International Journal of Legal Medicine
August 12, 2026
Stefanie Plenzig, Friederike Pijahn, Alexander Müller et al.
Abstract A man in his early twenties had been hospitalized due to acute nitrous oxide intoxication, during which a vitamin B12 deficiency and anaemia were also diagnosed. Two weeks later he was found dead in his apartment. Twenty empty nitrous oxide cartridges were found next to the body, and according to his mother, he had been using nitrous oxide excessively for approximately two months. The...
bioRxiv (Cold Spring Harbor Laboratory)
July 13, 2026
Natasha L. Mason, Eline Chm Haijen-Bongers, Kim P. C. Kuypers et al.
Serotonergic psychedelics are advancing as psychiatric treatments, yet acute responses vary between individuals and the contribution of sex, a fundamental biological variable, remains largely unexamined. We pooled two double-blind, placebo-controlled studies in healthy volunteers (N = 72; 31 male, 41 female) comparing psilocybin 15 mg, 2C-B 20 mg, and LSD 50 μg. Linear mixed models tested sex...
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie
June 1, 2026
Francisco Madrid-Gambin, Pablo Mallaroni, Noemí Haro et al.
Ayahuasca is a psychoactive brew containing N,N-dimethyltryptamine (DMT) and β-carboline alkaloids that induces marked alterations in perception, emotion and self-referential processing. However, the multiscale biological organization linking peripheral metabolism, brain network dynamics, neurochemistry, and subjective experience in humans remains poorly understood. Here, we applied an...
November 17, 2025
Krishna Prasad Bhavaraju, Natasha L. Mason, Pablo Mallaroni et al.
preprint
Abstract Psilocybin induces profound alterations in consciousness, yet prevailing neural models often describe a monolithic change in brain connectivity that may not fully capture the multifaceted nature of the psychedelic state. To test the hypothesis of a composite neural state, this study applied a robust, data-driven framework, Connectome Independent Component Analysis (connICA) with...
Biological Psychiatry
October 21, 2025
Katharina S Lege, Pablo Mallaroni, Sepehr Mortaheb et al.
1 citation
Background The impact of acute cannabis exposure on brain function and cognitive performance varies among individuals. Acute effects of cannabis on behavior may be absent or benign in chronic users, while occasional users experience significant impairment in day-to-day operations. It is hypothesized that repeated cannabis use induces neuroadaptations leading to tolerance and desensitization,...
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
June 1, 2025
Johannes G. Ramaekers, Johannes T. Reckweg, Natasha L. Mason et al.
8 citations
3-Methylmethcathinone (3-MMC) is a designer drug that belongs to the group of synthetic cathinones. The compound has been scheduled in many jurisdictions because of public health concerns associated with excessive use. To date, there are no clinical studies that have evaluated the risk profile of 3-MMC in the recreational range of low to moderate doses. The current, first-in-human study (N =...
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
May 1, 2025
Francisco Madrid-Gambin, Noemí Haro, Natasha L. Mason et al.
4 citations
Acute intoxication from Δ9-tetrahydrocannabinol (THC, the primary active ingredient of cannabis) can lead to neurocognitive impairment and interference with day-to-day operations, such as driving. Present evaluations of THC-induced impairment in legal settings rely on biological drug tests that solely establish cannabis use, rather than cannabis impairment. The current study evaluated the...
Psychopharmacology
April 30, 2025
Johannes G. Ramaekers, Johannes T. Reckweg, Natasha L. Mason et al.
4 citations
3-Methylmethcathinone (3-MMC) is a synthetic cathinone that has been scheduled in many jurisdictions after it appeared on the consumer market as a designer drug or "legal high". At present, there are no medical applications for synthetic cathinones, but in the past cathinone and other compounds that are structurally related to amphetamine have been evaluated and recognized for their intrinsic...
Neuroimage
2024
Pablo Mallaroni, Natasha L. Mason, Lilian Kloft et al.
17 citations
The knowledge that brain functional connectomes are unique and reliable has enabled behaviourally relevant inferences at a subject level. However, whether such "fingerprints" persist under altered states of consciousness is unknown. Ayahuasca is a potent serotonergic psychedelic which produces a widespread dysregulation of functional connectivity. Used communally in religious ceremonies, its...
Clinical Pharmacology & Therapeutics
May 30, 2023
Pablo Mallaroni, Riccardo Paci, Sabrina Ritscher et al.
34 citations
2,5‐dimethoxy‐4‐bromophenethylamine (2C‐B) is a hallucinogenic phenethylamine derived from mescaline. Observational and preclinical data have suggested it to be capable of producing both subjective and emotional effects on par with other classical psychedelics and entactogens. Whereas it is the most prevalently used novel serotonergic hallucinogen to date, it's acute effects and distinctions...
Journal of Cognitive Neuroscience
2023
Johannes G. Ramaekers, Pablo Mallaroni, Lilian Kloft et al.
15 citations
Abstract Consumption of the psychedelic brew ayahuasca is a central ritualistic aspect of the Santo Daime religion. The current observational, baseline controlled study was designed to assess whether members (n = 24) of the Santo Daime church would show enhanced capacity for mental imagery during an ayahuasca experience. In addition, this study assessed whether the effects of ayahuasca on...
bioRxiv (Cold Spring Harbor Laboratory)
October 11, 2022
Pablo Mallaroni, Natasha L. Mason, Lilian Kloft et al.
4 citations
preprint
Abstract The knowledge that brain functional connectomes are both unique and reliable has enabled behaviourally relevant inferences at a subject level. However, it is unknown whether such “fingerprints” persist under altered states of consciousness. Ayahuasca is a potent serotonergic psychedelic which elicits a widespread dysregulation of functional connectivity. Used communally in religious...
Biomedicine & Pharmacotherapy
March 24, 2022
Francisco Madrid-Gambin, Alex Gomez-Gomez, Arnau Busquets-García et al.
14 citations
There has been a renewed interest in the potential use of psychedelics for the treatment of psychiatric conditions. Nevertheless, little is known about the mechanism of action and molecular pathways influenced by ayahuasca use in humans. Therefore, for the first time, our study aims to investigate the human metabolomics signature after consumption of a psychedelic, ayahuasca, and its connection...
Scientific Reports
February 14, 2022
Johannes G. Ramaekers, Natasha L. Mason, Stefan W. Toennes et al.
26 citations
Resting state fMRI has been employed to identify alterations in functional connectivity within or between brain regions following acute and chronic exposure to Δ9-tetrahydrocannabinol (THC), the psychoactive component in cannabis. Most studies focused a priori on a limited number of local brain areas or circuits, without considering the impact of cannabis on whole-brain network organization....
European Neuropsychopharmacology
February 3, 2022
Lilian Kloft, Henry Otgaar, Arjan Blokland et al.
17 citations
The entactogen 3,4-Methylenedioxymethamphetamine (MDMA) is increasingly being recognized for its therapeutic potential but is also widespread in nightlife settings where it may co-occur with crime. Since previous research detected impaired verbal memory during acute MDMA intoxication, understanding the drug's ramifications in an applied legal context becomes crucial. We conducted a...
Frontiers in Pharmacology
October 1, 2021
Maggie Kiraga, Natasha L. Mason, Malin V. Uthaug et al.
83 citations
Background: Naturalistic and placebo-controlled studies have suggested that ayahuasca, a traditional Amazonian beverage, could be helpful in the treatment of psychopathologies like depression and anxiety disorders by changing otherwise disturbed cognitive and emotional processes. To better understand its full therapeutic potential, one way is to study the effects on processes like flexible...
Translational Psychiatry
April 8, 2021
Natasha L. Mason, Kim P. C. Kuypers, Johannes T. Reckweg et al.
132 citations
Abstract Creativity is an essential cognitive ability linked to all areas of our everyday functioning. Thus, finding a way to enhance it is of broad interest. A large number of anecdotal reports suggest that the consumption of psychedelic drugs can enhance creative thinking; however, scientific evidence is lacking. Following a double-blind, placebo-controlled, parallel-group design, we...
Psychopharmacology
March 10, 2021
Malin V. Uthaug, Natasha L. Mason, Stefan W. Toennes et al.
116 citations
Abstract Ayahuasca is a plant concoction containing N,N -dimethyltryptamine (DMT) and certain β-carboline alkaloids from South America. Previous research in naturalistic settings has suggested that ingestion of ayahuasca can improve mental health and well-being; however, these studies were not placebo controlled and did not control for the possibility of expectation bias. This naturalistic...
Psychopharmacology
January 26, 2021
Eef L. Theunissen, Johannes T. Reckweg, Nadia R. P. W. Hutten et al.
20 citations
BACKGROUND: Synthetic cannabinoids (SCs) are the largest class of novel psychoactive substances (NPS) and are associated with an increased risk of overdosing and adverse events such as psychosis. JWH-018 is one of the earliest SCs and still widely available in large parts of the world. Controlled studies to assess the safety and behavioural profiles of SCs are extremely scarce. AIM: The current...
Frontiers in Pharmacology
2021
Johannes T. Reckweg, Natasha L. Mason, Cees van Leeuwen et al.
58 citations
5-Methoxy-N,N-Dimethyltryptamine (5-MeO-DMT) is a tryptamine with ultra-rapid onset and short duration of psychedelic effects. Prospective studies for other tryptamines have suggested beneficial effects on mental health outcomes. In preparation for a study in patients with depression, the present study GH001-HV-101 aimed to assess the impact of four different dose levels of a novel vaporized...
Proceedings of the National Academy of Sciences
February 10, 2020
Lilian Kloft, Henry Otgaar, Arjan Blokland et al.
49 citations
With the growing global acceptance of cannabis and its widespread use by eyewitnesses and suspects in legal cases, understanding the popular drug's ramifications for memory is a pressing need. In a double-blind, randomized, placebo-controlled trial, we examined the acute and delayed effects of Δ9-tetrahydrocannabinol (THC) intoxication on susceptibility to false memory in 64 healthy volunteers....
Addiction Biology
December 22, 2019
Natasha L. Mason, Eef L. Theunissen, Nadia R. P. W. Hutten et al.
58 citations
Cannabis is the most commonly used illicit drug in the world. However, because of a changing legal landscape and rising interest in therapeutic utility, there is an increasing trend in (long-term) use and possibly cannabis impairment. Importantly, a growing body of evidence suggests that regular cannabis users develop tolerance to the impairing, as well as the rewarding, effects of the drug....
European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology
December 1, 2019
Natasha L. Mason, Eef L. Theunissen, Nadia R. P. W. Hutten et al.
Cannabis is the most commonly used illicit drug and is known to alter state of consciousness and impair neurocognitive function. However, the mechanisms underlying these effects have yet to be fully elucidated. Rodent studies suggest that Δ9-tetrahydrocannabinol (THC) activates dopaminergic neurons in the limbic system, subsequently enhancing dopamine, which is implicated in the rewarding...
bioRxiv (Cold Spring Harbor Laboratory)
July 19, 2019
Natasha L. Mason, Eef L. Theunissen, Nadia R. P. W. Hutten et al.
4 citations
preprint
Abstract Cannabis is the most commonly used illicit drug in the world. However due to a changing legal landscape, and rising interest in therapeutic utility, there is an increasing trend in (long-term) use and possibly, cannabis impairment. Importantly, a growing body of evidence suggests regular cannabis users develop tolerance to the impairing, as well as the rewarding, effects of the drug....
Drug Testing and Analysis
March 26, 2019
Stefan W. Toennes, David J. Schneider, Werner Pogoda et al.
9 citations
INTRODUCTION: Each year, synthetic drugs occur in high numbers on the illicit drug market. But data on their pharmacology and toxicology are scarce. Therefore, a controlled study was performed to evaluate pharmacokinetic parameters of 4-fluoroamphetamine (4-FA) in humans and to compare it with effects. METHODS: Twelve subjects ingested 100 mg and five subjects also received 150 mg 4-FA in a...