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Harriet de Wit

University of Chicago, University of Illinois Chicago

66 papers in the library · 1,670 citations · publishing 1992-2026

Papers

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Repeated low doses of LSD in healthy adults: A placebo-controlled, dose-response study.

Addiction Biology February 1, 2022 Harriet de Wit, Hanna Molla, Anya K. Bershad et al. 82 citations

The resurgence of interest in using psychedelic drugs, including lysergic acid diethylamide (LSD), in psychiatry has drawn attention to the medically unsupervised practice of 'microdosing'. Thousands of users claim that very low doses of LSD, taken at 3-4-day intervals, improve mood and cognitive function., However, few controlled studies have described the effects of the drug when taken in...

DOI: 10.1111/adb.13143 (opens in new tab) Full text (opens in new tab) LSD Microdosing Mood and cognition Clinical research

Acute effects of oral delta-9-tetrahydrocannabinol (THC) on autonomic cardiac activity and their relation to subjective and anxiogenic effects.

Psychophysiology February 2022 Elisa Pabon, Frederica Rockwood, Greg J Norman et al.

Cannabis is the most commonly used psychotropic drug in the United States, after alcohol. Despite its apparent sedative and calming effects, cannabis and its main psychoactive constituent, ∆9 -tetrahydrocannabinol (THC) can produce serious adverse effects including tachycardia and anxiety. These effects can be especially pronounced in women, who remain underrepresented in clinical cannabinoid...

DOI: 10.1111/psyp.13955 (opens in new tab) Full text (opens in new tab) Cannabis Autonomic Delta-9-tetrahydrocannabinol Heart rate variability +1

Does ±3,4-methylenedioxymethamphetamine (ecstasy) induce subjective feelings of social connection in humans? A multilevel meta-analysis

PLoS One October 25, 2021 Annie Regan, Seth Margolis, Harriet de Wit et al. 18 citations

3,4-Methylenedioxymethamphetamine (MDMA) is a psychostimulant known for producing positive subjective effects and for enhancing social functioning and social connection in both clinical and recreational settings. Over the past two decades, scientists have begun to study the psychological effects of MDMA through rigorous placebo-controlled experimental work. However, most existing studies have...

Low doses of LSD reduce broadband oscillatory power and modulate event-related potentials in healthy adults

Psychopharmacology October 6, 2021 Conor H. Murray, Ilaria Tare, Claire Perry et al. 75 citations

Classical psychedelics, including psilocybin and lysergic acid diethylamide (LSD), are under investigation as potential therapeutic agents in psychiatry. Whereas most studies utilize relatively high doses, there are also reports of beneficial effects of “microdosing,” or repeated use of very low doses of these drugs. The behavioral and neural effects of these low doses are not fully understood....

Δ9-Tetrahydrocannabinol (THC) impairs visual working memory performance: a randomized crossover trial.

Neuropsychopharmacology October 1, 2020 Kirsten C. S. Adam, Manoj K. Doss, Elisa Pabon et al. 2 citations

With the increasing prevalence of legal cannabis use and availability, there is an urgent need to identify cognitive impairments related to its use. It is widely believed that cannabis, or its main psychoactive component Δ9-tetrahydrocannabinol (THC), impairs working memory, i.e., the ability to temporarily hold information in mind. However, our review of the literature yielded surprisingly...

Detection of acute 3,4-methylenedioxymethamphetamine (MDMA) effects across protocols using automated natural language processing

Neuropsychopharmacology January 24, 2020 Carla Agurto, Guillermo Cecchi, Raquel Norel et al. 33 citations

Abstract The detection of changes in mental states such as those caused by psychoactive drugs relies on clinical assessments that are inherently subjective. Automated speech analysis may represent a novel method to detect objective markers, which could help improve the characterization of these mental states. In this study, we employed computer-extracted speech features from multiple domains...

Δ9-Tetrahydrocannabinol During Encoding Impairs Perceptual Details yet Spares Context Effects on Episodic Memory.

Biological Psychiatry: Cognitive Neuroscience and Neuroimaging 2020 Manoj K. Doss, Jessica Weafer, David A Gallo et al.

With the growing acceptance of cannabis use, it is crucial to understand the drug's effects on episodic memory accuracy and distortion. We investigated the impact of the administration of Δ9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, on a context-based memory illusion. In a double-blind, placebo-controlled, within-subjects design, healthy infrequent cannabis...

Preliminary Report on the Effects of a Low Dose of LSD on Resting-State Amygdala Functional Connectivity.

Biological Psychiatry: Cognitive Neuroscience and Neuroimaging December 20, 2019 Anya K. Bershad, Katrin H. Preller, Royce Lee et al. 95 citations

BackgroundThe practice of "microdosing," or the use of repeated, very low doses of lysergic acid diethylamide (LSD) to improve mood or cognition, has received considerable public attention, but empirical studies are lacking. Controlled studies are needed to investigate both the therapeutic potential and the neurobiological underpinnings of this pharmacologic treatment.MethodsThe present study...

Δ 9 -Tetrahydrocannabinol (THC) impairs visual working memory performance: A randomized crossover trial

bioRxiv (Cold Spring Harbor Laboratory) September 23, 2019 Kirsten C. S. Adam, Manoj K. Doss, Elisa Pabon et al. 2 citations preprint

Abstract With the increasing prevalence of legal cannabis use and availability, there is an urgent need to identify cognitive impairments related to its use. It is widely believed that cannabis, or its main psychoactive component Δ 9 -tetrahydrocannabinol (THC), impairs working memory, i.e., the ability to temporarily hold information in mind. However, our review of the literature yielded...

Developing a phone-based measure of impairment after acute oral ∆9-tetrahydrocannabinol.

Journal of Psychopharmacology September 1, 2019 Elisa Pabon, Harriet de Wit

Acute consumption of cannabis or its primary psychoactive ingredient ∆9-tetrahydrocannabinol has been shown to impair memory, reaction time, time perception, and attention. However, it is difficult to measure these impairments in a brief test that can be used in a non-laboratory setting. We aim to develop and validate a prototype for a mobile phone application to measure...

Effects of MDMA on attention to positive social cues and pleasantness of affective touch.

Neuropsychopharmacology September 2019 Anya K. Bershad, Leah M. Mayo, Kathryne Van Hedger et al.

The psychostimulant drug ±3,4-methylenedioxymethamphetamine (MDMA) reportedly produces distinctive feelings of empathy and closeness with others. MDMA increases social behavior in animal models and has shown promise in psychiatric disorders, such as autism spectrum disorder (ASD) and post-traumatic stress disorder (PTSD). How it produces these prosocial effects is not known. This behavioral and...

Acute Subjective and Behavioral Effects of Microdoses of Lysergic Acid Diethylamide in Healthy Human Volunteers

Biological Psychiatry June 3, 2019 Anya K. Bershad, Scott T. Schepers, Michael P. Bremmer et al. 176 citations

BackgroundNumerous anecdotal reports suggest that repeated use of very low doses of lysergic acid diethylamide (LSD), known as microdosing, improves mood and cognitive function. These effects are consistent both with the known actions of LSD on serotonin receptors and with limited evidence that higher doses of LSD (100-200 μg) positively bias emotion processing. Yet, the effects of such...

MDMA Impairs Both the Encoding and Retrieval of Emotional Recollections.

Neuropsychopharmacology March 2018 Manoj K. Doss, Jessica Weafer, David A Gallo et al.

The psychoactive drug ±3,4-methylenedioxymethamphetamine (MDMA) is increasingly used for its perceived emotional effects (eg, prosociality, empathy, psychotherapy), but surprisingly little research has been aimed at identifying the effect of the drug on emotional episodic memory in humans. Here, we report the first double-blind placebo-controlled study to examine the effects of MDMA on...

Dose-related effects of delta-9-THC on emotional responses to acute psychosocial stress.

Drug and Alcohol Dependence August 1, 2017 Emma Childs, Joseph A Lutz, Harriet de Wit

Cannabis smokers often report that they use the drug to relax or to relieve emotional stress. However, few clinical studies have shown evidence of the stress-relieving effects of cannabis or cannabinoid agonists. In this study, we sought to assess the influence of delta-9-tetrahydrocannabinol (THC), a main active ingredient of cannabis, upon emotional responses to an acute psychosocial stressor...

MDMA does not alter responses to the Trier Social Stress Test in humans

Psychopharmacology July 1, 2017 Anya K. Bershad, Melissa A. Miller, Harriet de Wit 12 citations

Rationale ±3,4-Methylenedioxymethamphetamine (MDMA, “ecstasy”) is a stimulant-psychedelic drug with unique social effects. It may dampen reactivity to negative social stimuli such as social threat and rejection. Perhaps because of these effects, MDMA has shown promise as a treatment for post-traumatic stress disorder (PTSD). However, the effect of single doses of MDMA on responses to an acute...

Cannabidiol Does Not Dampen Responses to Emotional Stimuli in Healthy Adults.

Cannabis and Cannabinoid Research 2017 David L Arndt, Harriet de Wit

Introduction: Cannabidiol (CBD) is a nonpsychoactive constituent of whole plant cannabis that has been reported to reduce anxiety-like behaviors in both pre-clinical and human laboratory studies. Yet, no controlled clinical studies have demonstrated its ability to reduce negative mood or dampen responses to negative emotional stimuli in humans. The objective of this study was to investigate the...

Urinary and plasma oxytocin changes in response to MDMA or intranasal oxytocin administration.

Psychoneuroendocrinology December 2016 Sunday M. Francis, Matthew G. Kirkpatrick, Harriet de Wit et al.

The neuropeptide oxytocin (OT) has received increased experimental attention for its putative role in both normal social functioning and several psychiatric disorders that are partially characterized by social dysfunction (e.g., autism spectrum disorders: ASD). Many human experimental studies measure circulating plasma levels of OT in order to examine the relationship between the hormone and...

The effects of MDMA on socio-emotional processing: Does MDMA differ from other stimulants?

Journal of Psychopharmacology August 26, 2016 Anya K. Bershad, Melissa A. Miller, Matthew J. Baggott et al. 104 citations

±3,4-Methylenedioxymethamphetamine (MDMA) is a popular recreational drug that enhances sociability and feelings of closeness with others. These “prosocial” effects appear to motivate the recreational use of MDMA and may also form the basis of its potential as an adjunct to psychotherapy. However, the extent to which MDMA differs from prototypic stimulant drugs, such as dextroamphetamine,...

Oxytocin receptor gene variation predicts subjective responses to MDMA

Social Neuroscience January 20, 2016 Anya K. Bershad, Jessica Weafer, Matthew G. Kirkpatrick et al. 35 citations

3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") enhances desire to socialize and feelings of empathy, which are thought to be related to increased oxytocin levels. Thus, variation in the oxytocin receptor gene (OXTR) may influence responses to the drug. Here, we examined the influence of a single OXTR nucleotide polymorphism (SNP) on responses to MDMA in humans. Based on findings that...

DOI: 10.1080/17470919.2016.1143026 (opens in new tab) MDMA Ecstasy Oxytocin receptor Single-nucleotide polymorphism +2

Intimate insight: MDMA changes how people talk about significant others

Journal of Psychopharmacology April 29, 2015 Matthew J. Baggott, Matthew G. Kirkpatrick, Gillinder Bedi et al. 69 citations

Rationale: ±3,4-methylenedioxymethamphetamine (MDMA) is widely believed to increase sociability. The drug alters speech production and fluency, and may influence speech content. Here, we investigated the effect of MDMA on speech content, which may reveal how this drug affects social interactions. Method: Thirty-five healthy volunteers with prior MDMA experience completed this two-session,...

Prosocial effects of MDMA: A measure of generosity

Journal of Psychopharmacology March 4, 2015 Matthew G. Kirkpatrick, Andrew W. Delton, Theresa E. Robertson et al. 86 citations

Background: 3,4-methylenedioxymethamphetamine (MDMA) produces “prosocial” effects that contribute to its recreational use. Few studies have examined the cognitive and behavioral mechanisms by which MDMA produces these effects. Here we examined the effect of MDMA on a specific prosocial effect, i.e. generosity, using a task in which participants make decisions about whether they or another...

DOI: 10.1177/0269881115573806 (opens in new tab) MDMA Generosity Prosocial behavior Developmental psychology +2

Cannabinoid Modulation of Amygdala Subregion Functional Connectivity to Social Signals of Threat

The International Journal of Neuropsychopharmacology December 28, 2014 Stephanie M. Gorka, Daniel A. Fitzgerald, Harriet de Wit et al. 43 citations

BACKGROUND: Δ(9)-Tetrahydrocannabinol has been shown to modulate anxiety and facilitate the extinction of fear by inhibiting amygdala reactivity. Since functional coupling between the amygdala and prefrontal cortex is implicated in affective processes, it is possible that Δ(9)-tetrahydrocannabinol affects amygdala-prefrontal cortex functional connectivity in ways that differ across amygdala...

DOI: 10.1093/ijnp/pyu104 (opens in new tab) Full text (opens in new tab) Tetrahydrocannabinol Basolateral amygdala Ventromedial prefrontal cortex Anterior cingulate cortex +3

MDMA: a social drug in a social context.

Psychopharmacology October 5, 2014 Matthew G. Kirkpatrick, Harriet de Wit 43 citations

RationaleThe drug ±3,4-methylenedioxymethamphetamine (MDMA, "ecstasy," "molly") is thought to produce prosocial effects and enhance social interaction. However, in most laboratory studies to date, the participants have been tested under nonsocial conditions, which may not simulate the effects the drug produces in more naturalistic social settings.MethodsHealthy experienced MDMA users...

Effects of MDMA and Intranasal oxytocin on social and emotional processing.

Neuropsychopharmacology June 2014 Matthew G. Kirkpatrick, Royce Lee, Margaret C. Wardle et al.

MDMA (± 3,4-methylenedioxymethamphetamine, 'ecstasy') is used recreationally, reportedly because it increases feelings of empathy, sociability, and interpersonal closeness. One line of evidence suggests that MDMA produces these effects by releasing oxytocin, a peptide involved in social bonding. In the current study, we investigated the acute effects of MDMA and oxytocin on social and emotional...

Plasma oxytocin concentrations following MDMA or intranasal oxytocin in humans

Psychoneuroendocrinology April 19, 2014 M. Kirkpatrick, Sunday M. Francis, Royce Lee et al. 106 citations

MDMA (±3,4-methylenedioxymethamphetamine, ‘ecstasy’) is reportedly used recreationally because it increases feelings of sociability and interpersonal closeness. Prior work suggests that the pro-social effects of MDMA may be mediated by release of oxytocin. A direct examination of plasma levels of oxytocin after acute doses of oxytocin and MDMA, in the same individuals, would provide further...