View clinical trials related to Marijuana Abuse.
Filter by:The purpose of this study is to explore sex differences in cognitive functioning and responses to marijuana-related items, and to determine whether stress impacts these measures. Hypothesis 1: Attentional bias will be greater for marijuana cues in male marijuana-dependent subjects relative to female marijuana-dependent or non-dependent male controls. Hypothesis 2: Marijuana-dependent females will exhibit greater stress-induced changes in attentional bias and cognitive functioning than marijuana-dependent males.
This research is studying behaviors that young people engage in that may place them at risk for contracting a sexually transmitted disease like HIV/AIDS, and what kind of educational program works best to reduce these risky behaviors.
Cannabis is the most used illicit substance in the United States. Previous studies suggest that atypical antipsychotics decrease the frequency and the amount of substance use in subjects with and without psychotic illness. So far, there are no controlled studies assessing the effectiveness of atypical antipsychotics for decreasing cannabis and other substance use in individuals with cannabis use disorders. The investigators postulate that the atypical antipsychotic quetiapine ER is an effective agent for improving substance use outcomes in subjects with cannabis use disorders. In this pilot study, the investigators will test this hypothesis in heavy cannabis users (i.e., individuals who are cannabis dependent and smoke three times or more per week). Because 50% of these heavy cannabis users report histories of psychotic experiences (i.e., attenuated positive symptoms) while smoking and are at risk for recurring psychotic symptoms, the investigators will focus this pilot clinical trial on this subgroup of cannabis users in order to increase the risk/benefit ratio of this study and target a population that may also benefit from the antipsychotic effect of quetiapine ER. Considering the lack of controlled studies assessing the efficacy of atypical antipsychotics in heavy cannabis users, assessing the effectiveness of an atypical antipsychotic medication on substance use and clinical outcomes in this population is critical for improving the prognosis of these individuals. Thus, the aims of this randomized, double-blind, placebo-controlled study are to assess the efficacy of an atypical antipsychotic (quetiapine ER) in 120 subjects with cannabis dependence, a recent history (within a year) of attenuated psychotic symptoms, and using cannabis 3 times or more per week for: (1) decreasing the use of cannabis and other substances; and (2) preventing the recurrence of psychotic experiences. The investigators will also assess the effects of quetiapine ER on craving and mood, and its tolerability. This project will be a 12-week, randomized, double-blind, placebo-controlled study with quetiapine ER and it will include a comprehensive assessment of symptoms, substance use, and side effects. This study will benefit the field by providing unique data on the relative efficacy and tolerability of treatment with atypical antipsychotics in heavy cannabis users with a vulnerability to psychosis. This study will be the basis for future studies assessing the long-term efficacy and tolerability of atypical antipsychotics in individuals with cannabis use disorders.
Cannabis use is a significant public health concern that disproportionately affect youth. Although promising psychosocial interventions are being developed, most youth do not benefit from these interventions alone. Given the clinical demand for effective treatments, the National Institute on Drug Abuse (NIDA) identified the critical need for data on the tolerability and potential efficacy of medications in adolescents. The purpose of this two-year study is to test if and how topiramate, a medication under intense study for treating several drugs of abuse, reduces cannabis use among teenagers. To this end, the investigators will randomize 56 nontreatment-seeking regular cannabis users (15 or 20 years old) to receive topiramate or placebo for 6 weeks. Youth will monitor their cannabis use for the 6-week period using handheld electronic diaries and complete assessments of reactivity to cannabis-related cues.
This study will test a behavioral intervention tailored for adolescents who smoke marijuana and have concerns about their use. The study's purpose is to determine whether this intervention (two-sessions of motivational enhancement intervention followed by 12 months of optional skills training) will be more effective in reducing the use of this drug if augmented by three periodic motivational enhancement treatment check-in sessions as compared to three periodic computer-based check-in sessions. HYPOTHESES: (1) Participants in the motivational enhancement treatment check-ins (MCI) condition will reduce their use of marijuana more than participants in the computer based (Comp) condition and report fewer negative consequences. These differences are expected to be greater at later follow-ups (i.e, 9, 12, and 15 months) after repeated check-ins exert a cumulative effect. (2)Engagement in CBT sessions will be greater for those in the MCI condition and will partially mediate the effect on marijuana related outcome indices. (3) The MCI intervention will lead to increased self-efficacy, and decreased normative perceptions of marijuana use by other teens that will also partially mediate the effect of the intervention.
The main hypothesis is that persons that smoke or smoked tobacco and marihuana have worsen lung function as compared with persons that only smoke or smoked tobacco.
Background: - Little research has been done on how different components of cannabis (marijuana) appear in oral fluid (i.e., saliva) after smoking. Cannabinoids have been well studied in whole blood, plasma, and urine after cannabis use, but less is known about how cannabinoids appear in oral fluid after controlled drug administration and how long these biomarkers last after use. In addition, the issue of stability of cannabinoids and their glucuronide metabolites is a controversial topic that is poorly understood. These data are critical to the interpretation of cannabinoid test results. Objectives: - To collect whole blood, plasma, urine, and oral fluid specimens after smoking cannabis, to characterize the disposition and pharmacokinetics of cannabinoids in multiple biological matrices and to provide scientifically reliable data on the stability of cannabinoids and metabolites. - To test basic brain function and thinking processes after smoking cannabis. Eligibility: - Healthy volunteers between 18 and 45 years of age who use cannabis (an average of at least twice per month in the 3 months before the study.) Design: - Participants may complete the single study session as outpatients, or they may spend the night prior to and/or following drug administration at the residential research unit in Baltimore, MD. Participants must provide a negative urine drug screen if they have not spent the evening prior to testing at the research unit. - Participants will provide whole blood, plasma, oral fluid, and urine samples, and will complete several tests of thinking and brain function at the start of the study. - Participants will smoke one standardized cannabis cigarette. Blood and oral fluid samples will be collected, and participants will repeat the tests of thinking and brain function multiple times after smoking. - Six hours after smoking the cigarette, participants must pass a neuromotor exam (testing balance and coordination) before they can be discharged from the study. Participants may be asked to stay overnight at the clinical center if there are concerns for their safety because of intoxication.
Background: Rimonabant, a CB1 receptor antagonist, blocks effects of cannabinoids and, in dependent animals, elicits cannabinoid withdrawal. No studies have examined rimonabantelicited cannabis withdrawal in humans. Goals: (1) Determine the lowest single dose of oral rimonabant that elicits measurable cannabinoid withdrawal. (2) Characterize cognitive performance, subjective state, physiological condition, and regional brain activation (measured by functional magnetic resonance imaging [fMRI]) during acute and chronic administration of oral delta 9-tetrahydrocannabinol (THC) and during cannabis withdrawal. (3) Characterize the pharmacokinetics of oral THC and metabolites in body fluids and hair and of rimonabant in plasma. Subject Population: Up to 60 completing cannabis users aged 18-45 (up to 24 in Experiment I, 36 in Experiment II) and 18 completing non-drug-using controls (Experiment II). Enrollment target is 82% Caucasian, 14% African American, 4% other; 9% Hispanic; 35% women. Experimental Design and Methods: Experiment I: In this within-subject, randomized, double-blind, dose-escalation study, six participants receive 7 days of THC (40-120 mg/day). On Day 8, five participants receive 20 mg rimonabant; one receives placebo. If withdrawal criteria (greater than or equal to 150% or 2.5-fold increase in selected visual-analog scales) are not met in all five participants receiving rimonabant, separate groups of six are similarly treated with 40, 60 or 80 mg rimonabant, if necessary. The PI and MRP will submit all adverse events and relevant cardiovascular and scientific data to the IRB at the completion of each rimonabant dose panel. When the extramural NIDA DSMB is in place, it will review all data collected to date and develop and implement a monitoring plan, including review on completion of each dose cohort. DSMB recommendations will be reviewed by the Sponsor, Clinical Director and IRB before proceeding to the next dose cohort. In addition, if any subject has an intolerable adverse event (ie, an adverse event leading to study discontinuation) or serious adverse event in response to rimonabant on Day 8, the blind for that subject will be broken, and a report sent to the Sponsor, the extramural NIDA DSMB when in place and the IRB for discussion. Experiment II: In this randomized, placebo-controlled, double-blind study, 36 participants receive 7 days of THC (40-120 mg/day). On Day 8, 18 participants receive rimonabant dose determined in Experiment I to elicit cannabis withdrawal; 18 participants receive placebo rimonabant to evaluate spontaneous cannabis withdrawal. Cognitive, psychological, physiological and hormonal measures are monitored to determine onset, magnitude, and duration of THC intoxication and withdrawal and to correlate with THC and rimonabant pharmacokinetics. Changes in blood oxygen level-dependent (BOLD) signal are determined with five fMRI scans throughout the study. Eighteen non-drug-using controls undergo scanning and cognitive testing at similar intervals. Risks and Benefits: The proposed doses of THC and rimonabant have been well tolerated in other studies. The most common side effects of oral THC are sedation, cognitive impairment, euphoria, poor coordination, tachycardia, and hypotension. Spontaneous withdrawal from cannabis is mild and medically benign. Experience with other drugs suggests that antagonist-elicited cannabis withdrawal may have an earlier onset and greater intensity than spontaneous cannabis withdrawal. There are no clinical benefits to participants. Scientific benefits are greater understanding of cannabis intoxication, tolerance, and withdrawal and of the role of rimonabant in eliciting cannabis withdrawal.
The purpose of the study is to determine why and how marijuana users stop or reduce their marijuana use.
Background: - The therapeutic modalities of cannabis have received more research attention recently with the discovery of its ability to stimulate appetite and to provide pain and nausea relief in patients with AIDS, cancer, and multiple sclerosis, among other diseases. Sativex(Registered Trademark), an experimental drug derived from the marijuana plant, contains tetrahydrocannabinol (THC) and cannabidiol (CBD), both of which affect brain activity. Sativex(Registered Trademark) is being tested to determine how and to what extent it affects brain activity. - Functional magnetic resonance imaging (fMRI) uses magnetic waves to study brain activity. Researchers are interested in using fMRI to study how Sativex(Registered Trademark) affects regional brain activity, including thinking abilities and behavior. Objectives: - To study changes in regional brain activity produced by Sativex(Registered Trademark) compared with THC and placebo. - To determine how Sativex(Registered Trademark) is processed by the body. Eligibility: - Individuals between 18 and 45 years of age who are either current users of cannabis (less than daily) or healthy volunteers who do not use cannabis. Design: - The study will involve one training session and five testing sessions on separate days. - At every session, subjects will receive either THC or placebo capsules and either Sativex(Registered Trademark) or placebo spray. - Participants will complete a training session in a mock fMRI scanner to adapt to the fMRI scanning environment. In the training session, participants will practice the tests that will track thinking ability, attention, working memory, and other cognitive tasks. - Participants will have five fMRI scanning sessions with the tests they have practiced previously, and will provide blood, urine, and saliva samples as required by the researchers. Participants will be discharged approximately 12 hours after they arrive for the study sessions....