Tom P. Freeman
University College London
PsychiatryPsychologyCannabidiolCannabisClinical psychology
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Publications 135
#1Claire Mokrysz (UCL: University College London)H-Index: 10
#2Natacha D. C. Shaban (UCL: University College London)H-Index: 3
Last. Cja Morgan (University of Exeter)H-Index: 36
view all 12 authors...
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 heightens such effects (study 2). METHODS: Two double-blind placebo-controlled studies, assessing speech illus...
#1Musa Sami (University of Nottingham)H-Index: 5
#2Diego Quattrone ('KCL': King's College London)H-Index: 10
Last. Ilaria Tarricone (UNIBO: University of Bologna)H-Index: 17
view all 25 authors...
BACKGROUND: First episode psychosis (FEP) patients who use cannabis experience more frequent psychotic and euphoric intoxication experiences compared to controls. It is not clear whether this is consequent to patients being more vulnerable to the effects of cannabis use or to their heavier pattern of use. We aimed to determine whether extent of use predicted psychotic-like and euphoric intoxication experiences in patients and controls and whether this differs between groups. METHODS: We analysed...
#1Edward Chesney ('KCL': King's College London)H-Index: 3
#2Dominic Oliver ('KCL': King's College London)H-Index: 8
Last. Philip McGuire (NIHR: National Institute for Health Research)H-Index: 110
view all 8 authors...
Cannabidiol (CBD) is being investigated as a treatment for several medical disorders but there is uncertainty about its safety. We conducted the first systematic review and meta-analysis of the adverse effects of CBD across all medical indications. Double-blind randomized placebo-controlled clinical trials lasting >/=7 days were included. Twelve trials contributed data from 803 participants to the meta-analysis. Compared with placebo, CBD was associated with an increased likelihood of withdrawal...
#1Diego Quattrone ('KCL': King's College London)H-Index: 10
#2Laura Ferraro (University of Palermo)H-Index: 10
Last. Charlotte Gayer-Anderson ('KCL': King's College London)H-Index: 13
view all 41 authors...
BACKGROUND: Daily use of high-potency cannabis has been reported to carry a high risk for developing a psychotic disorder. However, the evidence is mixed on whether any pattern of cannabis use is associated with a particular symptomatology in first-episode psychosis (FEP) patients. METHOD: We analysed data from 901 FEP patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study...
Abstract Acute and chronic exposure to cannabis and its main psychoactive component, 9-tetrahydrocannabinol (THC), is associated with changes in brain function and cerebral blood flow (CBF). We therefore sought to systematically review the literature on the effects of THC on CBF following PRISMA guidelines. Studies assessing the acute and chronic effects of THC on CBF, perfusion and volume were searched in the PubMed database between January 1972 and June 2019. We included thirty-four studies, w...
#1Tom P. Freeman (University of Bath)H-Index: 22
#2Valentina Lorenzetti (ACU: Australian Catholic University)H-Index: 21
10 CitationsSource
#1Diego Quattrone ('KCL': King's College London)H-Index: 10
#2Ulrich Reininghaus (Heidelberg University)
Last. M. Di Forti ('KCL': King's College London)H-Index: 36
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Background Diagnostic categories within the psychosis spectrum are widely used in clinical practice, however psychosis may occur on a continuum. Therefore, we explored whether the continuous distribution of psychotic symptoms across categories is a function of genetic as well as environmental risk factors, such as polygenic risk scores (PRSs) and cannabis use. Methods As part of the EU-GEI study, we genotyped first episode psychosis patients (FEP) and population controls, for whom transdiagnosti...
#1M. Di FortiH-Index: 36
#2Beatrice Wu-Choi (ISMMS: Icahn School of Medicine at Mount Sinai)
Last. Robin M. MurrayandH-Index: 149
view all 36 authors...
Background: Some recent studies have challenged the direction of causality for the association between cannabis use and psychotic disorder, suggesting that cannabis use initiation is explained by common genetic variants associated with risk of schizophrenia. We used data from the European Union Gene-Environment Interaction consortium (EUGEI) case-control study to test for the independent and combined effect of heavy cannabis use, and of Schizophrenia Polygenic risk score (SZ PRS), on risk for ps...
#2Robert McCutcheon (Imperial College London)H-Index: 12
Last. Oliver D. Howes (Imperial College London)H-Index: 52
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Chronic psychosocial adversity induces vulnerability to mental illnesses. Animal studies demonstrate that this may be mediated by dopaminergic dysfunction. We therefore investigated whether long-term exposure to psychosocial adversity was associated with dopamine dysfunction and its relationship to psychological and physiological responses to acute stress. Using 3,4-dihydroxy-6-[18F]-fluoro-l-phenylalanine ([18F]-DOPA) positron emission tomography (PET), we compared dopamine synthesis capacity i...
#1Tom P. Freeman (University of Bath)H-Index: 22
#2Cja Morgan (University of Exeter)H-Index: 36
Last. Chandni Hindocha (UCL: University College London)H-Index: 13
view all 3 authors...
Alternative trial designs and patient registries can rapidly generate robust data on efficacy and safety
1 CitationsSource