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BACKGROUND 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. AIMS To study how the varying levels of cannabidiol and THC have an impact on the(More)
AIMS Ketamine remains an important medicine in both specialist anaesthesia and aspects of pain management. At the same time, its use as a recreational drug has spread in many parts of the world during the past few years. There are now increasing concerns about the harmful physical and psychological consequences of repeated misuse of this drug. The aim of(More)
BACKGROUND Cannabis is the most widely used illicit drug globally, and users are at increased risk of mental illnesses including psychotic disorders such as schizophrenia. Substance dependence and schizophrenia are both associated with dopaminergic dysfunction. It has been proposed, although never directly tested, that the link between cannabis use and(More)
AIMS (1) To determine whether measured concentrations of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in individuals' own cannabis predict their estimates of drug potency and actual titration; and (2) to ascertain if these effects are influenced by frequency of use and cannabis type. DESIGN Cross-sectional, naturalistic. SETTING(More)
In an increasing number of states and countries, cannabis now stands poised to join alcohol and tobacco as a legal drug. Quantifying the relative adverse and beneficial effects of cannabis and its constituent cannabinoids should therefore be prioritized. Whereas newspaper headlines have focused on links between cannabis and psychosis, less attention has(More)
BACKGROUND While heavy cannabis-users seem to show various cognitive impairments, it remains unclear whether they also experience significant deficits in affective functioning. Evidence of such deficits may contribute to our understanding of the interpersonal difficulties in cannabis-users, and the link between cannabis-use and psychological disorders(More)
AIM To assess objectively prospective memory (PM) performance of individuals with alcohol dependence and determine whether the use of an imagery technique at the point of encoding can enhance their performance. DESIGN An independent group design was used to compare individuals with alcohol dependence with social drinkers. SETTING One UK residential(More)
AIMS Use of the stimulant drug mephedrone increased dramatically in 2009, and it is still available in the United Kingdom after being controlled in April 2010. This study aimed to assess mephedrone's acute cognitive and subjective effects. DESIGN A mixed within- and between-subjects design compared 20 mephedrone users, first while intoxicated (T1) and(More)
Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist that has been found to induce schizophrenia-type symptoms in humans and is a potent and fast-acting antidepressant. It is also a relatively widespread drug of abuse, particularly in China and the UK. Acute administration has been well characterized, but the effect of extended periods of ketamine(More)
Semantic processing deficits are present in schizophrenia. However, this research has often been criticized for methodological artifacts and confounds, including long hospitalizations and medication of patient samples. Utilizing high schizotypes (psychosis-prone individuals) can overcome these confounds. Previously, similar deficits have been reported in(More)