Clinical Research Directory

Effect of Cannabis on E-Cigarette Use Behavior

The purpose of this study is to determine the impact of tetrahydrocannabinol (THC) administration on motivational, subjective, and physiological effects of electronic cigarettes. The study's goals are to test demand for e-cigarettes, tobacco craving, affect, heart rate, blood pressure, expired breath carbon monoxide, and cognitive performance. Researchers will compare multiple doses of THC and a placebo in participants who smoke e-cigarettes and either smoke or vape THC in the laboratory.

Cannabis Potency Effects on Brain White Matter in Early Phase Psychosis

Canada reports some of the highest rates of cannabis use in our youth and young adult populations, among all the developed countries. Recent Health Canada surveys report that 27% of 16-19-year-olds and 32% of 20-24-year-olds have used cannabis in the past 30 days, with 16-24-year-olds showing the highest rates of daily or near-daily use. Unfortunately, cannabis use has also been found to be a risk factor for the development of a psychotic disorder in emerging adults, and in those who develop psychosis and continue cannabis use, there is a significant effect on long term outcomes. This includes the severity of symptoms, risks of relapse (being hospitalized) and not reaching a level of functioning that would be expected. Lifetime experience with cannabis is greater than 80% in young adults with early phase psychosis (EPP; the first 5 years of a psychosis illness) with up to 30% of Canadian EPP patients meeting criteria for a diagnosis of cannabis use disorder (CUD) at entry to care. A recent Canadian population-based study found that cannabis use disorder associated to psychosis has risen from 3.7% pre-2018 to 10.3% at present. There has been a significant increase in Δ9-tetrahydrocannabinol (THC) levels in cannabis products available globally over the years, with popular cannabis products available start as high as 18% THC in Canada. However high potency cannabis carries a more significant risk for psychosis development, as well as higher risk for cannabis dependence and other severe mental health issues. A major gap in the research is a specific focus on cannabis potency on brain white matter (WM) in youth and young adults, and if there are any potential treatment strategies that could be used to influence any of these cannabis WM effects. To address this, a medication called metformin, that is already used in psychosis to help with side effects of antipsychotic medications, will be used as it has also shown promise to influence WM changes in other illnesses. This project is thus focused on naturalistic cannabis potency effects on WM in emerging adults in EPP (divided into three groups; those using high potency cannabis, low potency cannabis, and minimal cannabis use) and treating them with metformin for 6 months and assessing effects on neuroimaging, cognitive and clinical variables. The purpose of this pilot feasibility study is to inform the development/refinement of an intervention protocol, and not to test potential effects or mechanisms as the sample size will have insufficient power to perform an in-depth analysis. The results of this work will inform our research strategy development and assess feasibility of our novel methodological approach. Participants will: 1. Visit the clinic at baseline, 3 months (only Timeline Follow-Back Assessment administered), and 6 months post baseline to complete substance use and mental health questionnaires, and cognitive assessments 2. Complete an MRI scan at baseline and 6 months 3. Take Metformin every day for 6 months

Effects of Cannabis Species Labeling and Marketing on Perceptual, Subjective and Objective Use Outcomes (Aim 2 Study)

This study looks at how cannabis product label and marketing claims affect product perceptions, use expectancies, and use intentions among inexperienced and experienced cannabis users. Participants will answer online survey questions on their perceptions of a cannabis product advertisement.

Cannabis Effects on Sleep, Circadian Rhythms, and Light Sensitivity in Young Adults

The goal of this study is to learn how cannabis use and discontinuation affect sleep, circadian rhythms, and sensitivity to light. The main questions it aims to answer are: 1. Does cannabis use and discontinuation impact sleep drive? 2. Does cannabis use and discontinuation impact light sensitivity and circadian phase?

Evaluating the Impact of Psychotherapeutic Advertising Claims on Cannabis Purchasing

In the U.S., legal cannabis is frequently advertised as an effective treatment for mental health problems such as anxiety and depression-particularly online. States that have legalized cannabis have not implemented regulations to address this type of advertising. This project aims to investigate the influence of psychotherapeutic advertising claims (PAC) and mental health warning labels (WL) on online cannabis purchasing behaviors among light-to-moderate cannabis users with symptoms of depression and/or anxiety. The specific aims are to determine whether PAC increases cannabis purchasing intentions and whether a mental health WL can mitigate this effect. A realistic online cannabis shopping experience will be simulated using the digital Platform for Online Evaluation of Marijuana Marketing and Sales (POEMMS). The study will employ a between-subjects experimental design by randomizing 2,000 participants to one of four online stores that vary in PAC and WL content: (1) a control claims (CC)-only store, (2) a PAC store, (3) a WL store, and (4) a PAC + WL store. Participants will browse and select items as if making real purchases. Analyses will examine three primary outcomes to determine the influence of PAC and WL on purchasing behaviors: (1) total milligrams of THC purchased, (2) average potency (%THC) of products, and (3) overall number of products purchased. The long-term objective is to inform evidence-based cannabis policy and regulatory strategies by understanding the impact of cannabis marketing on vulnerable populations. This research is relevant to public health by addressing the potential risks associated with misleading cannabis marketing, which may lead to increased use and exacerbation of mental health symptoms among individuals with depression and anxiety. The project leverages a multidisciplinary team with expertise in addiction, mental health, epidemiology, and digital health technology. The findings have the potential to inform the development of targeted interventions and policies to reduce harms associated with cannabis advertising-ultimately contributing to better health outcomes and more effective regulation.

Cannabis-Tobacco Co-Use Treatment Study

The purpose of the RECLAIM study is to evaluate the effectiveness of varenicline (sometimes known as Chantix) compared to placebo (an inactive substance) for the treatment of cigarettes and cannabis (marijuana). Varenicline is not FDA approved for the combination treatment of cigarette abstinence and cannabis reduction or abstinence. All participants will also receive counseling and access to online treatment modules during a quit attempt for cigarettes and a reduction attempt for cannabis. This study is being conducted by the Medical University of South Carolina. All procedures are conducted remotely and there is no in-person visits are needed. To qualify, participants must be 18 or older, live in South Carolina, use cigarettes and cannabis, and are interested in quitting cigarettes and reducing cannabis.

Perceptions of Proposed Warnings for Cannabis Edibles Packaging

The purpose of this study is to compare a delayed-effects warning to an expanded warning developed in previous experiments on knowledge, harm perceptions, and willingness to try cannabis edibles. Additionally, this study will examine the effects of a corresponding icon on attention to and recall of the warning.

Neuroimaging of Adolescent Cannabis Use Treatment

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.

Feasibility and Acceptability Trial to Reduce Tobacco and Cannabis Use During Pregnancy and Postpartum

Using both tobacco and cannabis during pregnancy is more common in minoritized groups and can make quitting smoking in pregnancy and remaining smoke free postpartum difficult. Investigators will test an intervention to address prenatal depressive symptoms to encourage people to quit tobacco and cannabis during pregnancy and stay quit postpartum.

Feasibility/Acceptability of a Brief Motivational Intervention for Frequent/High-Intensity Cannabis Use

The study aims to develop a novel brief motivational mobile health (mHealth) intervention for frequent and/or high-intensity cannabis use for non-collegiate young adults. A total of 120 young adults (ages 18-29, not enrolled at or attending a 4-year college or university) will be randomized to receive a mHealth intervention with text messages for five weeks or to an online resource/program with psychoeducation information about cannabis. The mHealth intervention will focus on prompting the young adult to reflect on their journey with cannabis and to reflect on their personal goals and how cannabis is reflected in these goals. Additional mini-modules are included related to topics such as motivations for use, perceived norms and tracking cannabis use. Participants will return to the program each week to reflect on the prior week and reflect on goals for the upcoming week. All participants will complete a program satisfaction survey and complete follow-up assessments at 3- and 6-months post-program.

Tobacco-Concurrent Addictions in At-Risk Youth in Ottawa

According to the 2015 Ontario Student Drug Use and Health Survey (OSDUHS), there has been a significant increase in the number of secondary school youth who use poly-substances. Not all youth have the same risk for problematic substance use. Health literature documents a high level of comorbidity between mental health and substance use, which is exacerbated in homeless youth populations. Therefore, the proposed study will focus on understanding poly-substance use among at-risk homeless school youth. As seen in substance use research and the PROMPT (2016) study (Participatory Research in Ottawa: Management and Point-of-Care for Tobacco Dependence, PI: Dr. Smita Pakhale), reduction and quitting of one substance (tobacco smoking) can lead to the reduction and quitting of other poly-substance use. A Community-Based Participatory Action Research (CBPAR) approach can help at-risk youth feel safe and comfortable enough to provide personal information about their poly-substance use and engagement with treatment or harm reduction programs. This project will be a first step in increasing health equity among at-risk homeless youth in Downtown Ottawa. The investigators aim to follow a group of at-risk youth to while providing an appropriately modified PROMPT intervention, including peers support and a licensed mental health and substance use nurse.

Examining the Role of Tolerance on Dose-dependent Effects of Acute THC on Oculomotor and Cognitive Performance

The purpose of this research is to determine the extent to which oculomotor function accurately detects THC-impairment, if cannabis use experience impacts this detection threshold, and to examine how the oculomotor index corresponds to a measure of sustained attention. A double-blind, placebo-controlled, within-subjects crossover design will be used to examine the dose-effects of THC (0, 5mg, 30mg) on oculomotor performance tasks and a sustained attention task in frequent and infrequent cannabis users. Results from the study will advance the investigators' understanding of the effect of THC and cannabis use frequency on oculomotor function and sustained attention, and will directly inform the validity of the investigators' oculomotor platform for identifying acute THC- induced impairment in frequent and infrequent users.

Study of Oral Fluid Testing Approach

The purpose of this study is to identify and evaluate oral fluid testing as a biologic measure of cannabis use days that can be assessed remotely. The researchers will conduct this fully virtual study among a community sample of 200 individuals aged 18-30 years who have used cannabis at least 1 time per week on average in the past 30 days. Participants will complete oral fluid (saliva) tests, urine tests, and Timeline Follow-back interviews (self-report) that indicate their recent cannabis use (delta-9-THC). Participants will present for 3 virtual study visits across \~3-4 weeks and be asked to complete activities in between: Study Visit 1 (Day 0; informed consent, baseline survey, TLFB interview), Study Visit 2 (\~Day 7; TLFB interview, urine testing), 6 days of at-home videorecorded oral fluid testing, Study Visit 3 (\~Day 21; TLFB interview, urine test, oral fluid test, survey, interview).

Psychiatric Symptom Characteristics in Methamphetamine-Induced Psychosis With and Without Lifetime Cannabis Use

This prospective cohort study aims to investigate factors associated with psychiatric symptom severity in participants diagnosed with methamphetamine-induced psychotic disorder (MP) with and without lifetime cannabis use (LCU). Participants hospitalized at Elazığ Mental Health and Diseases Hospital who meet Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) criteria for MP will be included. Participants will be divided into two groups based on the presence or absence of LCU. Psychiatric symptoms and clinical characteristics will be assessed weekly during an eight-week inpatient follow-up period using standardized psychometric instruments. The study aims to determine whether LCU influences the course and severity of psychiatric symptoms in MP and to identify environmental, individual, and familial factors associated with symptom progression.

CARS: Cannabis and Alcohol Reduction Study

The study will test a computerized treatment with subjects ages 13-17 years who are seeking treatment for alcohol and/or cannabis use. Follow-up assessments will be conducted at one- and three-months following treatment.

Effectiveness of Brief Intervention in Primary Care for Diverse Young People (Chat)

Brief motivational interviewing intervention to address alcohol use among diverse teens 12-17.

Cannabis, Linked Emotions, and Adolescent Risk Study

The goal of this study is to disentangle relationships between acute cannabis use and withdrawal on proximal depression and suicide risk and recovery in adolescents ages 12-18 years by incorporating time-varying patterns of substance use, mood, and SI. This project aims to guide the development of scalable, individualized, accessible, and affordable interventions aimed to reduce depression and suicide risk among adolescents.

SV2A in Older Adults

The aim of the study is to examine the effect of cannabis use on brain synaptic density among older adults using \[11C\]UCB-J PET imaging.

Precision Brain Stimulation to Reduce Cannabis Craving in Schizophrenia

The central hypothesis is this: Brain circuits most relevant to cannabis use in schizophrenia are distinct from pathways identified in healthy controls who use cannabis. This study seeks to provide evidence that targeted stimulation of the DMN leads to both altered network activity and a concomitant behavioral change in cue-induced craving and cognitive performance in individuals with schizophrenia and schizoaffective disorder, while targeted stimulation of the L DLPFC leads to these changes in healthy controls who use cannabis. This study will test a model that integrates brain network pathophysiology and cognition to 1) explain the prevalence of cannabis use in schizophrenia and 2) identify a target for engagement in schizophrenia. This study seeks to establish a neuroscientific framework to guide future treatment-oriented studies aimed at reducing craving and improving cognitive performance in individuals with schizophrenia and schizoaffective disorder. This is a study of the effect of 2 rTMS interventions on functional connectivity and craving in individuals with schizophrenia or schizoaffective disorder and healthy controls who use cannabis. Aim 1: Target Engagement: Determine if rTMS manipulates functional connectivity of each target (DMN, L DLPFC) (n=100). Aim 2: Clinical Efficacy: Determine if rTMS affects cue-induced craving and if craving change correlates with change in functional connectivity (n=100). As an exploratory analysis, the factors that explain individual variance in rTMS-induced connectivity change will also be explored.

Impact of Cannabis Use During Third Molar Surgery

This study is for people scheduled to have their wisdom teeth (third molars) removed and are going to receive drug through an IV to put them to sleep. The researchers are studying two groups: one group of people who report using recreational marijuana/THC/cannabis and another group who report not using it. They want to look at how both users and non-users do during the tooth removal.

Behavioral Pharmacology of THC and Beta-Myrcene

This study will evaluate the pharmacokinetics and pharmacodynamics of vaporized b-myrcene and THC administered via inhalation.

A Brief Cannabis Use Psychoeducation Intervention for Eating Disorder Patients

The goal of this clinical trial is to learn if providing eating disorder patients with education about the consequences of cannabis (marijuana) use on mental health, gastrointestinal symptoms, eating disorder symptoms, and eating disorder treatment effectiveness increases their knowledge about the cannabis use consequences, intention to reduce cannabis use, and motivation to seek treatment for their cannabis use. The main questions this study aims to answer are: 1. Does education about consequences of cannabis use increase eating disorder patients' knowledge about the risks of cannabis use? 2. Does education about the consequences of cannabis use increase intention to reduce cannabis use and seek cannabis use treatment among those with eating disorders? 3. Does cannabis use interfere with how successful eating disorder treatment is for eating disorder patients? All participants will receive 20 weeks of eating disorder treatment. In week 1 of treatment, participants will either be assigned to receive education about cannabis use consequences, or be assigned to a control condition where they receive education about consequences of poor sleep. Participants will be asked to complete a number of questionnaires that measure knowledge about cannabis use consequences, intention to reduce use and seek cannabis use treatment, eating disorder symptoms, and cannabis use habits. Researchers will assess how effective providing education about cannabis use consequences is on changing knowledge about cannabis use risks, intention to reduce use, and intention to seek cannabis use treatment. It will also be examined if effectiveness of eating disorder treatment is related to cannabis use habits.

Smart Talk: Cannabis Awareness and Prevention Curriculum Evaluation

The Stanford REACH Lab's SMART TALK: Cannabis Awareness and Prevention Toolkit is a free, online educational resource to be used by educators to increase knowledge and awareness of cannabis and reduce use among youth. The aim of this study is to investigate the extent to which the curriculum changes middle and high school students' intentions to use and actual use of cannabis.

Investigating Cannabis Use Parameters on Anesthesia and Inflammation in Lumbar Spinal Surgeries

Cannabis is the most commonly used illicit drug in the United States with reported rates of use increasing from approximately 50 million in 2020 to 61.8 million in 2023 among individuals aged 12 or older. This rise can be attributed to a combination of growing social acceptance and expanding legalization for recreational and medical use of cannabis. Consequently, this has led to increased commercially available cannabis products with heterogeneous concentrations of cannabinoids (i.e., THC:CBD ratios) and new methods of administration becoming more available (e.g., vaping and gummies). Taken together, this rapidly shifting landscape further contributes to the significant variability in individual use patterns (i.e., frequency, duration, and route of administration) resulting in diverse clinical responses, which poses significant challenges for anesthetic management. Recent systematic reviews and meta-analysis have quantitatively demonstrated that cannabis users require higher dosages during anesthesia induction, experience greater hemodynamic instability, and report higher opioid consumption and pain scores post-operatively. These findings have led to the prevailing notion that cannabis exposure adversely affect anesthetic management. Yet, key cannabis exposure parameters in individual use patterns (i.e., variations in THC:CBD ratios, route of administration, frequency, and duration of use) remain poorly characterized and could confound observed clinical effects in relation to their effects on pain modulation and anesthetic requirements. Current perioperative assessments do not account for these critical variables, creating a gap that limits the development of more accurate and personalized anesthetic protocols. Failure to account for individual cannabis exposure parameters may lead to inappropriate anesthetic dosing - where underdosing could result in intraoperative awareness, pain, or patient movement, while overdosing might cause cardiovascular depression, respiratory failure, or prolonged recovery from anesthesia. Concomitantly, researchers have discovered that cannabis consumption modulates immune function such that early life exposure to cannabis produces a long-lasting and persistent inflammatory state characterized by reduced serum levels of IL-6, TNF-α, and IL-2. In contrast, recent research demonstrates that cannabinoid exposure improves skin healing in patients with cutaneous disorders. However, the effects of altered inflammatory responses, and the diverse actions of various cannabinoids on postoperative wound healing remain largely unexplored. Our long-term goal is to elucidate the mechanistic impact of chronic cannabis use parameters on anesthetic and analgesic requirements, thereby enabling the development of personalized, evidence-based perioperative management strategies. The investigators hypothesize that chronic cannabis exposure leads to impaired endogenous pain and immune modulation, resulting in increased intraoperative anesthetic dosing, heightened hemodynamic variability, and elevated postoperative pain and inflammation.