JAMA
October 26, 2026
David Feifel, Mathieu Seynaeve, Wiesław Jerzy Cubała et al.
Psychedelics represent a potential breakthrough for treatment-resistant depression; however, the prolonged in-clinic monitoring required for compounds such as psilocybin and lysergic acid diethylamide is a logistical hurdle to widespread use. Intranasal mebufotenin (5-methoxy-N,N-dimethyltryptamine), a 5-hydroxytryptamine 1A (5-HT1A) and 5-HT2A agonist associated with brief psychedelic...
Journal of Psychopharmacology
May 20, 2022
Matthew B. Wall, Tom P. Freeman, Chandni Hindocha et al.
21 citations
Background: Cannabidiol (CBD) and Δ 9 -tetrahydrocannabinol (THC) are the two major constituents of cannabis with contrasting mechanisms of action. THC is the major psychoactive, addiction-promoting, and psychotomimetic compound, while CBD may have opposite effects. The brain effects of these drugs alone and in combination are poorly understood. In particular, the striatum is implicated in the...
Journal of Psychopharmacology
January 9, 2021
Abigail M. Freeman, Claire Mokrysz, Chandni Hindocha et al.
6 citations
BACKGROUND: While the acute effects of cannabis are relatively benign for most users, some individuals experience significant adverse effects. This study aimed to identify whether variation in schizotypal personality traits and frequency of cannabis use influence the acute effects of delta-9-tetrahydrocannabinol (THC). METHODS: Individual participant data from four double-blind, randomised,...
bioRxiv (Cold Spring Harbor Laboratory)
November 21, 2020
Matthew B. Wall, Tom P. Freeman, Chandni Hindocha et al.
4 citations
preprint
Abstract Cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) are two major constituents of cannabis with contrasting mechanisms of action. THC is the major psychoactive, addiction-promoting, and psychotomimetic compound, while CBD may have somewhat opposite effects. The brain effects of these drugs alone and in combination are poorly understood. In particular the striatum is implicated in the...
Journal of Psychopharmacology
August 5, 2020
Will Lawn, J. P. Hill, Chandni Hindocha et al.
23 citations
BACKGROUND: Cannabidiol has potential therapeutic benefits for people with psychiatric disorders characterised by reward function impairment. There is existing evidence that cannabidiol may influence some aspects of reward processing. However, it is unknown whether cannabidiol acutely affects brain function underpinning reward anticipation and feedback. HYPOTHESES: We predicted that cannabidiol...
Translational Psychiatry
May 12, 2020
Chandni Hindocha, Diego Quattrone, Tom P. Freeman et al.
Epidemiological and biological evidence support the association between heavy cannabis use and psychosis. However, it is unclear which cannabis users are susceptible to its psychotogenic effect. Therefore, understanding genetic factors contributing to this relationship might prove an important strategy to identify the mechanisms underlying cannabis-associated psychotic experiences. We aimed to...
Psychological Medicine
April 28, 2020
Claire Mokrysz, Natacha D. C. Shaban, Tom P. Freeman et al.
24 citations
BACKGROUND: Acute cannabis administration can produce transient psychotic-like effects in healthy individuals. However, the mechanisms through which this occurs and which factors predict vulnerability remain unclear. We investigate whether cannabis inhalation leads to psychotic-like symptoms and speech illusion; and whether cannabidiol (CBD) blunts such effects (study 1) and adolescence...
Neuroscience & Biobehavioral Reviews
September 30, 2019
A. Freeman, Kat Petrilli, Rachel Lees et al.
The recent liberalisation of cannabis regulation has increased public and scientific debate about its potential benefits and risks. A key focus has been the extent to which cannabidiol (CBD) might influence the acute effects of delta-9-tetrahydrocannabinol (THC), but this has never been reviewed systematically. In this systematic review of how CBD influences the acute effects of THC we...
Journal of Psychopharmacology
April 23, 2019
Matthew B. Wall, Rebecca Pope, Tom P. Freeman et al.
89 citations
BACKGROUND: -tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the main psychoactive component; CBD may buffer the user against the harmful effects of THC. AIMS: We examined the effects of two strains of cannabis and placebo on the human brain's resting-state networks using fMRI. METHODS: Seventeen healthy volunteers (experienced with cannabis, but not regular users) underwent three drug...
Pharmacology & Therapeutics
October 20, 2018
Michael Bloomfield, Chandni Hindocha, Sebastian F Green et al.
236 citations
receptor. Acutely, cannabis and THC produce a range of effects on several neurocognitive and pharmacological systems. These include effects on executive, emotional, reward and memory processing via direct interactions with the endocannabinoid system and indirect effects on the glutamatergic, GABAergic and dopaminergic systems. Cannabidiol, a non-intoxicating cannabinoid found in some forms of...
Translational Psychiatry
September 5, 2018
Celia J. A. Morgan, Tom P. Freeman, Chandni Hindocha et al.
The main active ingredient in cannabis, delta-9-tetrahydrocannabinol (THC), can acutely induce psychotic symptoms and impair episodic and working memory. Another major constituent, cannabidiol (CBD), may attenuate these effects. This study aimed to determine the effects of THC and CBD, both alone and in combination on psychotic symptoms and memory function. A randomised, double-blind crossover...
Psychological Medicine
September 4, 2018
Helen Valerie Curran, Chandni Hindocha, Celia J. A. Morgan et al.
65 citations
BACKGROUND: Changes in cannabis regulation globally make it increasingly important to determine what predicts an individual's risk of experiencing adverse drug effects. Relevant studies have used diverse self-report measures of cannabis use, and few include multiple biological measures. Here we aimed to determine which biological and self-report measures of cannabis use predict cannabis...
Psychopharmacology
November 2017
Chandni Hindocha, Will Lawn, Tom P. Freeman et al.
Cannabis and tobacco are often smoked simultaneously in joints, and this practice may increase the risks of developing tobacco and/or cannabis use disorders. Currently, there is no human experimental research on how these drugs interact on addiction-related measures. This study aimed to investigate how cannabis and tobacco, each alone and combined together in joints, affected individuals'...
Psychopharmacology
October 30, 2017
J. B. Stroud, Tom P. Freeman, Robert Leech et al.
102 citations
RATIONALE: Depressed patients robustly exhibit affective biases in emotional processing which are altered by SSRIs and predict clinical outcome. OBJECTIVES: The objective of this study is to investigate whether psilocybin, recently shown to rapidly improve mood in treatment-resistant depression (TRD), alters patients' emotional processing biases. METHODS: Seventeen patients with...
The International Journal of Neuropsychopharmacology
August 30, 2017
Tom P. Freeman, Rebecca Pope, Matthew B. Wall et al.
67 citations
Background: Despite the current shift towards permissive cannabis policies, few studies have investigated the pleasurable effects users seek. Here, we investigate the effects of cannabis on listening to music, a rewarding activity that frequently occurs in the context of recreational cannabis use. We additionally tested how these effects are influenced by cannabidiol, which may offset...
Psychological Medicine
May 30, 2017
Chandni Hindocha, Tom P. Freeman, Joanna Xia et al.
104 citations
BACKGROUND: Cannabis and tobacco have contrasting cognitive effects. Smoking cannabis with tobacco is prevalent in many countries and although this may well influence cognitive and mental health outcomes, the possibility has rarely been investigated in human experimental psychopharmacological research. METHOD: The individual and interactive effects of cannabis and tobacco were evaluated in 24...
Cannabis and Cannabinoid Research
2017
Chandni Hindocha, Tom P. Freeman, Helen Valerie Curran
42 citations
Abstract Introduction: Major gaps exist in the measurement of cannabis exposure. The accuracy of self-reported cannabis and tobacco dose per joint is poorly characterized and has never been investigated following acute cannabis/tobacco exposure. Using an innovative “Roll a Joint” paradigm, this study aims to (1) compare estimated and actual dose of cannabis and tobacco per joint at baseline and...
Psychopharmacology
September 2, 2016
Will Lawn, Tom P. Freeman, Rebecca Pope et al.
177 citations
RATIONALE: Anecdotally, both acute and chronic cannabis use have been associated with apathy, amotivation, and other reward processing deficits. To date, empirical support for these effects is limited, and no previous studies have assessed both acute effects of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), as well as associations with cannabis dependence. OBJECTIVES: The objectives of...
European Neuropsychopharmacology
March 2015
Chandni Hindocha, Tom P. Freeman, Gráinne Schäfer et al.
Acute administration of the primary psychoactive constituent of cannabis, Δ-9-tetrahydrocannabinol (THC), impairs human facial affect recognition, implicating the endocannabinoid system in emotional processing. Another main constituent of cannabis, cannabidiol (CBD), has seemingly opposite functional effects on the brain. This study aimed to determine the effects of THC and CBD, both alone and...
Addiction
October 2014
Tom P. Freeman, Celia J. A. Morgan, Chandni Hindocha et al.
(1) To determine whether measured concentrations of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in individuals' own cannabis predict their estimates of drug potency and actual titration; and (2) to ascertain if these effects are influenced by frequency of use and cannabis type. Cross-sectional, naturalistic. Participants' own homes. A total of 247 cannabis users in the United...