Neuroimage
May 6, 2010
Paul R A Stokes, Alice Egerton, Ben Watson et al.
Delta9-tetrahydrocannabinol (THC) increases prefrontal cortical dopamine release in animals, but this is yet to be examined in humans. In man, striatal dopamine release can be indexed using [11C]-raclopride positron emission tomography (PET), and recent reports suggest that cortical [11C]-raclopride binding may also be sensitive to dopaminergic challenges. Using an existing dataset we examined...
Journal of Psychopharmacology
May 2010
S Fokos, G Panagis
Although cannabis derivatives produce clear subjective motivational responses in humans leading to drug-seeking behaviour, the reinforcing attributes of these subjective effects are difficult to define in experimental animals. The aim of this study was to examine how exposure to chronic unpredictable stress (CUS) will affect reward function and anxiety after acute administration of...
Drug and Alcohol Review
May 1, 2010
Silvia Minozzi, Marina Davoli, Anna Maria Bargagli et al.
80 citations
ISSUES: Cross-sectional surveys have revealed that cannabis is the most widely used illicit substance in Western countries. Cannabis intoxication can lead to acute, transient psychotic symptoms and the short-term exacerbation of pre-existing psychotic symptoms. However, controversy exists about whether cannabis can actually cause long-term psychosis. APPROACH: We summarised the findings of...
Psychopharmacology
May 2010
Robert A Battisti, Steven Roodenrys, Stuart J Johnstone et al.
The endogenous cannabinoid system is sensitive to the introduction of exogenous cannabinoids such as delta-9-tetrahydrocannabinol, which are known to impact upon memory functioning. We sought to examine the impact of chronic cannabis use upon memory-related brain function via examination of the subsequent memory effect (SME) of the event-related potential (ERP). The SME is predictive of recall...
Journal of the American Academy of Child and Adolescent Psychiatry
April 14, 2010
Gerry Jager, Robert I Block, Maartje Luijten et al.
Objective: Early-onset cannabis use has been associated with later use/abuse, mental health problems (psychosis, depression), and abnormal development of cognition and brain function. During adolescence, ongoing neurodevelopmental maturation and experience shape the neural circuitry underlying complex cognitive functions such as memory and executive control. Prefrontal and temporal regions are...
Psychopharmacology
April 2010
Marcello Solinas, Gianluigi Tanda, Carrie E Wertheim et al.
Although delta-9-tetreahydrocannabinol (THC)-induced elevations in accumbal dopamine levels are believed to play an important role in the abuse-related effects of cannabis, little direct evidence has been provided that the dopaminergic system is involved in the psychotropic effects of THC. The objective of this study is to investigate whether drugs activating or blocking the dopaminergic system...
Journal of Psychopharmacology
March 2010
Lineke Zuurman, Christine Roy, R C Schoemaker et al.
CB1 antagonists such as AVE1625 are potentially useful in the treatment of obesity, smoking cessation and cognitive impairment. Proof of pharmacological action of AVE1625 in the brain can be given by antagonising the effects of delta-9-tetrahydrocannabinol (THC), a CB1/CB2 agonist. Inhibition of THC-induced effects by AVE1625 was observed on Visual Analogue Scales 'alertness', 'feeling high',...
Substance Use & Misuse
March 1, 2010
Ornella Corazza, Fabrizio Schifano
43 citations
Increase in recreational ketamine use may be a cause for concern. We aimed here at assessing, in a sample of ketamine misusers, concordance between the typical near-death experience (NDE) features and the on-drug psychoactive effects the subjects experienced. In 2003-2005, a sample of previous ketamine misusers recollecting a ketamine-related NDE were recruited through snowballing and screened...
Brazilian Journal of Psychiatry
March 1, 2010
Jaime E. C. Hallak, João Paulo Machado‐de‐Sousa, José Alexandre S. Crippa et al.
122 citations
OBJECTIVE: The last decade has seen increasing evidence of dysfunctions in the endogenous cannabinoid system in schizophrenia and of its relationship with the typical cognitive impairment of the disorder. Studies in animal models, healthy volunteers, and psychotic patients clearly suggest an antipsychotic-like effect of cannabidiol. This study investigated the effects of cannabidiol on...
The World Journal of Biological Psychiatry
March 1, 2010
Patrik Roser, Franz X. Vollenweider, Wolfram Kawohl
63 citations
Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the principal psychoactive constituent of the Cannabis sativa plant, and other agonists at the central cannabinoid (CB(1)) receptor may induce characteristic psychomotor effects, psychotic reactions and cognitive impairment resembling schizophrenia. These effects of Delta(9)-THC can be reduced in animal and human models of psychopathology by two...
PLoS One
February 10, 2010
Clara Touriño, Andreas Zimmer, Olga Valverde
55 citations
The majority of MDMA (ecstasy) recreational users also consume cannabis. Despite the rewarding effects that both drugs have, they induce several opposite pharmacological responses. MDMA causes hyperthermia, oxidative stress and neuronal damage, especially at warm ambient temperature. However, THC, the main psychoactive compound of cannabis, produces hypothermic, anti-inflammatory and...
Drug and Alcohol Dependence
February 9, 2010
Joanna S Zeiger, Brett C Haberstick, Robin P Corley et al.
Introduction: Marijuana is the most commonly used illicit drug among adolescents. Marijuana use induces both psychological and physiological responses, which can be interpreted by an individual in a variety of ways (i.e. subjective effects). We have examined subjective effects in adolescent, young adult community, and clinical populations to determine how patterns of use may be predicted by an...
Journal of Neurochemistry
February 2010
Ni Fan, Hongwei Yang, Jian Zhang et al.
Chronic use of marijuana impairs synaptic plasticity and cognitive function. However, the molecular mechanisms by which marijuana alters long-term synaptic plasticity are largely unknown. Here, we show that repeated in vivo exposures to Delta9-THC for 7 consecutive days significantly impaired hippocampal long-term potentiation (LTP) of excitatory glutamatergic synaptic transmission. The...
Behavioural Brain Research
January 20, 2010
Haitham Amal, Lilach Fridman-Rozevich, Roey Senn et al.
A single administration of an extremely low dose (0.002 mg/kg) of Delta9-tetrahydrocannabinol (THC; the psychoactive ingredient of marijuana) to ICR mice induced long-term cognitive deficits that lasted for at least 5 months. The behavioral deficits were detected by several tests that evaluated different aspects of memory and learning, including spatial navigation and spatial and non-spatial...
Pharmacology
2010
Matthew Goddard, Paul F Smith, John C Ashton
Previous studies have suggested panic induced by cannabinoids may be potentiated by concurrently using selective serotonin reuptake inhibitors. We therefore tested for panic and anxiety-related behaviour in rats coadministered with the selective serotonin reuptake inhibitor fluoxetine hydrochloride and the CB1 agonist delta9-tetrahydrocannabinol. Although each drug alone elicited behaviours...
Clinical Neuropharmacology
2010
Joshua A Lile, Thomas H Kelly, Lon R Hays
The central effects of Δ-tetrahydrocannabinol (Δ-THC), the primary active constituent of cannabis, are attributed to cannabinoid CB1 receptor activity, although clinical evidence is limited. Drug discrimination has proven useful for examining the neuropharmacology of drugs, as data are concordant with the actions of a drug at the receptor level. The aim of this study was to determine the...
The International journal on drug policy
2010
Jennifer McLaren, Edmund Silins, D. Hutchinson et al.
Over the past five years, the release of cohort studies assessing the link between cannabis and psychosis has increased attention on this relationship. Existing reviews generally conclude that these cohort studies show cannabis has a causal relationship to psychosis, or at least that one cannot be excluded. Few studies have evaluated the relative strengths and limitations of these...
European Psychiatry
2010
Andrea Fiorillo, D. Giacco, Mario Luciano et al.
Objectives: This study aimed to assess:a) the socio-demographic characteristics of patients with schizophrenia who were using cannabis at time of first appearing of psychotic symptoms; b) the impact of cannabis on the duration of untreated psychosis (DUP) and on pathways to care; c) the influence of cannabis on the clinical onset and on the first three years of the disorder. Methods: Twenty-two...
Neuropharmacology
2010
Nora Laaris, Cameron H Good, Carl R. Lupica
Marijuana impairs learning and memory through actions of its psychoactive constituent, delta-9-tetrahydrocannabinol (Delta(9)-THC), in the hippocampus, through activation of cannabinoid CB1 receptors (CB1R). CB1Rs are found on glutamate and GABA neuron axon terminals in the hippocampus where they control neurotransmitter release. Previous studies suggest that Delta(9)-THC is a partial agonist...
Neurotoxicology and Teratology
2010
Lauren C Harte, Diana Dow-Edwards
Research suggests that use and abuse of marijuana can be especially harmful if it occurs during adolescence, a period of vast developmental changes throughout the brain. We examined the effects of 2mg/kg (9)-tetrahydrocannabinol (THC) administered daily via intra-peritoneal injections during juvenile/early adolescence (postnatal day 22-40) or late adolescence (postnatal day 41-60) on locomotor...