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Michael Bloomfield

18 papers in the library · 3,771 citations · publishing 2012-2025

Papers

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Dissociative experiences in individuals with subclinical psychosis and a history of developmental trauma: a qualitative study.

European Journal of Psychotraumatology December 1, 2025 Eirini Aikaterini Melegkovits, Ava J C Mason, Jordan Reid et al. 2 citations

Background: Among individuals with psychotic experiences, those with a history of developmental trauma face greater symptom severity and worse clinical outcomes compared to those without. Dissociation constitutes a prominent, characteristic of this group's clinical presentation, whose nuances and associated characteristics remain however understudied in psychosis research. We aimed to address...

The experience and role of dissociation in psychosis following developmental trauma: A systematic review

Clinical Psychology Review February 26, 2025 Eirini Aikaterini Melegkovits, Rui Tang, Olivia Pounds et al. 8 citations

Developmental trauma (DT), defined as abuse or neglect before age 18, is linked with elevated risk and poorer outcomes in psychosis. This systematic review aimed to elucidate the relationship between DT and dissociation in psychosis and discern the potential mediating role of dissociation in the link between DT and psychotic manifestations. Our study protocol was pre-registered with PROSPERO...

The acute effects of cannabis, with and without cannabidiol, on attentional bias to cannabis related cues: a randomised, double-blind, placebo-controlled, cross-over study

Psychopharmacology February 28, 2024 Daniel L. Hall, Will Lawn, Shelan Ofori et al. 5 citations

RATIONALE: Attentional bias to drug-related stimuli is hypothesised to contribute towards addiction. However, the acute effects of Δ9-tetrahydrocannabinol (THC) on attentional bias to cannabis cues, the differential response in adults and adolescents, and the moderating effect of cannabidiol (CBD) are unknown. OBJECTIVES: Our study investigated (1) the acute effects of vaporised cannabis on...

The acute effects of cannabis with and without cannabidiol in adults and adolescents: A randomised, double‐blind, placebo‐controlled, crossover experiment

Addiction February 8, 2023 Will Lawn, Katie Trinci, Claire Mokrysz et al. 36 citations

Abstract Background and Aims Long‐term harms of cannabis may be exacerbated in adolescence, but little is known about the acute effects of cannabis in adolescents. We aimed to (i) compare the acute effects of cannabis in adolescent and adult cannabis users and (ii) determine if cannabidiol (CBD) acutely modulates the effects of delta‐9‐tetrahydocannabinol (THC). Design Randomised, double‐blind,...

Individual and combined effects of cannabidiol and Δ 9 -tetrahydrocannabinol on striato-cortical connectivity in the human brain

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...

Adjunctive Ketamine With Relapse Prevention–Based Psychological Therapy in the Treatment of Alcohol Use Disorder

American Journal of Psychiatry January 11, 2022 Meryem Grabski, Amy Mcandrew, Will Lawn et al. 169 citations

OBJECTIVE: Early evidence suggests that ketamine may be an effective treatment to sustain abstinence from alcohol. The authors investigated the safety and efficacy of ketamine compared with placebo in increasing abstinence in patients with alcohol use disorder. An additional aim was to pilot ketamine combined with mindfulness-based relapse prevention therapy compared with ketamine and alcohol...

Individual and combined effects of Cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) on striato-cortical connectivity in the human brain

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...

The acute effects of cannabidiol on the neural correlates of reward anticipation and feedback in healthy volunteers

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...

Acute effects of cannabis on speech illusions and psychotic-like symptoms: two studies testing the moderating effects of cannabidiol and adolescence

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...

Dissociable effects of cannabis with and without cannabidiol on the human brain’s resting-state functional connectivity

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...

The neuropsychopharmacology of cannabis: A review of human imaging studies

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...

Psilocybin with psychological support for treatment-resistant depression: six-month follow-up.

Psychopharmacology (Berl) November 8, 2017 R. L. Carhart-Harris, Mark Bolstridge, C. M. J. Day et al. 978 citations

RATIONALE: Recent clinical trials are reporting marked improvements in mental health outcomes with psychedelic drug-assisted psychotherapy. OBJECTIVES: Here, we report on safety and efficacy outcomes for up to 6 months in an open-label trial of psilocybin for treatment-resistant depression. METHODS: Twenty patients (six females) with (mostly) severe, unipolar, treatment-resistant major...

Cannabis Dampens the Effects of Music in Brain Regions Sensitive to Reward and Emotion

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...

Acute and chronic effects of cannabinoids on effort-related decision-making and reward learning: an evaluation of the cannabis ‘amotivational’ hypotheses

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...

Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study.

Lancet Psychiatry May 17, 2016 Robin Carhart-Harris, Mark Bolstridge, James Rucker et al. 1,546 citations

BACKGROUND: Psilocybin is a serotonin receptor agonist that occurs naturally in some mushroom species. Recent studies have assessed the therapeutic potential of psilocybin for various conditions, including end-of-life anxiety, obsessive-compulsive disorder, and smoking and alcohol dependence, with promising preliminary results. Here, we aimed to investigate the feasibility, safety, and efficacy...

The Effects of Acutely Administered 3,4-Methylenedioxymethamphetamine on Spontaneous Brain Function in Healthy Volunteers Measured with Arterial Spin Labeling and Blood Oxygen Level–Dependent Resting State Functional Connectivity

Biological Psychiatry January 10, 2014 Robin Carhart-Harris, Kevin Murphy, Robert Leech et al. 182 citations

The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug's characteristic subjective effects arise from its modulation of spontaneous brain activity.

The effect of acutely administered MDMA on subjective and BOLD-fMRI responses to favourite and worst autobiographical memories

The International Journal of Neuropsychopharmacology December 17, 2013 Robin Carhart-Harris, Matthew B. Wall, David Erritzøe et al. 110 citations

3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine-releaser that is widely used as a recreational drug. Preliminary work has supported the potential of MDMA in psychotherapy for post-traumatic stress disorder (PTSD). The neurobiological mechanisms underlying its putative efficacy are, however, poorly understood. Psychotherapy for PTSD usually requires that patients revisit traumatic...