Current topics in behavioral neurosciences
April 29, 2025
Abigail E Calder, Vincent J Diehl, Gregor Hasler
14 citations
Psychedelic experiences that involve extreme horror, helplessness, or perceived threats can be traumatizing. Such traumatic psychedelic experiences are rare, extreme, and largely preventable, arising from frightening drug effects, unsafe settings, or the emergence of pre-existing trauma. While some people recover quickly, others develop prolonged anxiety, sleep disturbances, derealization, or other trauma-related symptoms. The chapter covers causes, phenomenology, potential outcomes, prevention, and strategies to minimize negative impact.
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.
Journal of psychopharmacology (Oxford, England)
May 1, 2026
Vincent J Diehl, Abigail E Calder, Gregor Hasler
A new questionnaire, the Helioscope Questionnaire, measures how psychedelics such as psilocybin and MDMA alter the processing of traumatic memories during an experience, a process called the helioscope effect. In an online survey of 468 people who had used psychedelics or MDMA, the 21-item scale captured three factors: protection, exposure, and avoidant-distress. A composite score from protection and exposure subscales predicted positive changes in mood and attitude afterward, while avoidant-distress predicted negative changes. Having a trip sitter was linked to stronger protection and exposure scores, and MDMA use was linked to less avoidant-distress. The scale adds a new way to assess therapeutic mechanisms beyond existing measures.