Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
January 1, 2023
Abigail E. Calder, Gregor Hasler
303 citations
Classic psychedelics like LSD, psilocybin, and ayahuasca may help treat depression, anxiety, and addiction, with clinical improvements lasting months or years. The leading theory is that these drugs rapidly and persistently stimulate neuroplasticity. This review examines evidence that psychedelics promote neuroplasticity, including dendritogenesis, synaptogenesis, neurogenesis, and plasticity-related gene expression, particularly in the prefrontal cortex and hippocampus. It also considers the doses required—hallucinogenic versus microdoses—and how long neuroplastic changes last. The authors discuss consequences for patients and healthy individuals and identify key research questions for future study.
European Neuropsychopharmacology
June 21, 2023
Seline Mock, Nicole Friedli, Patrick Pasi et al.
46 citations
Eating disorders are serious illnesses with high mortality and comorbidity. Psychedelic-assisted therapy shows promise for common comorbidities like mood disorders, PTSD, and substance use disorders, and may also benefit eating disorders themselves. This review summarizes preliminary data on ketamine, MDMA, psilocybin, and ayahuasca for anorexia nervosa, bulimia nervosa, and binge eating disorder. Preliminary evidence suggests psychedelic-assisted therapy may be effective for anorexia and bulimia, with very little data on binge eating disorder. Potential mechanisms include improving body image beliefs, normalizing reward processing, promoting cognitive flexibility, and facilitating trauma processing, alongside general therapeutic factors. Safety concerns and future research recommendations are discussed.
Journal of Psychopharmacology
January 12, 2024
Antonin Rouaud, Gregor Hasler, Abigail E. Calder
36 citations
Microdosing psychedelics like LSD and psilocybin has become popular, but its long-term effects on heart health are unknown. These drugs share structural similarities with medications that raise the risk of cardiac fibrosis and valvulopathy when taken regularly. This review evaluates the evidence that microdosing for months or more could increase the risk of cardiac fibrosis, discusses the role of the 5-HT2B receptor in drug-induced cardiac fibrosis, and recommends safety evaluations for future studies.
Journal of affective disorders
November 15, 2024
Abigail E. Calder, Gregor Hasler
20 citations
A new standardized tool, the Swiss Psychedelic Side Effects Inventory (SPSI), was developed to systematically record clinically relevant side effects of psychedelics and MDMA, including their severity, duration, impact, and treatment-relatedness. The SPSI was constructed from previous research and pilot tested in 145 participants across three studies, with expert panel feedback improving its validity. The final version contains 32 side effects with standardized follow-up questions, compatible with any study design and administrable as interview or self-report. It omits less important side effects but includes space for additional symptoms. The SPSI is available in English and German to improve clinical decisions, informed consent, and patient safety.
Molecular Psychiatry
November 29, 2024
Adrian Hase, Gregor Hasler, Abigail E. Calder
12 citations
A meta-analysis of 29 studies found no evidence that psychoplastogens—including ketamine, LSD, psilocybin, and MDMA—elevate peripheral brain-derived neurotrophic factor (BDNF) levels in humans. The overall effect size was negligible (SMD = 0.024) and not statistically significant. This null result held across different drugs, doses, blood fractions, participant ages, and psychiatric diagnoses. Better-controlled studies showed even smaller effects. The findings suggest that peripheral BDNF may not be a useful biomarker for rapid neuroplasticity changes in humans, or that preclinical findings on psychoplastogen-induced neuroplasticity may not translate to humans. More precise methods, such as neuroimaging, are recommended for future translational research.
Neuropsychopharmacology
June 18, 2026
Abigail E. Calder, Vincent J Diehl, Morten P. Lietz et al.
A single 100 µg dose of lysergic acid diethylamide (LSD) improved offline motor learning the next day and, one week later, reduced perceived stress and increased aspects of cognitive flexibility in 45 healthy adults. Electroencephalography showed that LSD acutely decreased N1 and P2 auditory event-related potential amplitudes, with P2 still modulated after one week. Transcranial magnetic stimulation revealed increased motor-evoked potential amplitude and faster latency under LSD. Brain-derived neurotrophic factor levels were unchanged. The findings suggest lasting effects of LSD on learning and neural signals, while highlighting challenges in measuring long-term potentiation in humans.