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Stefan W. Toennes

Goethe University Frankfurt, University Hospital Frankfurt

40 papers in the library · 1,505 citations · publishing 2010-2026

Papers

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A First-in-Man Study with 4-Fluoroamphetamine Demonstrates it Produces a Mild Psychedelic State

Journal of Psychoactive Drugs January 24, 2019 Kim P. C. Kuypers, E. B. de Sousa Fernandes Perna, Eef L. Theunissen et al. 13 citations

The phenethylamine 4-fluoroamphetamine (4-FA) is a so-called novel psychoactive substance with a chemical structure resembling that of amphetamine and MDMA. Since 4-FA users report their subjective experience ranges between the effects induced by amphetamine and MDMA, and it is known that both substances can produce an altered state of consciousness, this study tests whether 4-FA induces a...

Independent elevation of peripheral oxytocin concentrations and reduction in cognitive empathy during 4‐fluoroamphetamine intoxication

Human Psychopharmacology: Clinical and Experimental October 25, 2018 Patrick C. Dolder, Elizabeth B. de Sousa Fernandes Perna, Natasha L. Mason et al. 6 citations

OBJECTIVES: 4-Fluoroamphetamine (4-FA) is a novel psychoactive substance with a pharmacological profile and reported subjective effects (e.g., empathy) intermediate between 3,4-methylenedioxymethamphetamine (MDMA) and amphetamine. Studies have shown that MDMA and amphetamine increase emotional empathy without affecting cognitive empathy; MDMA simultaneously leads to elevated levels of oxytocin,...

DOI: 10.1002/hup.2680 (opens in new tab) MDMA Empathy Oxytocin Placebo +4

Sub-acute and long-term effects of ayahuasca on affect and cognitive thinking style and their association with ego dissolution

Psychopharmacology August 13, 2018 Malin V. Uthaug, Kim van Oorsouw, Kim P. C. Kuypers et al. 213 citations

RATIONALE: Ayahuasca is a psychotropic plant tea from South America used for religious purposes by indigenous people of the Amazon. Increasing evidence indicates that ayahuasca may have therapeutic potential in the treatment of mental health disorders and can enhance mindfulness-related capacities. Most research so far has focused on acute and sub-acute effects of ayahuasca on mental...

Safety Profile and Neurocognitive Function Following Acute 4-Fluoroamphetamine (4-FA) Administration in Humans

Frontiers in Pharmacology July 6, 2018 Elizabeth B. de Sousa Fernandes Perna, Eef L. Theunissen, Patrick C. Dolder et al. 18 citations

Availability of novel psychoactive substances (NPS) exponentially increased over the last years. Risk evaluations of NPS are hampered by the lack of pharmacological studies in humans on health parameters. The aim of the present study was Tto evaluate safety and neurocognitive function of healthy volunteers (N=12) who received single doses of 100 and 150 mg 4-fluoroamphetamine (4-FA), a...

DOI: 10.3389/fphar.2018.00713 (opens in new tab) Neurocognitive Administration probate law Pharmacology Function biology +3

Drug liking and wanting, not impulsive action or reflection is increased by 4-fluoroamphetamine

Psychopharmacology May 31, 2018 Kim P. C. Kuypers, E. B. de Sousa Fernandes Perna, Patrick C. Dolder et al. 14 citations

BACKGROUND: New psychoactive substances (NPS) are chemical analogues designed to mimic the effects of various classic recreational drugs of abuse including MDMA, LSD, and cannabis. NPS use is associated with concern about the acute and longer-term effects particular substances might have, with abuse and addiction as potential consequences. Impulsivity and sensitivity to the rewarding effects of...

DOI: 10.1007/s00213-018-4931-7 (opens in new tab) Full text (opens in new tab) Addiction Action physics Clinical psychology Cognitive psychology

Neurocognition and subjective experience following acute doses of the synthetic cannabinoid JWH‐018: a phase 1, placebo‐controlled, pilot study

British Journal of Pharmacology November 22, 2017 Eef L. Theunissen, Nadia R. P. W. Hutten, Natasha L. Mason et al. 38 citations

BACKGROUND AND PURPOSE: Synthetic cannabinoids (often sold as Spice or K2) have become a very popular alternative to cannabis due to their easy access and portrayed safety. Controlled studies on the behavioural effects of synthetic cannabinoids are currently lacking, which hampers risk assessments of these compounds. EXPERIMENTAL APPROACH: This is a first attempt to assess the influence of a...

DOI: 10.1111/bph.14066 (opens in new tab) Cannabis Synthetic cannabinoids Placebo Dosing +4

Cannabis and tolerance: acute drug impairment as a function of cannabis use history

Scientific Reports May 26, 2016 Johannes G. Ramaekers, J. H. van Wel, Desirée Spronk et al. 81 citations

Cannabis use history as predictor of neurocognitive response to cannabis intoxication remains subject to scientific and policy debates. The present study assessed the influence of cannabis on neurocognition in cannabis users whose cannabis use history ranged from infrequent to daily use. Drug users (N = 122) received acute doses of cannabis (300 μg/kg THC), cocaine HCl (300 mg) and placebo....

Brain reactivity to alcohol and cannabis marketing during sobriety and intoxication

Addiction Biology January 14, 2016 Elizabeth B. de Sousa Fernandes Perna, Eef Lien Theunissen, Kim P. C. Kuypers et al. 24 citations

Drugs of abuse stimulate striatal dopamine release and activate reward pathways. This study examined the impact of alcohol and cannabis marketing on the reward circuit in alcohol and cannabis users while sober and intoxicated. It was predicted that alcohol and cannabis marketing would increase striatal activation when sober and that reward sensitivity would be less during alcohol and cannabis...

Cannabis and cocaine decrease cognitive impulse control and functional corticostriatal connectivity in drug users with low activity DBH genotypes

Brain Imaging and Behavior December 14, 2015 Johannes G. Ramaekers, J. H. van Wel, Desirée Spronk et al. 61 citations

The dopamine β-hydroxylase (DβH) enzyme transforms dopamine into noradrenaline. We hypothesized that individuals with low activity DBH genotypes (rs1611115 CT/TT) are more sensitive to the influence of cannabis and cocaine on cognitive impulse control and functional connectivity in the limbic 'reward' circuit because they experience a drug induced hyperdopaminergic state compared to individuals...

DOI: 10.1007/s11682-015-9488-z (opens in new tab) Full text (opens in new tab) Cannabis Neuropsychology Cognition Impulse control disorder +2

Single doses of THC and cocaine decrease proficiency of impulse control in heavy cannabis users

British Journal of Pharmacology October 11, 2013 Janelle H. P. van Wel, Kim P. C. Kuypers, Eef L. Theunissen et al. 38 citations

BACKGROUND AND PURPOSE: Cannabis is the most popular drug used in the European Union, closely followed by cocaine. Whereas cannabis impairs neurocognitive function in occasional cannabis users, such impairments appear less prominent in heavy users, possibly as a result of tolerance. The present study was designed to assess whether the impairing effects of Δ(9) -tetrahydrocannabinol (THC) in...

DOI: 10.1111/bph.12425 (opens in new tab) Cannabidiol Impulsivity Psychomotor learning Neurocognitive +8

Argyreia nervosa (Burm. f.): Receptor profiling of lysergic acid amide and other potential psychedelic LSD-like compounds by computational and binding assay approaches

Journal of Ethnopharmacology May 8, 2013 Alexander Paulke, Christian Kremer, Cora Wunder et al. 31 citations

Ethnopharmacological relevanceThe convolvulacea Argyreia nervosa (Burm. f.) is well known as an important medical plant in the traditional Ayurvedic system of medicine and it is used in numerous diseases (e.g. nervousness, bronchitis, tuberculosis, arthritis, and diabetes). Additionally, in the Indian state of Assam and in other regions Argyreia nervosa is part of the traditional tribal...

DOI: 10.1016/j.jep.2013.04.044 (opens in new tab) Traditional medicine Context archaeology Pharmacology

Variable adverse effects in subjects after ingestion of equal doses of Argyreia nervosa seeds.

Forensic Science International January 10, 2012 Christian Kremer, Alexander Paulke, Cora Wunder et al.

As the new drug Spice hit the market in 2006 and was a hot topic in the media, the general issue of legal highs has been brought to the attention of a large number of (young) people. One of these so called legal highs are the seeds of Argyreia nervosa, also known as Hawaiian Baby Woodrose, which contains the psychotropic alkaloid lysergic acid amide (LSA). A study was designed to assess how...

Neurophysiological functioning of occasional and heavy cannabis users during THC intoxication

Psychopharmacology October 5, 2011 Eef L. Theunissen, Gerold F. Kauert, Stefan W. Toennes et al. 82 citations

RATIONALE: Experienced cannabis users demonstrate tolerance to some of the impairing acute effects of cannabis. OBJECTIVES: The present study investigates whether event-related potentials (ERPs) differ between occasional and heavy cannabis users after acute Δ9-tetrahydrocannabinol (THC) administration, as a result of tolerance. METHODS: Twelve occasional and 12 heavy cannabis users participated...

DOI: 10.1007/s00213-011-2479-x (opens in new tab) Full text (opens in new tab) Cannabidiol Delta-9-tetrahydrocannabinol Dronabinol Crossover study +6

MDMA (ecstasy) effects on actual driving performance before and after sleep deprivation, as function of dose and concentration in blood and oral fluid

Psychopharmacology September 27, 2011 Wendy M. Bosker, Kim P. C. Kuypers, Silke Conen et al. 32 citations

RATIONALE: Experimental research has shown that 3,4-methylenedioxymethamphetamine (MDMA) can improve some psychomotor driving skills when administered during the day. In real life, however, MDMA is taken during the night, and driving may likely occur early in the morning after a night of "raving" and sleep loss. OBJECTIVES: The present study assessed the effects of MDMA on road-tracking and...

Tolerance and cross-tolerance to neurocognitive effects of THC and alcohol in heavy cannabis users

Psychopharmacology October 30, 2010 Johannes G. Ramaekers, Eef L. Theunissen, Marjolein de Brouwer et al. 168 citations

INTRODUCTION: Previous research has shown that heavy cannabis users develop tolerance to the impairing effects of Δ9-tetrahydrocannabinol (THC) on neurocognitive functions. Animal studies suggest that chronic cannabis consumption may also produce cross-tolerance for the impairing effects of alcohol, but supportive data in humans is scarce. PURPOSE: The present study was designed to assess...