model curriculum for education and training in substance-assisted psychotherapy (SAP) covers theoretical topics and practical components including apprenticeship observation, ongoing clinical supervision, and self-experience for trainees. The model, developed by authors with extensive SAP experience, also addresses peer and conventional supervision, respect for intercultural differences, and teachings about indigenous use of related substances. It is largely adapted to western industrialized countries with established graduate-level psychotherapy training. The curriculum may be valuable for psychedelic researchers, those training therapists for research studies, and those preparing for clinical work outside research settings.