Brain Imaging and Behavior
December 14, 2015
Johannes G. Ramaekers, J. H. van Wel, Desirée Spronk et al.
61 citations
The dopamine β-hydroxylase (DβH) enzyme transforms dopamine into noradrenaline. We hypothesized that individuals with low activity DBH genotypes (rs1611115 CT/TT) are more sensitive to the influence of cannabis and cocaine on cognitive impulse control and functional connectivity in the limbic 'reward' circuit because they experience a drug induced hyperdopaminergic state compared to individuals...
Brain Research
December 2, 2015
Dan P Covey, Jennifer M Wenzel, Joseph Cheer
Marijuana is the most popular illegal drug worldwide. Recent trends indicate that this may soon change; not due to decreased marijuana use, but to an amendment in marijuana's illegal status. The cannabinoid type 1 (CB1) receptor mediates marijuana's psychoactive and reinforcing properties. CB1 receptors are also part of the brain endocannabinoid (eCB) system and support numerous forms of...
Multiple Sclerosis Journal
December 1, 2015
Anthony Feinstein, Emma Banwell, Bennis Pavisian
Given data showing that cannabis (herbal drug from the Cannabis sativa plant) can impair cognition in healthy subjects, the possibility that it may also do so in people with multiple sclerosis (MS) should be cause for concern. Approximately 20% of people with MS inhale or ingest cannabis for a variety of symptoms, or as a lifestyle choice. In addition, pharmaceutically manufactured cannabis (in...
Developmental Cognitive Neuroscience
December 2015
Kelly A. Sagar, M K Dahlgren, A Gönenç et al.
Marijuana (MJ) use is on the rise, particularly among teens and emerging adults. This poses serious public health concern, given the potential deleterious effects of MJ on the developing brain. We examined 50 chronic MJ smokers divided into early onset (regular MJ use prior to age 16; n=24) and late onset (age 16 or later; n=26), and 34 healthy control participants (HCs). All completed a...
Brain Connectivity
December 2015
Daniel Kleinloog, Serge A.r.b. Rombouts, Remco Zoethout et al.
This analysis examines the neuronal foundation of drug-induced psychomimetic symptoms by relating the severity of these symptoms to changes in functional connectivity for a range of different psychoactive compounds with varying degrees of psychomimetic effects. The repeated measures design included 323 resting-state functional magnetic resonance imaging time series and measures of subjective...
Developmental Cognitive Neuroscience
December 2015
Joanna Jacobus, Lindsay M Squeglia, Alejandro D Meruelo et al.
Studies suggest marijuana impacts gray and white matter neural tissue development, however few prospective studies have determined the relationship between cortical thickness and cannabis use spanning adolescence to young adulthood. This study aimed to understand how heavy marijuana use influences cortical thickness trajectories across adolescence. Subjects were adolescents with heavy marijuana...
Neuropsychopharmacology
December 2015
Corey T Watson, Henrietta Szutorisz, Paras Garg et al.
Drug exposure during critical periods of development is known to have lasting effects, increasing one's risk for developing mental health disorders. Emerging evidence has also indicated the possibility for drug exposure to even impact subsequent generations. Our previous work demonstrated that adolescent exposure to Δ(9)-tetrahydrocannabinol (THC), the main psychoactive component of marijuana...
Developmental Cognitive Neuroscience
December 2015
Skyler G Shollenbarger, Jenessa Price, Jon Wieser et al.
Regions undergoing maturation with CB1 receptors may be at increased risk for cannabis-induced alterations. Here, we examine the relationships between cannabis use and prefrontal (PFC) and inferior parietal gyrification and surface area (SA) in youth. Participants included 33 cannabis users and 35 controls (ages 18-25). Exclusions included co-morbid psychiatric/neurologic disorders and heavy...
European Neuropsychopharmacology
December 2015
Erica Zamberletti, Marina Gabaglio, Pamela Prini et al.
Over 180 million people consume cannabis globally. Cannabis use peaks during adolescence with a trend for continued consumption by adults. Notably, several studies have shown that long-term and heavy cannabis use during adolescence can impair brain maturation and predispose to neurodevelopmental disorders, although the neurobiological mechanisms underlying this association remain largely...
Developmental Cognitive Neuroscience
December 2015
Francesca Filbey, Tim McQueeny, Samuel J DeWitt et al.
As the most commonly used illicit substance during early adolescence, long-term or latent effects of early adolescent marijuana use across adolescent developmental processes remain to be determined. We examined cortical thickness, gray/white matter border contrast (GWR) and local gyrification index (LGI) in 42 marijuana (MJ) users. Voxelwise regressions assessed early-onset (age <16) vs....
Developmental Cognitive Neuroscience
December 2015
Mary P. Becker, Paul F Collins, Kelvin O Lim et al.
Diffusion tensor imaging (DTI) studies of cannabis users report alterations in brain white matter microstructure, primarily based on cross-sectional research, and etiology of the alterations remains unclear. We report findings from longitudinal voxelwise analyses of DTI data collected at baseline and at a 2-year follow-up on 23 young adult (18-20 years old at baseline) regular cannabis users...
Annals of General Psychiatry
December 1, 2015
Samuel Sarrazin, Florence Louppe, Raphaël Doukhan et al.
6 citations
BACKGROUND: A high prevalence of cannabis use disorder has been reported in subjects suffering from schizophrenia, fuelling intense debate about whether schizophrenia with pre-onset cannabis use disorder may be a distinct entity with specific features or whether cannabis use disorder can precipitate schizophrenia in genetically vulnerable subjects. METHODS: We retrospectively assessed...
Pharmacological Research
December 2015
S Tai, William S Hyatt, C Gu et al.
These studies probed the relationship between intrinsic efficacy and tolerance/cross-tolerance between ∆(9)-THC and synthetic cannabinoid drugs of abuse (SCBs) by examining in vivo effects and cellular changes concomitant with their repeated administration in mice. Dose-effect relationships for hypothermic effects were determined in order to confirm that SCBs JWH-018 and JWH-073 are higher...
Journal of Medical Toxicology
December 1, 2015
Adebisi I Obafemi, Kurt Kleinschmidt, Collin Goto et al.
Synthetic cannabinoid receptor agonists (SCRAs) are emerging designer drugs of abuse. Most reports on the health effects of these drugs are case reports. Unlike SCRAs, marijuana has classically been used via many routes of exposure including oral, such as in brownies. We report on 11 symptomatic patients who unknowingly ingested brownies laced with analytically confirmed SCRA and presented with...
Psychiatry Research
November 25, 2015
L. Buchy, L. Seidman, Kristin Cadenhead et al.
Among people with psychosis, those with a history of cannabis use show better cognitive performance than those who are cannabis naïve. It is unknown whether this pattern is present in youth at clinical high risk (CHR) of psychosis. We evaluated relationships between IQ and cannabis use while controlling for use of other substances known to impact cognition in 678 CHR and 263 healthy control...
Journal of Ethnopharmacology
November 4, 2015
Baudry N Nsuala, Gill Enslin, Alvaro Viljoen
Leonotis leonurus, locally commonly known as "wilde dagga" (=wild cannabis), is traditionally used as a decoction, both topically and orally, in the treatment of a wide variety of conditions such as haemorrhoids, eczema, skin rashes, boils, itching, muscular cramps, headache, epilepsy, chest infections, constipation, spider and snake bites. The dried leaves and flowers are also smoked to...
European Neuropsychopharmacology
November 2015
Mikael A Kowal, Henk Van Steenbergen, Lorenza S. Colzato et al.
Cannabis has been suggested to impair the capacity to recognize discrepancies between expected and executed actions. However, there is a lack of conclusive evidence regarding the acute impact of cannabis on the neural correlates of error monitoring. In order to contribute to the available knowledge, we used a randomized, double-blind, between-groups design to investigate the impact of...
Behavioural Brain Research
October 15, 2015
Francesca Filbey, Tim McQueeny, Shrinath Kadamangudi et al.
Combined use of marijuana (MJ) and tobacco is highly prevalent in today's population. Individual use of either substance is linked to structural brain changes and altered cognitive function, especially with consistent reports of hippocampal volume deficits and poorer memory performance. However, the combined effects of MJ and tobacco on hippocampal structure and on learning and memory processes...
Substance Abuse
October 1, 2015
Kara S. Bagot, Robert Milin, Yifrah Kaminer
Background: It is important to evaluate the impact of cannabis use on onset and course of psychotic illness, as the increasing number of novice cannabis users may translate into a greater public health burden. This study aims to examine the relationship between adolescent onset of regular marijuana use and age of onset of prodromal symptoms, or first episode psychosis, and the manifestation of...
Neurobiology of Disease
October 2015
Michael D Ballinger, Atsushi Saito, Bagrat Abazyan et al.
Cannabis is an increasingly popular and controversial drug used worldwide. Cannabis use often begins during adolescence, a highly susceptible period for environmental stimuli to alter functional and structural organization of the developing brain. Given that adolescence is a critical time for the emergence of mental illnesses before full-onset in early adulthood, it is particularly important to...