Psychedelics
June 28, 2026
Joost J. Breeksema, Ulf Bremberg, Jens H van Dalfsen et al.
The research, understanding, and implementation of psychedelic therapies is characterised by a layered complexity that arises from the dynamic interactions between pharmacological and extra-pharmacological factors, and the embeddedness of psychedelics within broader societal, legal, and regulatory systems ill-equipped to accommodate them. This complexity is compounded by an epistemic...
Clinical Psychology Review
February 2, 2026
Jolien K E Veraart, Nina Schimmers, Joost J. Breeksema et al.
4 citations
Ketamine-assisted psychotherapy (KAP) is considered a promising treatment strategy in psychiatric disorders, combining psychotherapeutic interventions with the rapid-acting pharmacological effects of ketamine towards enhancing outcomes. Although KAP has been practiced for many years across different diagnoses, evidence regarding optimal treatment methods and working mechanisms remains limited...
Nature Medicine
June 3, 2025
Chloé Pronovost-Morgan, Kyle T. Greenway, Leor Roseman et al.
26 citations
Psychedelic substances exhibit complex interactions with the 'set and setting' of use, that is, the mental state of the user and the environment in which a psychedelic experience takes place. Despite these contextual variables' known importance, psychedelic research has lacked methodological rigor in reporting extra-pharmacological factors. This study aimed to generate consensus-based...
Psychiatr Res Clin Pract
February 11, 2025
Jules Evans, Marc Aixalà, Brian T Anderson et al.
18 citations
Objective: This article outlines recommendations from 30 psychedelic researchers on how to create a better psychedelic safety net. Methods: A survey of 30 psychedelic researchers asked them to identify key critical research gaps around psychedelic harm and safety. Results: The critical research gaps identified by the authors included defining the main types of psychedelic harm, the predictors...
The lancet. Psychiatry
2025
Carolina Seybert, Nina Schimmers, Lucio Silva et al.
26 citations
Although studies of psychedelic-assisted psychotherapy are accumulating, there is no consensus regarding best practice of the psychotherapeutic component. In this systematic review, we summarised the quality of reporting on psychological interventions in research about psychedelic treatments. The design followed PRISMA guidelines and was preregistered in PROSPERO (CRD42022319221). We searched...
International review of neurobiology
2025
Stephan Tap, Tijmen Bostoen, Joost J. Breeksema et al.
4 citations
Patients with a life-threatening disease (LTD) sometimes suffer from end-of-life distress (EOLD) which refers to the physical, psychological, emotional, and spiritual suffering related to chronic illness and the possibility of death. Palliative care interventions seek to improve the quality of life of patients with EOLD and their significant others. Currently, a range of psychological and...
International review of neurobiology
2025
Tijmen Bostoen, Stephan Tap, Joost J. Breeksema et al.
1 citation
Post-Traumatic Stress Disorder (PTSD) is a severe psychiatric condition that develops after exposure to trauma such as combat, natural disasters, or assault. It is characterized by re-experiencing trauma, avoidance, hyperarousal, and negative alterations in cognition and mood. Since its formal inclusion in the Diagnostic and Statistical Manual of Mental Disorders (DSM)-III in 1980, PTSD has...
February 20, 2024
Joost J. Breeksema
Psychedelics are remarkable, versatile substances that produce a wide range of effects and can cause both harm and healing. Clinical research into psychedelic treatments is booming. In spite of this renewed interest, relatively little is known about how patients experience these treatments. In this dissertation, patients who received a psychedelic (either ketamine or psilocybin) to a treat...
Scientific Reports
February 5, 2024
Alistair Niemeijer, Erwin Krediet, Jeanine Kamphuis et al.
50 citations
Abstract Psilocybin is the most researched classic psychedelic for Treatment-Resistant Depression (TRD). While optimizing set and setting are considered essential for efficacy and safety, patient perspectives on these aspects have rarely been investigated. To address this knowledge gap, the current paper explored the experiences of 11 TRD patients (8 women, 3 men) participating in a...
Psychopharmacology
July 1, 2023
Joost J. Breeksema, Alistair Niemeijer, Bouwe Kuin et al.
26 citations
Ketamine and its enantiomers are widely researched and increasingly used to treat mental disorders, especially treatment-resistant depression. The phenomenology of ketamine-induced experiences and their relation to its psychotherapeutic potential have not yet been systematically investigated. To describe the phenomenology of patient experiences during oral esketamine treatment for...
Journal of Psychopharmacology
August 26, 2022
Joost J. Breeksema, Bouwe Kuin, Jeanine Kamphuis et al.
171 citations
Introduction: Small-scale clinical studies with psychedelic drugs have shown promising results for the treatment of several mental disorders. Before psychedelics become registered medicines, it is important to know the full range of adverse events (AEs) for making balanced treatment decisions. Objective: To systematically review the presence of AEs during and after administration of...
Frontiers in Psychiatry
2022
Joost J. Breeksema, Alistair Niemeijer, Bouwe Kuin et al.
41 citations
Ketamine and its enantiomer esketamine represent promising new treatments for treatment-resistant depression (TRD). Esketamine induces acute, transient psychoactive effects. How patients perceive esketamine treatment, and which conditions facilitate optimal outcomes, remains poorly understood. Understanding patient perspectives on these phenomena is important to identify unmet needs, which can...
Psychopharmacology
2022
Nina Schimmers, Joost J. Breeksema, Sanne Y Smith-Apeldoorn et al.
Terminally ill patients may experience existential distress, depression, or anxiety, limiting quality of life in the final stage. Existing psychotherapeutic or pharmacological interventions have (time) limited efficacy. Psychedelic treatment may be a safe and effective alternative treatment option. Systematically review studies on psychedelic treatment with and without psychotherapy for...
ACS Pharmacology & Translational Science
July 16, 2021
Joost J. Breeksema, Michiel van Elk
69 citations
In response to a recent call to rid psychedelic science of the concept of mystical experience, we argue that acknowledging the varieties and weirdness of psychedelic experiences should be at the heart of any research program on this topic. We highlight the rich tradition and scientific tools for studying mystical-type experiences, their relevance for understanding the therapeutic effects of...
CNS Drugs
August 17, 2020
Joost J. Breeksema, Alistair Niemeijer, Erwin Krediet et al.
217 citations
This review demonstrates how qualitative research of psychedelic treatments can contribute to distinguishing specific features of specific substances, and carry otherwise undiscovered implications for the treatment of specific psychiatric disorders.
The International Journal of Neuropsychopharmacology
March 12, 2020
Erwin Krediet, Tijmen Bostoen, Joost J. Breeksema et al.
262 citations
Abstract There are few medications with demonstrated efficacy for the treatment of posttraumatic stress disorder (PTSD). Treatment guidelines have unequivocally designated psychotherapy as a first line treatment for PTSD. Yet, even after psychotherapy, PTSD often remains a chronic illness, with high rates of psychiatric and medical comorbidity. Meanwhile, the search for and development of drugs...