Journal of Neuroscience
December 7, 2011
George R King, Thomas Ernst, Weiran Deng et al.
Cannabis is the most abused illegal substance in the United States. Alterations in brain function and motor behavior have been reported in chronic cannabis users, but the results have been variable. The current study aimed to determine whether chronic active cannabis use in humans may alter psychomotor function, brain activation, and hypothalamic-pituitary-axis (HPA) function in men and women....
Neuropharmacology
December 2011
Erica Y Shen, Syed F. Ali, Jerrold S. Meyer
Most recreational users of 3, 4-methylenedioxymethamphetamine (MDMA or "ecstasy") also take cannabis, in part because cannabis can reduce the dysphoric symptoms of the ecstasy come-down such as agitation and insomnia. Although previous animal studies have examined the acute effects of co-administering MDMA and Δ(9)-tetrahydrocannabinol (THC), which is the major psychoactive ingredient in...
Psychopharmacology
November 2011
Charlotte Klein, Emily Karanges, Adena Spiro et al.
The interactions between Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) during chronic treatment, and at equivalent doses, are not well characterised in animal models. The aim of this study is to examine whether the behavioural effects of THC, and blood and brain THC levels are affected by pre-treatment with equivalent CBD doses. Adolescent rats were treated with ascending daily THC...
Psychological Medicine
November 1, 2011
J E Houston, J Murphy, M Shevlin et al.
Cannabis consumption continues to be identified as a causal agent in the onset and development of psychosis. However, recent findings have shown that the effect of cannabis on psychosis may be moderated by childhood traumatic experiences. Using hierarchical multivariate logistic analyses the current study examined both the independent effect of cannabis consumption on psychosis diagnosis and...
Schizophrenia Bulletin
October 29, 2011
Christine Barrowclough, Richard A Emsley, Emily Eisner et al.
33 citations
BACKGROUND: Cannabis use has been identified as a potent predictor of the earlier onset of psychosis, but meta-analysis has not indicated that it has a clear effect in established psychosis. AIM: To assess the association between cannabis and outcomes, including whether change in cannabis use affects symptoms and functioning, in a large sample of people with established nonaffective psychosis...
Behavioural Brain Research
October 10, 2011
A Galanopoulos, Alexia Polissidis, Z Papadopoulou-Daifoti et al.
Endocannabinoids are involved in excitatory neurotransmission initiated by glutamate and aspartate. The aim of the present study was to investigate the effects of the cannabinoid agonists, Δ(9)-THC and WIN55,212-2, on tissue (prefrontal cortex, dorsal striatum, nucleus accumbens, hippocampus, amygdala and hypothalamus) levels of glutamate and aspartate in two rat phenotypes, high responders...
Psychopharmacology
October 5, 2011
Eef L. Theunissen, Gerold F. Kauert, Stefan W. Toennes et al.
82 citations
RATIONALE: Experienced cannabis users demonstrate tolerance to some of the impairing acute effects of cannabis. OBJECTIVES: The present study investigates whether event-related potentials (ERPs) differ between occasional and heavy cannabis users after acute Δ9-tetrahydrocannabinol (THC) administration, as a result of tolerance. METHODS: Twelve occasional and 12 heavy cannabis users participated...
Psychopharmacology
October 2011
Laura E Wise, Stephen A Varvel, Dana E Selley et al.
Cannabis users display a constellation of withdrawal symptoms upon drug discontinuation, including sleep disturbances, irritability, and possibly memory deficits. In cannabinoid-dependent rodents, the CB(1) antagonist rimonabant precipitates somatic withdrawal and enhances forskolin-stimulated adenylyl cyclase activity in cerebellum, an effect opposite that of acutely administered...
Journal of Clinical Psychopharmacology
October 2011
David A. Gorelick, Robert S. Goodwin, Eugene Schwilke et al.
Cannabinoid CB1 receptor antagonists have potential therapeutic benefits, but antagonist-elicited cannabis withdrawal has not been reported in humans. Ten male daily cannabis smokers received 8 days of increasingly frequent 20-mg oral Δ⁹-tetrahydrocannabinol (THC) dosages (40-120 mg/d) around-the-clock to standardize cannabis dependence while residing on a closed research unit. On the ninth...
Psychological Medicine
October 1, 2011
Rebecca Kuepper, Jim van Os, Roselind Lieb et al.
BackgroundCannabis use is considered a component cause of psychotic illness, interacting with genetic and other environmental risk factors. Little is known, however, about these putative interactions. The present study investigated whether an urban environment plays a role in moderating the effects of adolescent cannabis use on psychosis risk.MethodProspective data (n=1923, aged 14–24 years at...
Drug and Alcohol Dependence
September 14, 2011
J. Grant, S. Chamberlain, Liana R. N. Schreiber et al.
Background Cannabis is the most widely used illicit substance and has been associated with cognitive impairment. It is unclear whether such impairment can occur in the absence of potential confounding influences of co-morbid axis-I disorders and use of other illicit substances. Method Young adult volunteers (18–29 years) were recruited from the general community on the basis of having no axis-I...
The British Journal of Psychiatry
September 9, 2011
Killian A. Welch, Andrew C. Stanfield, Andrew Mark McIntosh et al.
43 citations
BACKGROUND: No longitudinal study has yet examined the association between substance use and brain volume changes in a population at high risk of schizophrenia. AIMS: To examine the effects of cannabis on longitudinal thalamus and amygdala-hippocampal complex volumes within a population at high risk of schizophrenia. METHOD: Magnetic resonance imaging scans were obtained from individuals at...
Human Psychopharmacology Clinical and Experimental
September 7, 2011
Philip N. Murphy, Philip G. Erwin, L. Maciver et al.
9 citations
This study aimed to examine the relationship between the consumption of ecstasy (3,4-methylenedioxymethamphetamine (MDMA)) and cannabis, and performance on the random letter generation task which generates dependent variables drawing upon executive inhibition and access to semantic long-term memory (LTM). The participant group was a between-participant independent variable with users of both...
Journal of Psychopharmacology
September 2, 2011
Paul R A Stokes, Alice Egerton, Ben Watson et al.
62 citations
Cannabis use in adolescence is emerging as a risk factor for the development of psychosis. In animal studies, Δ9-tetrahydrocannabinol (THC), the psychoactive component of cannabis, modulates striatal dopaminergic neurotransmission. Alterations in human striatal dopaminergic function have also been reported both in psychosis and in stimulant use. We sought to examine whether striatal dopamine...
International Clinical Psychopharmacology
September 1, 2011
Bárbara Arias, Mar Fatjó‐Vilas, Gemma Estrada et al.
The 15th Biennial Winter Workshop in Psychoses, 15–18 November 2009, Barcelona, Spain: DRUG INDUCED PSYCHOSES
Expert Opinion on Drug Safety
September 2011
Philip Robson
There is a growing consensus that cannabis dependence is a substantial and underappreciated problem. The key component responsible for the euphoric effects of cannabis and its dependence potential is δ-9-tetrahydrocannabinol (THC). THC-containing cannabinoid medicines theoretically pose a risk of abuse and dependence. In order to evaluate the potential of Sativex to cause cannabis-like...
Behavioural Pharmacology
September 2011
Jenny L Wiley, D Matthew Walentiny, Robert E Vann et al.
Δ(9)-Tetrahydrocannabinol (THC) discrimination in rodents is a behavioral assay that has been used to probe differences among classes of cannabinoids in rats. The purpose of this study was to determine whether traditional and anandamide-like cannabinoids were distinguishable in cannabinoid discrimination procedures in mice. Male mice were trained to discriminate 30 mg/kg THC or 70 mg/kg...
Behavioural Pharmacology
September 2011
Alexa A Wakley, Rebecca M Craft
This study examined cannabinoid-opioid interactions within the same subjects on measures of discrimination, antinociception, horizontal locomotion, and catalepsy. Male Sprague-Dawley rats were trained to discriminate Δ(9)-tetrahydrocannabinol (THC, 3 mg/kg) from vehicle. THC alone (0.32-10 mg/kg) dose-dependently increased THC-appropriate lever responding and decreased response rate. THC alone...
Journal of Neurochemistry
September 2011
Catalin M Filipeanu, Jesse J Guidry, Stuart T Leonard et al.
To characterize the long-term effects of adolescent marijuana abuse, we performed a proteomic analysis of cerebellar extracts from adult female rats with and without ovariectomy that were treated with Δ9-THC for 40 days during adolescence. Six proteins were found to significantly differ among the four treatment groups, with Δ9-THC and ovariectomy (OVX) decreasing the mitochondrial proteins,...
Behavioural Pharmacology
September 2011
Torbjörn U C Järbe, Hongfen Deng, Subramanian K Vadivel et al.
We examined four different cannabinergic aminoalkylindole ligands, including one drug (AM678=JWH018) found in herbal 'Spice' concoctions, for their ability to substitute for Δ(9)-tetrahydrocannabinol (THC), and the ability of the cannabinoid receptor 1-selective antagonist/inverse agonist rimonabant to block the substitution, 30 and 90 min after intraperitoneal injection. Rats trained to...