Psychopharmacology
October 17, 2026
Giada Lombardi, Grace Blest‐hopley, Martina Maria Tarantini et al.
RATIONALE: Regular cannabis use has been associated with alterations in reward-related neural processes, yet findings remain inconsistent and the relationship between neural activity and behavioural performance is not fully understood. OBJECTIVES: The present study aimed to characterise neural and behavioural correlates of reward processing in regular cannabis users (CU) compared with matched...
medRxiv Preprint Server
April 23, 2026
Giada Lombardi, Grace Blest‐hopley, Martina Maria Tarantini et al.
preprint
Regular cannabis use has been associated with alterations in reward-related neural processes, yet findings remain inconsistent and the relationship between neural activity and behavioural performance is not fully understood. The present study aimed to characterise neural and behavioural correlates of reward processing in regular cannabis users (CU) compared with matched non-users (NU) using the...
Psychological Medicine
October 17, 2023
Cathy Davies, Matthijs Geert Bossong, Daniel Martins et al.
9 citations
ABSTRACT Background Hippocampal hyperperfusion has been observed in people at Clinical High Risk for Psychosis (CHR), is associated with adverse longitudinal outcomes and represents a potential treatment target for novel pharmacotherapies. Whether cannabidiol (CBD) has ameliorative effects on hippocampal blood flow (rCBF) in CHR patients remains unknown. Methods Using a double-blind,...
bioRxiv (Cold Spring Harbor Laboratory)
November 3, 2021
Brandon Gunasekera, Cathy Davies, Grace Blest‐hopley et al.
preprint
Abstract Background The neurobiological mechanisms underlying the effects of delta-9-tetrahydrocannabinol (THC) remain unclear. Here, we examined the spatial acute effect of THC on human on regional brain activation or blood flow (hereafter called ‘activation signal’) in a ‘core’ network of brain regions that subserve a multitude of processes. We also investigated whether the neuromodulatory...
Schizophrenia
May 12, 2021
Musa Basseer Sami, Luciano Annibale, Aisling O’neill et al.
5 citations
Abstract It is unclear whether early psychosis in the context of cannabis use is different from psychosis without cannabis. We investigated this issue by examining whether abnormalities in oculomotor control differ between patients with psychosis with and without a history of cannabis use. We studied four groups: patients in the early phase of psychosis with a history of cannabis use (EPC; n =...
Psychological Medicine
October 27, 2020
Marco Colizzi, Nathalie Weltens, David J Lythgoe et al.
8 citations
Abstract Background Cannabis use has been associated with psychosis through exposure to delta-9-tetrahydrocannabinol (Δ9-THC), its key psychoactive ingredient. Although preclinical and human evidence suggests that Δ9-THC acutely modulates glial function and hypothalamic-pituitary-adrenal (HPA) axis activity, whether differential sensitivity to the acute psychotomimetic effects of Δ9-THC is...
Frontiers in Psychology
May 14, 2020
Marco Colizzi, Mirella Ruggeri, Sagnik Bhattacharyya
50 citations
Research evidence suggests a dose-response relationship for the association between cannabis use and risk of psychosis. Such relationship seems to reflect not only an increased risk of psychosis as a function of frequent cannabis use, but also of high-potency cannabis use in terms of concentration of delta-9-tetrahydrocannabinol (∆9-THC), its main psychoactive component. This finding would be...
Translational Psychiatry
April 21, 2020
Musa Sami, Amanda Worker, Marco Colizzi et al.
AbstractThe associative striatum, an established substrate in psychosis, receives widespread glutamatergic projections. We sought to see if glutamatergic indices are altered between early psychosis patients with and without a history of cannabis use and characterise the relationship to grey matter. 92 participants were scanned: Early Psychosis with a history of cannabis use (EPC = 29); Early...
Schizophrenia Bulletin Open
2020
Musa Sami, Robert A. McCutcheon, Ulrich Ettinger et al.
Both chronic cannabis use and psychotic disorders are associated with abnormalities in visual attentional processing. Using functional magnetic resonance imaging (fMRI), we sought to determine whether there would be a difference in functional connectivity in patients and controls with and without a history of cannabis use in the visual and dorsal attention networks. Resting-state fMRI data were...
2020
Marco Colizzi, Sagnik Bhattacharyya
Abstract Accumulating evidence suggests an association between cannabis use and psychosis. However, some concerns have been raised about the nature of this association, particularly whether it might be driven by other factors such as use of other substances. Another explanation would bring into play preexisting differences among cannabis users and nonusers in terms of psychosis-related...
Neuroscience & Biobehavioral Reviews
2019
Grace Blest‐hopley, Vincent Giampietro, Sagnik Bhattacharyya
HighlightsAdolescent abstinent cannabis users showed significantly greater activation in the dorsolateral and ventrolateral prefrontal and posterior parietal cortices compared to controls.Adolescent users showed increased activation in regions involved in executive functioning, attentional control and the default mode network compared to non‐using controls.No significant group differences in...
Psychological Medicine
December 2018
Subhadip Paul, Sagnik Bhattacharyya
Although alterations in medial temporal lobe structures have been previously associated with use of cannabis, one of the most widely used illicit drugs, whether such alterations are a cause or effect of cannabis use has been unclear. In this cross-sectional observational study involving 404 twins/siblings, we have compared cortical thickness and surface area between groups of gender-matched...
Experimental and Clinical Psychopharmacology
December 2018
Marco Colizzi, Philip Mcguire, Vincent Giampietro et al.
Cannabis can induce transient psychotic and anxiety symptoms and long-lasting disorders. The acute psychoactive effects of its main active ingredient, (-)-trans-Δ9-tetrahydrocannabinol (Δ9-THC), may be modulated by previous cannabis exposure. Secondary data analyses tested whether modest previous cannabis exposure modulated the acute effects of Δ9-THC on attentional salience and emotional...
Neuroscience & Biobehavioral Reviews
October 2018
Marco Colizzi, Sagnik Bhattacharyya
Previous studies have reported conflicting results in terms of acute effects of cannabis in man. Independently of other factors, such discrepancy may be attributable to the different cannabis use history of study volunteers. It is thought that regular cannabis users may develop tolerance to the effects of acute cannabis administration. Here we systematically review all studies examining the...
European Neuropsychopharmacology
July 1, 2018
Marco Colizzi, P. McGuire, Vincent Giampietro et al.
Cannabis use has been associated with psychosis and cognitive dysfunction. Some evidence suggests that the acute behavioral and neurocognitive effects of the main active ingredient in cannabis, (-)-trans-Δ9-tetrahydrocannabinol (∆9-THC), might be modulated by previous cannabis exposure. However, this has not been investigated either using a control group of non-users, or following abstinence in...
Schizophrenia Bulletin
April 1, 2018
Grace Blest‐hopley, Aisling O'Neill, R. Wilson et al.
Abstract Background Long-term use of cannabis has long been associated with changes in cognition, including memory and learning, particularly verbal learning in man. However, evidence regarding the neurobiological underpinnings of impairments in memory following long-term cannabis use has not been consistent. Furthermore, to our knowledge none of the studies published to date have specifically...
Psychological Medicine
March 23, 2018
Musa Basseer Sami, Caitlin Jade Notley, Christos Kouimtsidis et al.
25 citations
BACKGROUND: Evidence suggests that cannabis-induced psychotic-like experiences may be a marker of psychosis proneness. The effect of such experiences on cannabis use has not systematically been examined. METHODS: We undertook a mixed-methods online survey of 1231 cannabis users (including 926 continued users) using the Cannabis Experiences Questionnaire. We examined the effect of psychotic-like...
Psychological Medicine
March 5, 2018
Sagnik Bhattacharyya, Thomas T. J. Sainsbury, Paul Allen et al.
16 citations
BACKGROUND: Cannabis and its main psychoactive ingredient δ-9-tetrahydrocannibidiol (THC) can induce transient psychotic symptoms in healthy individuals and exacerbate them in those with established psychosis. However, not everyone experience these effects, suggesting that certain individuals are particularly susceptible. The neural basis of this sensitivity to the psychotomimetic effects of...
Acta Neuropsychiatrica
February 2018
Surapi Bhairavi Wijayendran, Aisling O'Neill, Sagnik Bhattacharyya
The relationship between cannabis use and the onset of psychosis is well established. Aberrant salience processing is widely thought to underpin many of these symptoms. Literature explicitly investigating the relationship between aberrant salience processing and cannabis use is scarce; with those few studies finding that acute tetrahydrocannabinol (THC) administration (the main psychoactive...
Scientific Reports
November 3, 2017
Sagnik Bhattacharyya, Alice Egerton, Euitae Kim et al.
Use of Cannabis, the most widely used illicit drug worldwide, is associated with acute anxiety, and anxiety disorders following regular use. The precise neural and receptor basis of these effects have not been tested in man. Employing a combination of functional MRI (fMRI) and positron emission tomography (PET), we investigated whether the effects of delta-9-tetrahydrocannabinol (delta-9-THC),...
The Lancet Psychiatry
July 10, 2017
Tabea Schoeler, Natalia Petros, Marta Di Forti et al.
142 citations
Background Cannabis use following the onset of first-episode psychosis has been linked to both increased risk of relapse and non-adherence with antipsychotic medication. Whether poor outcome associated with cannabis use is mediated through an adverse effect of cannabis on medication adherence is unclear. Methods In a prospective analysis of data acquired from four different adult inpatient and...
Current Addiction Reports
April 29, 2017
Marco Colizzi, Sagnik Bhattacharyya
Purpose of ReviewThe lack of clarity about the effect of cannabis use on cognition may be attributable to the considerable heterogeneity among studies in terms of cannabis composition. This article selectively reviews studies examining the distinctive effects of cannabinoids on human cognition, particularly those of delta-9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD).Recent...
The Lancet Psychiatry
October 1, 2016
Tabea Schoeler, Natalia Petros, Marta Di Forti et al.
BACKGROUND Although cannabis use after a first episode of psychosis has been associated with relapse, little is known about the determinants of this most preventable risk factor for relapse of psychosis. Here we aimed to study whether the effects on outcome vary depending on the type of cannabis consumed and usage pattern. METHODS In this observational study, we prospectively recruited and...
JAMA Psychiatry
September 28, 2016
Tabea Schoeler, Natalia Petros, Marta Di Forti et al.
106 citations
IMPORTANCE: Cannabis use after first-episode psychosis is associated with poor outcomes, but the causal nature of this association is unclear. OBJECTIVE: To examine the precise nature of the association between continued cannabis use after the onset of psychosis and risk of relapse of psychosis. DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study followed up for at least 2 years...
The Lancet Psychiatry
March 1, 2016
Tabea Schoeler, Anna Monk, Musa Sami et al.
BACKGROUND Although the link between cannabis use and development of psychosis is well established, less is known about the effect of continued versus discontinued cannabis use after the onset of psychosis. We aimed to summarise available evidence focusing on the relationship between continued and discontinued cannabis use after onset of psychosis and its relapse. METHODS In this systematic...