Cannabis use affects cortico-striatal networks that are essential for producing movement. In this review, we summarize the literature on motor system dysfunction in cannabis users and provide a rationale for why motor learning should be considered an important area in cannabis research. A majority of studies have addressed cognitive impairments in cannabis users and some have focused on driving...
Cannabidiol (CBD), a constituent of cannabis with few psychoactive effects, has been reported in some studies to attenuate certain aspects of Δ(9)-tetrahydrocannabinol (THC) intoxication. However, most studies have tested only one dose of CBD in combination with one dose of oral THC, making it difficult to assess the nature of this interaction. Further, the effect of oral CBD on smoked cannabis...
Cannabis sativa L. is one of the most popular psychoactive plants in our days. It is widely used as a medicine, a recreational drug and also as an entheogen. Archaeological findings suggest that the hemp plant was known in China as early as the 5th millennium B.C. The first written source documenting the use of cannabis as a drug is from a much later period and dates back to the 5th century...
Cannabis use history as predictor of neurocognitive response to cannabis intoxication remains subject to scientific and policy debates. The present study assessed the influence of cannabis on neurocognition in cannabis users whose cannabis use history ranged from infrequent to daily use. Drug users (N = 122) received acute doses of cannabis (300 μg/kg THC), cocaine HCl (300 mg) and placebo....
Recently, the anti-addictive potential of ayahuasca, a dimethyltryptamine(DMT)- and β-carboline-rich hallucinogenic beverage traditionally used by indigenous groups of the Northwest Amazon and currently by syncretic churches worldwide, has received increased attention. To better evaluate this topic, we performed a systematic literature review using the PubMed database to find quantitative...
Objetivo: revisar a literatura sobre a associação entre uso de cannabis e o desenvolvimento de esquizofrenia. Metodologia: revisão sistemática da literatura realizada em bases de dados eletrônicas (PubMed e SciELO), que inclui revisões e estudos observacionais (estudos de coorte e cortes transversais) publicados no período de janeiro de 2000 a novembro de 2015, além de estudos encontrados...
Novel cannabinoid compounds continue to be marketed as "legal" marijuana substitutes, even though little is known about their molecular and behavioral effects. Six of these compounds (ADBICA, ADB-PINACA, THJ-2201, RCS-4, JWH-122, JWH-210) were tested for in vitro and in vivo cannabinoid-like effects to determine their abuse liability. Binding to and functional activity at CB1 cannabinoid...
Cannabis or marijuana is an illegal drug that is being used mostly by young adultscan have adverse effects i.e., dependence syndrome, impaired respiratory and cardiovascularfunctions, psychosocial and mental health disorders. Objective: The present study examinedthe effects of cannabis (including bhang & charas) consumption on emotional and cognitivedisturbances and depressive symptoms in young...
In pre-clinical models of marijuana abuse, there is relatively limited evidence of delta-9-tetrahydrocannabinol's (THC) rewarding effects, as indexed by its general inability to induce a place preference. One explanation for this failure is that its rewarding effects are masked by its concurrently occurring aversive properties. Consistent with this explanation, THC pre-exposure, which...
Associations between cannabis use and psychotic outcomes are consistently reported, but establishing causality from observational designs can be problematic. We review the evidence from longitudinal studies that have examined this relationship and discuss the epidemiologic evidence for and against interpreting the findings as causal. We also review the evidence identifying groups at...
Cannabis use has been reported to increase the risk of developing schizophrenia and to worsen symptoms of the illness. Both of these outcomes might be attributable to the disruption by cannabis of the endogenous cannabinoid system's spatiotemporal regulation of the inhibitory circuitry in the prefrontal cortex that is essential for core cognitive processes, such as working memory, which are...
Rationale Δ 9 ‐Tetrahydrocannabinol (THC) produces both aversive and rewarding effects in animal models. Given that the balance between a drug's affective properties is thought to underlie its abuse potential, it is important to consider these properties of THC and how they (and their balance) are impacted by various factors. In this context, previous studies have examined the effect of THC...
Some of the most compelling evidence supporting an association between cannabinoid agonists and psychosis comes from controlled laboratory studies in humans. Randomized, double-blind, placebo-controlled, crossover laboratory studies demonstrate that cannabinoid agonists, including phytocannabinoids and synthetic cannabinoids, produce a wide range of positive, negative, and cognitive symptoms...
Heavy cannabis use is associated with reduced motivation. The basal ganglia, central in the motivation system, have the brain's highest cannabinoid receptor density. The frontal lobe is functionally coupled to the basal ganglia via segregated frontal-subcortical circuits conveying information from internal, self-generated activity. The basal ganglia, however, receive additional influence from...
BACKGROUND Although the link between cannabis use and development of psychosis is well established, less is known about the effect of continued versus discontinued cannabis use after the onset of psychosis. We aimed to summarise available evidence focusing on the relationship between continued and discontinued cannabis use after onset of psychosis and its relapse. METHODS In this systematic...
Previous studies have reported that peer groups are one of the most important predictors of adolescent and young adult marijuana use, and yet the neural correlates of social processing in marijuana users have not yet been studied. In the current study, marijuana-using young adults (n = 20) and non-using controls (n = 22) participated in a neuroimaging social exclusion task called Cyberball, a...
IntroductionDespite recent findings pointing toward cannabis psychosis as one area where gender differences may exist, there has been a widespread lack of attention paid to gender as a determinant of health in both psychiatric services and within the field of addiction.ObjectivesTo explore gender differences in treatment presentations for people with cannabis psychosis.AimsTo use national data...
Long-term heavy cannabis users (cannabis users) who are not acutely intoxicated have diminished subconscious neural responsiveness to affective stimuli. This study sought to determine if abnormal processing extends to the conscious evaluation of emotional stimuli. Functional magnetic resonance imaging (fMRI) was used to examine brain activity as cannabis users (N = 16) and non-cannabis-using...
Prolonged heavy exposure to cannabis is associated with impaired cognition and brain functional and structural alterations. We recently reported attenuated mismatch negativity (MMN) and altered P50 sensory gating in chronic cannabis users. This study investigated the extent of brain functional recovery (indexed by MMN and P50) in chronic users after cessation of use. Eighteen ex-users (median...
Smoking cannabis daily doubles an individual's risk of developing a psychotic disorder, yet indicators of specific vulnerability have proved largely elusive. Genetic variation is one potential risk modifier. Single-nucleotide polymorphisms in the AKT1 and catechol-O-methyltransferase (COMT) genes have been implicated in the interaction between cannabis, psychosis and cognition, but no studies...