Schizophrenia Research
May 1, 2015
Toby T Winton-Brown, V. Kumari, F. Windler et al.
Sensorimotor gating, measured as the modification of eye blink startle reflexes to loud acoustic stimuli by quieter preceding stimuli, is altered in those with psychosis, their relatives and those at high clinical risk for psychosis. Alterations have also been shown in cannabis users, albeit to a lesser extent, and cannabis is a known risk factor for the onset of psychosis in clinically and...
Journal of Psychopharmacology
October 5, 2012
Amir Englund, Paul D. Morrison, Judith Nottage et al.
463 citations
Community-based studies suggest that cannabis products that are high in Δ⁹-tetrahydrocannabinol (THC) but low in cannabidiol (CBD) are particularly hazardous for mental health. Laboratory-based studies are ideal for clarifying this issue because THC and CBD can be administered in pure form, under controlled conditions. In a between-subjects design, we tested the hypothesis that pre-treatment...
Psychological Medicine
October 2009
Paul D. Morrison, V Zois, D A McKeown et al.
Recent work suggests that heavy use of cannabis is associated with an increased risk of schizophrenia-like psychosis. However, there is a dearth of experimental studies of the effects of the constituents of cannabis, such as Delta9-tetrahydrocannabinol (THC). In a study of intravenous (i.v.) synthetic THC in healthy humans, we aimed to study the relationship of the psychotic symptoms induced by...
European Psychiatry
2009
Paul D. Morrison, Shitij Kapur, R. Murray
1 citation
It has long been known that cannabis can elicit an acute psychotic reaction. Recent work shows that, of the 60 cannabinoid molecules in the plant, delta-9-tetrahydrocannibinol is responsible for the central effects of cannabis. Here we aimed to investigate, in more detail, the psychological effects of synthetic intravenous THC in healthy subjects. Over 2 experimental sessions, participants...
Psychopharmacology
December 2005
Paul J Fletcher, Catherine C Tenn, Zoë Rizos et al.
Repeated exposure to psychomotor stimulants can lead to sensitization to their effects, and sensitization has been implicated in the pathophysiology of schizophrenia and drug abuse. These disorders are characterized by cognitive deficits, particularly in prefrontally mediated executive function. The present experiments were conducted to investigate the effects of sensitizing regimens of...
Schizophrenia Research
November 1, 2005
Shitij Kapur, Romina Mizrahi, Ming Li
510 citations
How does an excess in a neurochemical lead someone to being paranoid about the intentions of their neighbour? And why does blocking a dopamine receptor improve this symptom? In this article we present a heuristic framework which attempts to link the biology, phenomenology and pharmacology of psychosis. Focussing on dopamine's role in reward prediction and motivational salience we propose that...
American Journal of Psychiatry
2003
Shitij Kapur
2,813 citations
Objective: The clinical hallmark of schizophrenia is psychosis. The objective of this overview is to link the neurobiology (brain), the phenomenological experience (mind), and pharmacological aspects of psychosis-in-schizophrenia into a unitary framework. Method: Current ideas regarding the neurobiology and phenomenology of psychosis and schizophrenia, the role of dopamine, and the mechanism of...