Progress in neuro-psychopharmacology & biological psychiatry
February 2, 2018
Simon Reiche, Leo Hermle, Stefan Gutwinski et al.
125 citations
Anxiety and depression are common in people with life-threatening diseases, harming quality of life and prognosis. Serotonergic hallucinogens like LSD and psilocybin were first studied in the 1960s, and interest has recently revived. A systematic review of clinical trials from 1960 to 2017 identified 11 eligible trials with 445 participants: 7 on LSD (323 participants), 3 on psilocybin (92), and 1 on DPT (30). Four more recent randomized controlled trials (104 participants) had higher methodological quality than earlier studies. Evidence supports that these substances reduce anxiety and depression in patients with life-threatening diseases, with anecdotal reports of improved quality of life and reduced fear of death. Side effects were low in studies following safety guidelines.
Frontiers in Psychiatry
November 4, 2021
Ricarda Evens, Simon Reiche, Roman M. Marek et al.
16 citations
During the early COVID-19 pandemic, a survey of over 5,000 people across five languages found that among 1,375 who had used psychedelics in 2019 or 2020, 642 (46.6%) continued using them during the pandemic. Usage shifted away from settings outside the home, and motives changed: less curiosity, celebration, or social influence, more boredom. Positively connoted, often pro-social experiences increased, and two thirds of pandemic users said psychedelics helped them cope with the pandemic at least slightly. The changes likely reflect pandemic restrictions and a possible shift toward safer settings and self-selection.
Frontiers in Pharmacology
September 16, 2021
Lukas A. Basedow, Thomas Riemer, Simon Reiche et al.
16 citations
Repeated use of serotonergic psychedelics such as LSD, ayahuasca, and peyote is associated with distinct neuropsychological profiles rather than a uniform pattern of impairment. A systematic review of 13 studies (539 participants) found that LSD users performed worse on executive-functioning tasks, ayahuasca users showed better performance on the Stroop incongruent task, and peyote users showed no differences across domains. However, methodological quality varied widely, and most studies failed to fully control for confounding factors like other substance use. The evidence suggests that different psychedelics may have different long-term cognitive consequences.
Scientific Reports
December 9, 2020
Timo Torsten Schmidt, Simon Reiche, Caroline L. C. Hage et al.
12 citations
Kambô, the secretion of the Amazonian Giant Leaf Frog, contains many bioactive peptides and was traditionally used by indigenous Amazonian communities as medicine to improve hunting. In Western urban healing circles, its use has spread over the past 20 years. This retrospective study assessed psychological effects in 22 anonymous users using standardized questionnaires for altered states of consciousness. Acute effects were mild to moderate, with no psychedelic-type perceptual or thinking distortions. Persisting effects were predominantly positive, with high scores on personal and spiritual significance.
Progress in neuro-psychopharmacology & biological psychiatry
April 2, 2025
Simon Reiche, Tim Hirschfeld, Anna Lena Gröticke et al.
5 citations
People who have used psychedelics such as psilocybin, LSD, or ayahuasca a mild to moderate number of times over their lives show broadly equivalent neuropsychological performance to non-users, but with a modest advantage in executive functions, particularly cognitive flexibility as measured by the Wisconsin Card Sorting Test (WCST). In matched-pair analyses, users performed better on the WCST, and dose-response analyses within the user group found that greater lifetime use was positively associated with fewer total errors, perseverative responses, perseverative errors, non-perseverative errors, and more conceptual level responses. The study did not find any negative associations between sporadic psychedelic use and cognition.
Scientific Reports
December 31, 2024
Georg Leistenschneider, Tomislav Majić, Simon Reiche et al.
3 citations
Classic psychedelics like LSD and psilocybin show promise for treating psychiatric disorders but can occasionally cause lasting psychological harm, including Hallucinogen Persisting Perception Disorder (HPPD), a rare condition with enduring perceptual symptoms. This study examined the neuropsychological profiles of eight individuals with HPPD using a comprehensive test battery, comparing their performance against normative data and two matched control groups (with and without prior psychedelic use). Some participants with HPPD scored below average on tests of visual memory and executive function. Statistically adjusted comparisons found no significant differences between groups, though unadjusted analyses hinted at impaired executive functions in HPPD patients. These preliminary findings highlight the need for more focused research on the neuropsychological aspects of HPPD.
bioRxiv (Cold Spring Harbor Laboratory)
July 24, 2020
Timo Torsten Schmidt, Simon Reiche, Caroline L. C. Hage et al.
preprint
Kambô, the secretion of the Giant Leaf Frog (Phyllomedusa bicolor), is ritually used by Amazonian ethnicities against bad luck in hunting and has spread to Western urban centers, often alongside ayahuasca. A retrospective study of 22 anonymous users (mean age 39 years, 45.5% female) assessed acute and subacute psychological effects with standardized questionnaires. Acutely, participants reported mild to moderate psychological effects without psychedelic-type perceptual or thinking distortions. Persisting effects were predominantly positive and pleasant, with surprisingly high personal and spiritual significance. Subacute and long-term effects overlapped with the 'afterglow' phenomena following serotonergic psychedelics.
The International journal on drug policy
April 1, 2022
Antonia Bendau, Leonard Viohl, Moritz Bruno Petzold et al.
During the early COVID-19 pandemic, use of party drugs (stimulants, dissociatives, GHB/GBL) shifted substantially. Among 1,231 users surveyed, 48.0–64.8% ceased or decreased use, 11.9–25.5% maintained, and 23.6–29.1% increased consumption. MDMA/ecstasy showed the strongest decrease; GHB/GBL and dissociatives the highest increase. Price, quality, and supply remained mostly unaffected. Mood-related motivations (e.g., feeling exhilarated or high) were common before and during the pandemic, but social and mood-related reasons declined while coping with boredom rose. 16.4–35.6% found drug use helpful for pandemic-related stressors, which was linked to increased consumption. The findings suggest that users who increased use as a coping strategy may need targeted preventive measures.