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Thomas Riemer

5 papers in the library · 36 citations · publishing 2021-2026

Papers

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Persisting Psychological Complications Following the Use of Classic Psychedelics: A Qualitative Study of Help-Seeking Experiences

medRxiv Preprint Server May 23, 2026 Lisa Maria Jöbstl, Bente Lubahn, Ebru Kaya et al. preprint

Background While growing enthusiasm for the therapeutic potential of classic psychedelics has led to a rise in non-clinical use, attention to persisting adverse effects has emerged with delay. A subset of individuals reports persisting complications such as hallucinogen persisting perception disorder (HPPD), depersonalization/derealization disorder (DDD), anxiety and depression. Yet few medical...

The Afterglow Inventory (AGI): Validation of a new instrument for measuring subacute effects of classic serotonergic psychedelics

Journal of Psychopharmacology March 31, 2025 Tomislav Majić, Timo Torsten Schmidt, Anna Gröticke et al. 4 citations

Background: Classic psychedelics such as psilocybin and lysergic acid diethylamide are anecdotally associated with the phenomenon of “psychedelic afterglow,” a set of predominantly pleasant, temporary psychological effects reported after the acute effects have subsided. Since post-acute effects are crucial for the therapeutic use of psychedelics, an instrument to systematically assess subacute...

Neuropsychological profiles of patients suffering from hallucinogen persisting perception disorder (HPPD): A comparative analysis with psychedelic-using and non-using controls

Scientific Reports December 31, 2024 Georg Leistenschneider, Tomislav Majić, Simon Reiche et al. 3 citations

Abstract Classic psychedelics like LSD and psilocybin are showing promising effects in treating certain psychiatric disorders. Despite their low toxicity and lack of an addictive potential, in some individuals, psychedelics can be associated with persisting psychological harms. Hallucinogen Persisting Perception Disorder (HPPD) is one of those complications, a rare disorder characterized by...

Cognitive functioning associated with acute and subacute effects of classic psychedelics and MDMA - a systematic review and meta-analysis.

Scientific Reports June 26, 2024 Lukas A Basedow, Tomislav Majić, Nicklas Jakob Hafiz et al. 13 citations

Classic psychedelics and MDMA have a colorful history of recreational use, and both have recently been re-evaluated as tools for the treatment of psychiatric disorders. Several studies have been carried out to assess potential long-term effects of a regular use on cognition, delivering distinct results for psychedelics and MDMA. However, to date knowledge is scarce on cognitive performance...

Neuropsychological Functioning in Users of Serotonergic Psychedelics – A Systematic Review and Meta-Analysis

Frontiers in Pharmacology September 16, 2021 Lukas A Basedow, Thomas Riemer, Simon Reiche et al. 16 citations

Background: Serotonergic psychedelics (SPs) like LSD, psilocybin, DMT, and mescaline are a heterogeneous group of substances that share agonism at 5-HT 2a receptors. Besides the ability of these substances to facilitate profoundly altered states of consciousness, persisting psychological effects have been reported after single administrations, which outlast the acute psychedelic effects. In...