Cannabis Dependence

This study is testing whether brain activity related to learning can help predict how well teens respond to a treatment program designed to reduce cannabis use. Teens ages 14-17 will complete a brain scan and then take part in 10 weekly virtual sessions where they report cannabis use and complete drug tests at home. Participants can earn prizes for staying cannabis-free.

This clinical trial assesses differences in the delivery of THC to the bloodstream depending on whether nicotine vapes are used before or after THC. While there has been much recent publicity about vaping products and concern about their safety considering their increasing use for THC administration, the THC delivery profile associated with THC liquid vaping products in human subjects is currently unknown. Importantly, how the delivery to the bloodstream of THC vaping liquids compare to delivery from smoked cannabis, which is the most used method of cannabis delivery, will serve as an important benchmark for evaluating the delivery and effects of THC vaping products, and their relative safety.

Cognitive impairment is well established in people with psychosis and is associated with cannabis use. The current study will investigate the neurobiological basis of cognitive change associated with 28-days of cannabis abstinence in people with psychosis and non-psychiatric controls with cannabis use. Participants will be randomized to a cannabis abstinent group or a non-abstinent control group and will undergo magnetic resonance imaging at baseline and following 28-days of abstinence. This study will help characterize the neuropathophysiological processes underlying cognitive dysfunction associated with cannabis use and its recovery which may guide the development of novel interventions for problematic cannabis use.

The HASHTAG Study is investigating whether the medicine semaglutide can help adults with cannabis use disorder (CUD) reduce their cannabis use. Participants will be randomly assigned to receive either semaglutide or a placebo. The first 50 participants will have functional brain scans (fMRI) to investigate how the brain responds to cannabis-related cues. The main outcome after 20 weeks is whether semaglutide reduces cannabis use compared to placebo. Changes in brain activity in response to cannabis cues will be explored as a secondary outcome.

The aim of the present study is to assess the availability of cannabinoid receptors (CB1R) in the human brain. CB1R are present in everyone's brain, regardless of whether or not someone has used cannabis. The investigators will image brain cannabinoid receptors using Positron Emission Tomography (PET) imaging and the radioligand OMAR, in healthy individuals and several conditions including 1) cannabis use disorders, 2) psychotic disorders, 3) prodrome of psychotic illness and 4) individuals with a family history of alcoholism, 5) Post-Traumatic Stress Disorder 6) Opioid Use Disorder using the PET imaging agent or radiotracer, \[11C\]OMAR. This will allow us to characterize the number and distribution of CB1R in these conditions. It is likely that the list of conditions will be expanded after the collection of pilot data and as new data on cannabinoids receptor function and psychiatric disorders becomes available. Those in the cannabis us disorder arm of the study will have a PET scan on at least three occasions: once while smoking as usual, once after 48-hours of abstinence from cannabis, and a final time after 4 weeks of abstinence. Additional scans may be conducted within the 4 weeks and the last scan may be conducted well beyond 4 weeks. Similarly, while most schizophrenia patients may get scanned just once, a subgroup of patients may get scanned more than once. For example to tease out the effects of medications, unmedicated patients may get scanned while unmedicated and again after treatment with antipsychotic medications. Similarly prodromes may get scanned while in the prodromal stage off medications, on medications and after conversion to schizophrenia.

Cannabis Abstinence and Neurocognitive Assessment in Adolescence

In Hong Kong, although the total number of drug abusers is trending down in recent years, the number of cannabis users continues to surge. The misuse of cannabis, if left unattended, predisposes various degrees of dependence and use disorders, which could later on induce psychotic disorders and schizophrenia. Effective strategies combating cannabis dependence and cannabis use disorder (CUD) are therefore warranted. Exercise presents as a low-cost and low-stigma alternative to traditional pharmacotherapy and psychotherapy in the treatment of substance use disorders, which also promotes physical well-being with virtually no side effects. While exercise has some success in treating use disorders of stimulants, alcohol, and tobacco, evidence of its effects on CUD remains scarce. Hence, the present study will be conducted to assess the effectiveness of a 12-week aerobic exercise training regimen on reducing cannabis dependence and the severity of CUD. Participants with cannabis dependence will be randomly assigned to either the exercise or the control group. Participants assigned to the exercise group will partake in a 12-week aerobic exercise training program of vigorous-intensity using indoor bikes, whereas those assigned to the control group will perform sham exercise of very light-intensity on indoor bikes. The 12-week study is divided into three (3) 4-week phases: 1. Intensive Intervention - all participants will exercise twice a week under supervision. 2. Active Intervention - all participants will exercise once a week under supervision. 3. Passive Maintenance - no supervised exercise sessions will be provided. All participants will receive exercise reminders via weekly text messages. Cannabis use-related, cognitive, and physical outcomes will be assessed every 4 weeks, whereas withdrawal symptoms will be assessed and urine quick test administered every week.

This study aims to develop an App-based intervention (CANQUIT) aimed at regular cannabis users. The efficacy of this intervention will be evaluated in the short-term (1-month follow-up) and long-term (3- and 6-months follow-ups) using a sample of 120 participants. Participants will be randomly assigned to the experimental arm (App-assisted CBT-based intervention) or the control (App-assisted self-help guide). The study will also estimate the economic impact of the intervention by considering the benefit-cost ratio (BCR) and net benefit (in €) associated with the total cost of the program. The goal is to provide evidence that can inform policy decisions regarding cannabis use and minimize the negative consequences on the physical and mental health of young adults in Spain. This study aims to offer a cost-effective prevention strategy that minimize the negative consequences on the physical and mental health of young adults in Spain.