Cannabis sativa, the most widely used illicit drug, has profound effects on levels of anxiety in animals and humans. Although recent studies have helped provide a better understanding of the neurofunctional correlates of these effects, indicating the involvement of the amygdala and cingulate cortex, their reciprocal influence is still mostly unknown. In this study dynamic causal modelling (DCM)...
Salvia divinorum is a naturally occurring psychedelic considered to be one of the most potent hallucinogens found to date. The few behavioral studies conducted conclude that Salvia's effects may be similar to traditional psychedelics, which is noteworthy because Salvia acts via a unique molecular mechanism as a kappa opioid receptor agonist. One hundred and ninety-three participants, including...
While Delta(9)-tetrahydrocannabinol (THC) is the main psychoactive constituent of the cannabis plant, a non-psychoactive constituent is cannabidiol (CBD). CBD has been implicated as a potential treatment of a number of disorders including schizophrenia and epilepsy and has been included with THC in a 1:1 combination for the treatment of conditions such as neuropathic pain. This study...
Although alcohol and nicotine administration studies have demonstrated that manipulating subjects' expectancies regarding drug content affects drug response, research with marijuana has not adequately studied drug expectancy effects. The present pilot study was the first to evaluate the credibility and effect of expectancy manipulation on subjective measures and smoking patterns using a...
Abnormalities in psychomotor performance are a consistent finding in schizophrenic patients as well as in chronic cannabis users. The high levels of central cannabinoid (CB(1)) receptors in the basal ganglia, the cerebral cortex and the cerebellum indicate their implication in the regulation of motor activity. Based on the close relationship between cannabis use, the endogenous cannabinoid...
Primarily, rats have served as subjects in Delta(9)-tetrahydrocannabinol's (THC) discrimination studies although other species such as monkeys and pigeons have been used. While the introduction of the knockout and transgenic mice has vastly stimulated the study of the discriminative stimulus effects of drugs there is only a single published report of mice trained to discriminate THC. Thus, this...
Central cannabinoid receptors are thought to mediate neural oscillations and are localized to brain regions implicated in auditory P50 sensory gating, including the hippocampus and neocortex. The current study therefore examined if neural oscillations evoked by the paired clicks (S1, S2) are associated with impaired P50 gating reported in cannabis users. Seventeen heavy cannabis users and 16...
Marijuana and hashish are the illicit drugs most frequently used by human adolescents. Given the continued neurodevelopment throughout adolescence, adolescents may be more vulnerable than adults to certain neural consequences of heavy marijuana use. This study aimed to assess whether an experimental model of adolescent chronic exposure to Delta9-tetrahydrocannabinol (THC), may induce lasting...
Cannabis has been reported as a likely risk factor for the development of psychosis, and a gene × environment interaction with the catechol-O-methyltransferase (COMT) gene has been proposed. Moreover, COMT has been separately linked to affective symptoms in psychosis. Despite a high rate of cannabis abuse and affective symptoms in African Americans, no studies exploring a relationship between...
BACKGROUND: We conducted a systematic review to assess the evidence for specific effects of cannabis on brain structure and function. The review focuses on the cognitive changes associated with acute and chronic use of the drug. METHOD: We reviewed literature reporting neuroimaging studies of chronic or acute cannabis use published up until January 2009. The search was conducted using Medline,...