Esketamine combined with a mindfulness-based intervention for individuals with alcohol problems.

Background: Alcohol use disorder (AUD) is a major public health issue, posing harmful consequences for individuals and society. Recent advances in addiction research have highlighted the therapeutic potential of ketamine-assisted therapy for AUD. However, the exact mechanisms underlying its effectiveness remain unknown.

High potency cannabis use, mental health symptoms and cannabis dependence: Triangulating the evidence.

Background: Cannabis potency (concentration of Δ-9-Tetrahydrocannabinol) has been associated with risks of adverse mental health outcomes and addiction but no studies have triangulated evidence from self-report and objective measures of cannabis potency. We hypothesised that users of high potency cannabis would have higher levels of (a) anxiety, (b) depression and (c) psychosis-like symptoms (d) cannabis dependence than users of lower potency cannabis.

Methods: A cross-sectional study of 410 participants donated a sample of cannabis for analysis of THC concentration and reported their cannabis potency preference.

Effects of cannabidiol on anandamide levels in individuals with cannabis use disorder: findings from a randomised clinical trial for the treatment of cannabis use disorder.

Cannabidiol (CBD) has shown promise in treating psychiatric disorders, including cannabis use disorder - a major public health burden with no approved pharmacotherapies. However, the mechanisms through which CBD acts are poorly understood. One potential mechanism of CBD is increasing levels of anandamide, which has been implicated in psychiatric disorders including depression and cannabis use disorder.

Does variation in trait schizotypy and frequency of cannabis use influence the acute subjective, cognitive and psychotomimetic effects of delta-9-tetrahydrocannabinol? A mega-analysis.

Background: While the acute effects of cannabis are relatively benign for most users, some individuals experience significant adverse effects. This study aimed to identify whether variation in schizotypal personality traits and frequency of cannabis use influence the acute effects of delta-9-tetrahydrocannabinol (THC).

Methods: Individual participant data from four double-blind, randomised, placebo-controlled, acute crossover studies involving 128 cannabis users were combined for a mega-analysis.

Acute effects of MDMA on trust, cooperative behaviour and empathy: A double-blind, placebo-controlled experiment.

Background: 3,4-Methylenedioxymethamphetamine (MDMA) is being actively researched as an adjunct to psychotherapy. It may be beneficial to trust, empathy and cooperative behaviour due to its acute prosocial effects.

Aim: To test (a) the acute effects of MDMA on measures of empathy, trust and cooperative behaviour, and (b) subacute changes in mood three days after MDMA administration.

Investigating the Feasibility of Brief Compassion Focused Therapy in Individuals in Treatment for Opioid Use Disorder.

Opioid use disorder (OUD) is reaching epidemic proportions worldwide, and is notoriously difficult to treat. Compassion focused therapy (CFT) has emerged as therapeutic tool for treating individuals exhibiting high levels of self-criticism and low self-esteem, both of which are common in OUD. Until now, however, there had been no research investigating this therapy in patients with OUD.

Greater empathy in MDMA users.

Background: 3,4-Methylenedioxymethamphetamine (MDMA) is widely known for its positive acute effects on social behaviour, such as increasing empathy, whilst also attenuating the negative impact of social exclusion. However there is a scarcity of research that investigates the long-term impact of recreational MDMA use on these fundamental social processes.

Method: Sixty-seven individuals were split into three groups based on their drug-use history: poly-drug MDMA users ( n = 25), poly-drug users who do not use MDMA ( n = 19), alcohol-only users ( n = 23), and were tested in an independent groups design.

A proof-of-concept investigation into ketamine as a pharmacological treatment for alcohol dependence: study protocol for a randomised controlled trial.

Background: Worldwide, alcohol abuse is a burgeoning problem. Abstinence is key to allow recovery of physical and mental health as well as quality of life, but treatment for alcohol dependence is associated with high relapse rates. Preliminary data have suggested that a combined repeated ketamine and psychological therapy programme may be effective in reducing relapse in severe alcohol use disorder.

Acute and chronic effects of cannabinoids on effort-related decision-making and reward learning: an evaluation of the cannabis 'amotivational' hypotheses.

Rationale: Anecdotally, both acute and chronic cannabis use have been associated with apathy, amotivation, and other reward processing deficits. To date, empirical support for these effects is limited, and no previous studies have assessed both acute effects of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), as well as associations with cannabis dependence.

Objectives: The objectives of this study were (1) to examine acute effects of cannabis with CBD (Cann + CBD) and without CBD (Cann-CBD) on effort-related decision-making and (2) to examine associations between cannabis dependence, effort-related decision-making and reward learning.

Keep off the grass? Cannabis, cognition and addiction.

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 been paid to the much more common problem of cannabis addiction.

Associations between cigarette smoking and cannabis dependence: a longitudinal study of young cannabis users in the United Kingdom.

Aims: To determine the degree to which cigarette smoking predicts levels of cannabis dependence above and beyond cannabis use itself, concurrently and in an exploratory four-year follow-up, and to investigate whether cigarette smoking mediates the relationship between cannabis use and cannabis dependence.

Methods: The study was cross sectional with an exploratory follow-up in the participants' own homes or via telephone interviews in the United Kingdom. Participants were 298 cannabis and tobacco users aged between 16 and 23; follow-up consisted of 65 cannabis and tobacco users.

Long-Term Heavy Ketamine Use is Associated with Spatial Memory Impairment and Altered Hippocampal Activation.

Ketamine, a non-competitive N-methyl-d-aspartate receptor antagonist, is rising in popularity as a drug of abuse. Preliminary evidence suggests that chronic, heavy ketamine use may have profound effects on spatial memory but the mechanism of these deficits is as yet unclear. This study aimed to examine the neural mechanism by which heavy ketamine use impairs spatial memory processing.

Acute effects of delta-9-tetrahydrocannabinol, cannabidiol and their combination on facial emotion recognition: a randomised, double-blind, placebo-controlled study in cannabis users.

Acute administration of the primary psychoactive constituent of cannabis, Δ-9-tetrahydrocannabinol (THC), impairs human facial affect recognition, implicating the endocannabinoid system in emotional processing. Another main constituent of cannabis, cannabidiol (CBD), has seemingly opposite functional effects on the brain. This study aimed to determine the effects of THC and CBD, both alone and in combination on emotional facial affect recognition.

Psychiatric morbidity in ketamine users attending counselling and youth outreach services.

Background: No study has examined ketamine users' psychiatric morbidity using structured diagnostic instruments. The aim of this study was thus to determine the psychiatric comorbidity of community-based ketamine users using the Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), Axis I Disorders (SCID).

Methods: A convenience sample of 200 frequent ketamine users was recruited from community organizations in Hong Kong.

Just say 'know': how do cannabinoid concentrations influence users' estimates of cannabis potency and the amount they roll in joints?

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: Participants' own homes.

The link between dopamine function and apathy in cannabis users: an [18F]-DOPA PET imaging study.

Rationale: Cannabis is the most widely used illicit drug in the world, and regular use has been associated with reduced motivation, i.e. apathy.

Abnormalities in white matter microstructure associated with chronic ketamine use.

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 use-on brain structure in humans-remains poorly understood.

Dopaminergic function in cannabis users and its relationship to cannabis-induced psychotic symptoms.

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 schizophrenia is mediated by altered dopaminergic function.

Cannabidiol reduces cigarette consumption in tobacco smokers: preliminary findings.

The role of the endocannabinoid system in nicotine addiction is being increasingly acknowledged. We conducted a pilot, randomised double blind placebo controlled study set out to assess the impact of the ad-hoc use of cannabidiol (CBD) in smokers who wished to stop smoking. 24 smokers were randomised to receive an inhaler of CBD (n=12) or placebo (n=12) for one week, they were instructed to use the inhaler when they felt the urge to smoke.

Harms and benefits associated with psychoactive drugs: findings of an international survey of active drug users.

There have been several recent efforts in the UK and the Netherlands to describe the harms of psychoactive substances based on ratings of either experts or drug users. This study aimed to assess the perceived benefits as well as harms of widely used recreational drugs, both licit and illicit, in an international sample of drug users. The survey was hosted at https://www.

Cannabidiol enhances consolidation of explicit fear extinction in humans.

Rationale: Whilst Cannabidiol (CBD), a non-psychotomimetic cannabinoid, has been shown to enhance extinction learning in rats, its effects on fear memory in humans have not previously been studied.

Objectives: We employed a Pavlovian fear-conditioning paradigm in order to assess the effects of CBD on extinction and consolidation.

Method: Forty-eight participants were conditioned to a coloured box (CS) with electric shocks (UCS) in one context and were extinguished in a second context.

Dopaminergic involvement in effort-based but not impulsive reward processing in smokers.

Background: A reduction in reward responsivity and an increase in temporal discounting of rewards are both evident in smokers during acute abstinence compared to satiation. However, it is not yet known whether these processes can be modulated pharmacologically in smokers, other than with nicotine or tobacco.

Methods: A double-blind placebo controlled crossover design assessed the effects of 0.

Semantic priming and verbal learning in current opiate users, ex-users and non-user controls.

Objective: Despite a growing interest in memory functions of chronic drug users, investigation of semantic and episodic memory in opiate users is limited, and findings of studies have been inconsistent. The present study aimed to assess semantic memory and episodic memory for both drug-related and neutral stimuli in current and ex-users of opiates.

Methods: Using an independent group design, we assessed semantic priming and verbal learning in 16 current opiate users on a methadone maintenance programme, 16 ex-opiate users in rehabilitation programmes and 16 healthy controls.

Associative blocking to reward-predicting cues is attenuated in ketamine users but can be modulated by images associated with drug use.

Rationale: Blocking is an associative learning process that is attenuated in schizophrenia, can be modulated by cue salience and is accompanied by changes in selective attention. Repeated exposure to ketamine can model aspects of schizophrenia, and frequent users selectively attend to images of the drug.

Objectives: This study aimed to establish whether (1) ketamine users show attenuated blocking to reward-predicting cues and (2) drug cues can modulate blocking and cause overshadowing of neutral cues that are equally predictive of reward in these individuals.