Neuropsychopharmacology
December 8, 2010
Disruption of frontal θ coherence by Δ9-tetrahydrocannabinol is associated with positive psychotic symptoms.
European Journal of Pharmacology
December 1, 2010
Torbjörn U C Järbe, Roger S Gifford, Alexandros Makriyannis
The objective was to examine the time course of the cannabinoid 1 receptor antagonist/inverse agonist rimonabant's ability to antagonize in vivo cannabinergic agonist effects. We used two behavioral procedures sensitive to the effects of ∆⁹-tetrahydrocannabinol (∆⁹-THC): rat drug discrimination (EXP-1) and suppression of fixed-ratio responding (FR) for food reinforcement (EXP-2). Two training...
Psychopharmacology
December 2010
Robert A Battisti, Steven Roodenrys, Stuart J Johnstone et al.
Chronic cannabis use has been related to deficits in cognition (particularly memory) and the normal functioning of brain structures sensitive to cannabinoids. There is increasing evidence that conflict monitoring and resolution processes (i.e. the ability to detect and respond to change) may be affected. This study examined the ability to inhibit an automatic reading response in order to...
Pharmacology, Biochemistry, and Behavior
November 24, 2010
Michael E. Ballard, Harriet de Wit
Rationale: Previous studies examining the combined effects of ethanol and cannabis, or its primary psychoactive ingredient, ∆⁹-tetrahydrocannabinol (THC), have provided mixed results. Data from an in vitro study suggests that combined, sub-threshold doses of these drugs may interact to produce synergistic effects. Very low doses of the two drugs in combination have not been tested in humans....
Neuroscience
November 24, 2010
K H S Yang, D Isaev, M Morales et al.
The effects of Δ(9)-tetrahydrocannabinol (THC), the psychoactive component of cannabis, on the function of 5-HT type 3 (5-HT(3)) receptors were investigated using a two-electrode voltage clamp technique in Xenopus oocytes, and a whole-cell patch clamp technique in rat nodose ganglion neurons. In oocytes injected with 3 ng cRNA of 5-HT(3A) receptor, THC reversibly inhibited currents evoked with...
Addictive Behaviors
November 2010
Karen L. Hanson, Jennifer L Winward, Alecia D Schweinsburg et al.
Cognitive deficits that persist up to a month have been detected among adult marijuana users, but decrements and their pattern of recovery are less known in adolescent users. Previously, we reported cognitive deficits among adolescent marijuana users after one month of abstinence (Medina, Hanson, Schweinsburg, Cohen-Zion, Nagel, & Tapert, 2007). In this longitudinal study, we characterized...
Accident; Analysis and Prevention
November 2010
Adi Ronen, Hadas Schwartz Chassidim, Pnina Gershon et al.
Driving under the influence of drugs (DUID) is one of the main causes of car accidents. Alcohol and marijuana are the most popular drugs among recreational users. Many classify these drugs as "Light" drugs and therefore allow themselves to drive after consuming them. The study had two main objectives: 1) to investigate the effect of alcohol (BAC=0.05%), THC (13 mg) and their combination on...
Progress in Neurobiology
November 2010
Matthijs G. Bossong, Raymond J.m. Niesink
Cannabis use during adolescence increases the risk of developing psychotic disorders later in life. However, the neurobiological processes underlying this relationship are unknown. This review reports the results of a literature search comprising various neurobiological disciplines, ultimately converging into a model that might explain the neurobiology of cannabis-induced schizophrenia. The...
Schizophrenia Research
October 30, 2010
Michael T Compton, Beth Broussard, Claire E. Ramsay et al.
Introduction Limited research indicates that pre-illness cannabis use may result in an earlier age at onset of psychosis, though little is known about the influence of prior cannabis use on the premorbid and prodromal phases. This study examined effects of prior or concurrent cannabis (as well as nicotine and alcohol) use on: (1) early adolescent (12–15 years) premorbid functioning, (2) late...
Psychopharmacology
October 30, 2010
Johannes G. Ramaekers, Eef L. Theunissen, Marjolein de Brouwer et al.
168 citations
INTRODUCTION: Previous research has shown that heavy cannabis users develop tolerance to the impairing effects of Δ9-tetrahydrocannabinol (THC) on neurocognitive functions. Animal studies suggest that chronic cannabis consumption may also produce cross-tolerance for the impairing effects of alcohol, but supportive data in humans is scarce. PURPOSE: The present study was designed to assess...
Neuropsychopharmacology
October 2010
Colm M P O'Tuathaigh, Magdalena Hryniewiecka, Aine Behan et al.
Cannabis use confers a two-fold increase in the risk for psychosis, with adolescent use conferring even greater risk. A high-low activity catechol-O-methyltransferase (COMT) polymorphism may modulate the effects of adolescent Δ-9-tetrahydrocannabinol (THC) exposure on the risk for adult psychosis. Mice with knockout of the COMT gene were treated chronically with THC (4.0 and 8.0 mg/kg over 20...
The British Journal of Psychiatry
October 2010
Celia J. A. Morgan, Gráinne Schäfer, Tom P. Freeman et al.
The two main constituents of cannabis, cannabidiol and Δ(9)-tetrahydrocannabinol (THC), have opposing effects both pharmacologically and behaviourally when administered in the laboratory. Street cannabis is known to contain varying levels of each cannabinoid. To study how the varying levels of cannabidiol and THC have an impact on the acute effects of the drug in naturalistic settings. Cannabis...
The British Journal of Psychiatry
September 30, 2010
Cécile Henquet, Rebecca Kuepper
16 citations
A recent study by Morgan and colleagues found that cannabidiol attenuates the acute cognitive effects of delta-9-tetrahydrocannabinol (THC). This is of interest as THC has been associated with the detrimental effects of cannabis on mental health in at-risk users, and the potency of cannabis is increasing across Europe.
Harm Reduction Journal
September 28, 2010
Anna Buadze, Rudolf Stohler, Beate Schulze et al.
There has been a considerable amount of debate among the research community whether cannabis use may cause schizophrenia and whether cannabis use of patients with schizophrenia is associated with earlier and more frequent relapses. Considering that studies exploring patients' view on controversial topics have contributed to our understanding of important clinical issues, it is surprising how...
Journal of Psychopharmacology
September 3, 2010
Gjh Dumont, J. G. Coen van Hasselt, M. de Kam et al.
38 citations
In Western societies a considerable percentage of young people expose themselves to the combination of 3,4-methylenedioxymethamphetamine (MDMA or ‘ecstasy’) and cannabis. The aim of the present study was to assess the acute effects of co-administration of MDMA and THC (the main psychoactive compound of cannabis) on pharmacokinetics, psychomotor performance, memory and subjective experience over...
Journal of Psychoactive Drugs
September 2010
Alecia Dager Schweinsburg, Brian C Schweinsburg, Krista Lisdahl Medina et al.
Some neurocognitive recovery occurs within a month of abstinence from heavy marijuana use, yet functional magnetic resonance imaging (fMRI) has revealed altered activation among recent and abstinent adult users. We compared fMRI response during a spatial working memory (SWM) task between adolescent marijuana users with brief and sustained durations of abstinence. Participants were 13 recent...
European Archives of Psychiatry and Clinical Neuroscience
September 2010
Patrik Roser, Beate Della, Christine Norra et al.
Mismatch negativity (MMN) is an auditory event-related potential indicating auditory sensory memory and information processing. The present study tested the hypothesis that chronic cannabis use is associated with deficient MMN generation. MMN was investigated in age- and gender-matched chronic cannabis users (n = 30) and nonuser controls (n = 30). The cannabis users were divided into two groups...
Substance Use & Misuse
September 2010
Valentina Lorenzetti, Dan I Lubman, Sarah Whittle et al.
In animal studies, tetrahydrocannabinol (THC) has been found to affect brain morphology, particularly within areas rich in cannabinoid receptors (e.g., hippocampus, cerebral cortex). While cannabis remains the most widely used illicit drug worldwide, there has been limited work investigating its effects on human brain tissue. In this paper, we conducted a systematic review of existing...
Pharmacology, Biochemistry, and Behavior
September 2010
Carl L. Hart, Aaron B Ilan, Alan Gevins et al.
Previously, we reported that acute marijuana intoxication minimally affected complex cognitive performance of daily marijuana smokers. It is possible that the cognitive tests used were insensitive to marijuana-related cognitive effects. In the current study, electroencephalographic (EEG) signals were recorded as daily marijuana users performed additional tests of immediate working memory and...
Neuroimage
August 15, 2010
Gloria M P Roberts, Hugh P Garavan
Evidence suggests that users of ecstasy (3,4-methylenedioxymethamphetamine) have behavioural and cognitive deficits and show increased impulsivity. Impulse control impairments have been shown to be common to a number of addictive behaviours and may constitute a risk factor for drug abuse and dependence. The aim of this study was to investigate brain activation during response inhibition and...