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Tom P. Freeman

36 papers in the library · 1,165 citations · publishing 2010-2026

Papers

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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...

Additive Effects of 3,4-Methylenedioxymethamphetamine (MDMA) and Compassionate Imagery on Self-Compassion in Recreational Users of Ecstasy

Mindfulness November 4, 2017 Sunjeev K. Kamboj, Ylva Walldén, Caroline J. Falconer et al. 27 citations

3,4-Methylenedioxymethylamphetamine (MDMA;'ecstasy') produces prosocial subjective effects that may extend to affiliative feelings towards the self. Behavioural techniques can produce similar self-directed affiliation. For example, compassionate imagery (CI) and ecstasy reduce self-criticism and increase self-compassion to a similar extent, with the effects of CI enhanced in the presence of...

Psilocybin with psychological support improves emotional face recognition in treatment-resistant depression

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...

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...

Nitrous oxide speeds the reduction of distressing intrusive memories in an experimental model of psychological trauma

Psychological Medicine March 3, 2016 Ravi Das, Amanda J. F. Tamman, Viktoriya L. Nikolova et al. 48 citations

BACKGROUND: Post-traumatic stress disorder (PTSD) involves maladaptive long-term memory formation which underlies involuntary intrusive thoughts about the trauma. Preventing the development of such maladaptive memory is a key aim in preventing the development of PTSD. We examined whether the N-methyl d-aspartate receptor (NMDAR) antagonist gas nitrous oxide (N2O) could reduce the frequency of...

AKT1 genotype moderates the acute psychotomimetic effects of naturalistically smoked cannabis in young cannabis smokers.

Translational Psychiatry February 16, 2016 C J A Morgan, Tom P. Freeman, J Powell et al.

Smoking cannabis daily doubles an individual's risk of developing a psychotic disorder, yet indicators of specific vulnerability have proved largely elusive. Genetic variation is one potential risk modifier. Single-nucleotide polymorphisms in the AKT1 and catechol-O-methyltransferase (COMT) genes have been implicated in the interaction between cannabis, psychosis and cognition, but no studies...

Recreational 3,4-methylenedioxy-N-methylamphetamine (MDMA) or ‘ecstasy’ and self-focused compassion: Preliminary steps in the development of a therapeutic psychopharmacology of contemplative practices

Journal of Psychopharmacology May 18, 2015 Sunjeev K. Kamboj, Emma J. Kilford, Stephanie Minchin et al. 43 citations

3,4-methylenedioxy- N-methylamphetamine (MDMA) produces diverse pro-social effects. Cognitive training methods rooted in Eastern contemplative practices also produce these effects through the development of a compassionate mindset. Given this similarity, we propose that one potential mechanism of action of MDMA in psychotherapy is through enhancing effects on intrapersonal attitudes (i.e....

Sub-chronic impact of cannabinoids in street cannabis on cognition, psychotic-like symptoms and psychological well-being

Psychological Medicine February 1, 2012 C. J. A. Morgan, C. Gardener, G. Schafer et al.

Background Cannabis varies considerably in levels of its two major constituent cannabinoids – (delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Recently, we found evidence that those who smoked cannabis containing detectable levels of CBD had fewer psychotic-like symptoms than those whose cannabis had no CBD. The present study aimed, first, to replicate those findings and, second, to...

Investigating the interaction between schizotypy, divergent thinking and cannabis use

Consciousness and Cognition January 10, 2012 Gráinne Schäfer, Amanda Feilding, Celia J. A. Morgan et al. 60 citations

Cannabis acutely increases schizotypy and chronic use is associated with elevated rates of psychosis. Creative individuals have higher levels of schizotypy, however links between cannabis use, schizotypy and creativity have not been investigated. We investigated the effects of cannabis smoked naturalistically on schizotypy and divergent thinking, a measure of creativity. One hundred and sixty...

Impact of cannabidiol on the acute memory and psychotomimetic effects of smoked cannabis: naturalistic study: naturalistic study [corrected].

The British journal of psychiatry : the journal of mental science October 2010 Celia J A Morgan, Gráinne Schäfer, Tom P Freeman et al.

The two main constituents of cannabis, cannabidiol and Δ(9)-tetrahydrocannabinol (THC), have opposing effects both pharmacologically and behaviourally when administered in the laboratory. Street cannabis is known to contain varying levels of each cannabinoid. To study how the varying levels of cannabidiol and THC have an impact on the acute effects of the drug in naturalistic settings. Cannabis...