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"Marijuana abuse"
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Decreased dopamine brain reactivity in marijuana abusers is associated with negative emotionality and addiction severity
Moves to legalize marijuana highlight the urgency to investigate effects of chronic marijuana in the human brain. Here, we challenged 48 participants (24 controls and 24 marijuana abusers) with methylphenidate (MP), a drug that elevates extracellular dopamine (DA) as a surrogate for probing the reactivity of the brain to DA stimulation. We compared the subjective, cardiovascular, and brain DA responses (measured with PET and [ ¹¹C]raclopride) to MP between controls and marijuana abusers. Although baseline (placebo) measures of striatal DA D2 receptor availability did not differ between groups, the marijuana abusers showed markedly blunted responses when challenged with MP. Specifically, compared with controls, marijuana abusers had significantly attenuated behavioral (“self-reports” for high, drug effects, anxiety, and restlessness), cardiovascular (pulse rate and diastolic blood pressure), and brain DA [reduced decreases in distribution volumes (DVs) of [ ¹¹C]raclopride, although normal reductions in striatal nondisplaceable binding potential (BP ND)] responses to MP. In ventral striatum (key brain reward region), MP-induced reductions in DVs and BP ND (reflecting DA increases) were inversely correlated with scores of negative emotionality, which were significantly higher for marijuana abusers than controls. In marijuana abusers, DA responses in ventral striatum were also inversely correlated with addiction severity and craving. The attenuated responses to MP, including reduced decreases in striatal DVs, are consistent with decreased brain reactivity to the DA stimulation in marijuana abusers that might contribute to their negative emotionality (increased stress reactivity and irritability) and addictive behaviors.
Journal Article
The dangers of marijuana
Discusses drug abuse by looking at the scope, use, addiction, treatment, and recovery from marijuana.
Book
Study protocol of a pilot randomized controlled trial of transcranial direct current stimulation paired with reappraisal training for treatment of cannabis use disorder
As legalization of cannabis products continues, cannabis use becomes more prevalent, and concerns regarding cannabis use disorder (CUD) rise, improving CUD treatment has become increasingly important. Techniques used to regulate emotions, such as cognitive reappraisal, may help manage cravings for cannabis in individuals with CUD. Transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, may improve regulation of emotions and reduce substance use. This study aims to determine whether the addition of tDCS to training in cognitive reappraisal leads to greater reductions in cravings and cannabis use than cognitive reappraisal without active stimulation.
This longitudinal between-subjects study will recruit 60 participants who will each be randomly assigned to receive either active or sham tDCS. Participants will undergo 5 sessions, each spaced approximately one week apart. In session, they will receive 20 minutes of (active/sham) 1.5mA anodal stimulation over the right dorsolateral prefrontal cortex while receiving training in cognitive reappraisal. Primary outcomes include changes in cannabis use during the study, changes in electroencephalogram brain activity when viewing cannabis cues, and changes in cannabis craving intensity.
The results of this study will inform a full-scale randomized controlled trial designed to assess the effectiveness of this intervention. More broadly, these results will add to the literature on the role of tDCS in enhancing CUD treatment.
ClinicalTrials.gov NCT06369311.
Journal Article
A Proof-of-Concept Randomized Controlled Study of Gabapentin: Effects on Cannabis Use, Withdrawal and Executive Function Deficits in Cannabis-Dependent Adults
There are no FDA-approved pharmacotherapies for cannabis dependence. Cannabis is the most widely used illicit drug in the world, and patients seeking treatment for primary cannabis dependence represent 25% of all substance use admissions. We conducted a phase IIa proof-of-concept pilot study to examine the safety and efficacy of a calcium channel/GABA modulating drug, gabapentin, for the treatment of cannabis dependence. A 12-week, randomized, double-blind, placebo-controlled clinical trial was conducted in 50 unpaid treatment-seeking male and female outpatients, aged 18-65 years, diagnosed with current cannabis dependence. Subjects received either gabapentin (1200 mg/day) or matched placebo. Manual-guided, abstinence-oriented individual counseling was provided weekly to all participants. Cannabis use was measured by weekly urine toxicology and by self-report using the Timeline Followback Interview. Cannabis withdrawal symptoms were assessed using the Marijuana Withdrawal Checklist. Executive function was measured using subtests from the Delis-Kaplan Executive Function System. Relative to placebo, gabapentin significantly reduced cannabis use as measured both by urine toxicology (p=0.001) and by the Timeline Followback Interview (p=0.004), and significantly decreased withdrawal symptoms as measured by the Marijuana Withdrawal Checklist (p<0.001). Gabapentin was also associated with significantly greater improvement in overall performance on tests of executive function (p=0.029). This POC pilot study provides preliminary support for the safety and efficacy of gabapentin for treatment of cannabis dependence that merits further study, and provides an alternative conceptual framework for treatment of addiction aimed at restoring homeostasis in brain stress systems that are dysregulated in drug dependence and withdrawal.
Journal Article
Trauma and cannabis cue–induced reward circuit functional connectivity in cannabis users with trauma histories
A history of trauma increases risk for excessive and problematic cannabis use, and this relationship may involve conditioned cannabis craving to trauma cues arising through classical and operant conditioning. Alterations in functional connectivity (FC) after trauma reminders within or between brain regions associated with reward processing may potentiate this link; however, the underlying neural mechanisms remain unstudied.
We recruited cannabis users with trauma histories from February 2021 to August 2022. Participants completed a semi-structured interview about a personally relevant traumatic experience, a typical cannabis use situation unrelated to trauma or stress, and an emotionally neutral situation, with responses informing development of 3-minute audiovisual cues. Using a randomized cross-over design, we presented personalized audio recordings and images of the neutral, cannabis-related, and trauma-related situations to participants in counterbalanced order using a cue reactivity paradigm adapted for the magnetic resonance imaging (MRI) environment. Participants self-reported on subjective cannabis craving and positive and negative affect after each cue presentation. We measured FC between striatal, cortical, and limbic regions via functional MRI during each cue.
We included 27 cannabis users with trauma histories (74.1% female, average age 32.2 years, standard deviation 10.5 years). Trauma cues increased cannabis craving and negative affect and decreased positive affect relative to other cues. Cannabis cues increased craving relative to neutral and baseline cues. Trauma cues increased FC within the striatum and between striatal–cortical regions relative to neutral cues and increased striatocortical FC relative to cannabis cues. Cannabis cues increased cortical and corticolimbic FC relative to trauma cues and increased striatocortical FC relative to neutral cues.
The sample was small in size and not formed exclusively of participants with diagnoses of posttraumatic stress disorder or cannabis use disorder.
Findings suggested potential neural mechanisms underlying the link between trauma and cannabis use. Trauma- and cannabis-related cues may potentiate cannabis craving through altered reward circuit FC.
Journal Article
Cannabis users: Screen systematically, treat individually. A descriptive study of participants in a randomized trial in primary care
The aim of the present study was to describe the profiles of a sample of young cannabis users not seeking care, for use in general practice in France.
In this cross-sectional study, baseline data were used from a previous clinical randomized trial, in which a brief intervention was tested. The participants were 262 cannabis users aged 15 to 25 years who smoked at least one joint per month. Assessment was undertaken both by the GP and via an anonymous self-reporting questionnaire. All statistical analyses were performed using Stata software and R. We used multiple correspondence analysis to determine the profiles of users.
Among the 262 patients, 46.2% were daily users (more than 30 joints per month), 25.6% were regular users (from 10 to 29 joints per month), and 28.2% were recent users (fewer than 10 joints per month). The higher the frequency of use, the greater the incidence of unaccompanied use, daily use and week use (p from <0.001 to 0.01). The motivations of daily users were mostly self-treatment and habit (p <0.05). The cannabis abuse screening trial score revealed risky use for 87.5% of daily users and 34.4% for recent users. Factorial analysis identified 5 profiles according to age, risk, and motive for use. The reasons for consultation were equally distributed among users regardless of their level of use or their profile (p > 0.05).
The results provide support for the practice of asking young patients systematically about their cannabis use, allowing GPs to identify users who require medical care. GPs should consider the differences between participants according to their profile in order to determine the appropriate type of care.
Clinicaltrials.gov NCT01433692.
Journal Article
Depressive symptoms and cannabis use in a placebo-controlled trial of N-Acetylcysteine for adult cannabis use disorder
RationaleDepression is common among individuals with cannabis use disorder (CUD), particularly individuals who present to CUD treatment. Treatments that consider this comorbidity are essential.ObjectivesThe goal of this secondary analysis was to examine whether N-acetylcysteine (NAC) reduced depressive symptoms among adults (age 18–50) with CUD (N = 302) and whether the effect of NAC on cannabis cessation varied as a result of baseline levels of depression. Bidirectional associations between cannabis use amount and depression were also examined.MethodsData for this secondary analysis were from a National Drug Abuse Treatment Clinical Trials Network (NIDA CTN) multi-site clinical trial for CUD. Adults with CUD (N = 302) were randomized to receive 2400 mg of NAC daily or matched placebo for 12 weeks. All participants received abstinence-based contingency management. Cannabis quantity was measured by self-report, and weekly urinary cannabinoid levels (11-nor-9-carboxy-Δ9-tetrahydrocannabinol) confirmed abstinence. Depressive symptoms were measured by the Hospital Anxiety and Depression Scale.ResultsDepressive symptoms did not differ between the NAC and placebo groups during treatment. There was no significant interaction between treatment and baseline depression predicting cannabis abstinence during treatment. Higher baseline depression was associated with decreased abstinence throughout treatment and a significant gender interaction suggested that this may be particularly true for females. Cross-lagged panel models suggested that depressive symptoms preceded increased cannabis use amounts (in grams) during the subsequent month. The reverse pathway was not significant (i.e., greater cannabis use preceding depressive symptoms).ConclusionsResults from this study suggest that depression may be a risk factor for poor CUD treatment outcome and therefore should be addressed in the context of treatment. However, results do not support the use of NAC to concurrently treat co-occurring depressive symptoms and CUD in adults.Trial RegistrationClinicaltrials.gov: NCT01675661
Journal Article
Cannabis and cocaine decrease cognitive impulse control and functional corticostriatal connectivity in drug users with low activity DBH genotypes
The dopamine β-hydroxylase (DβH) enzyme transforms dopamine into noradrenaline. We hypothesized that individuals with low activity DBH genotypes (rs1611115 CT/TT) are more sensitive to the influence of cannabis and cocaine on cognitive impulse control and functional connectivity in the limbic ‘reward’ circuit because they experience a drug induced hyperdopaminergic state compared to individuals with high activity DBH genotypes (rs1611115 CC). Regular drug users (
N
= 122) received acute doses of cannabis (450 μg/kg THC), cocaine HCl 300 mg and placebo. Cognitive impulse control was assessed by means of the Matching Familiar Figures Test (MFFT). Resting state fMRI was measured in a subset of participants to determine functional connectivity between the nucleus accumbens (NAc) and (sub)cortical areas. The influence of cannabis and cocaine on impulsivity and functional connectivity significantly interacted with DBH genotype. Both drugs increased cognitive impulsivity in participants with CT/TT genotypes but not in CC participants. Both drugs also reduced functional connectivity between the NAc and the limbic lobe, prefrontal cortex, striatum and thalamus and primarily in individuals with CT/TT genotypes. Correlational analysis indicated a significant negative association between cognitive impulsivity and functional connectivity in subcortical areas of the brain. It is concluded that interference of cannabis and cocaine with cognitive impulse control and functional corticostriatal connectivity depends on DBH genotype. The present data provide a neural substrate and behavioral mechanism by which drug users can progress to drug seeking and may also offer a rationale for targeted pharmacotherapy in chronic drug users with high risk DBH genotypes.
Journal Article
Effect of four-week cannabidiol treatment on cognitive function: secondary outcomes from a randomised clinical trial for the treatment of cannabis use disorder
Rationale
Chronic cannabis use is associated with impaired cognitive function. Evidence indicates cannabidiol (CBD) might be beneficial for treating cannabis use disorder. CBD may also have pro-cognitive effects; however, its effect on cognition in people with cannabis use disorder is currently unclear.
Objectives
We aimed to assess whether a 4-week CBD treatment impacted cognitive function. We hypothesised that CBD treatment would improve cognition from baseline to week 4, compared to placebo.
Methods
Cognition was assessed as a secondary outcome in a phase 2a randomised, double-blind, parallel-group and placebo-controlled clinical trial of 4-week daily 200 mg, 400 mg and 800 mg CBD for the treatment of cannabis use disorder. Participants had moderate or severe DSM-5 cannabis use disorder and intended to quit cannabis use. Our pre-registered primary cognitive outcome was delayed prose recall. Secondary cognitive outcomes were immediate prose recall, stop signal reaction time, trail-making task performance, verbal fluency and digit span.
Results
Seventy participants were randomly assigned to placebo (
n
= 23), 400 mg CBD (
n
= 24) and 800 mg CBD (
n
= 23). A 200 mg group was eliminated from the trial because it was an inefficacious dose at interim analysis (
n
= 12) and was not analysed here. For the primary cognitive outcome, there was no effect of CBD compared to placebo, evidenced by a lack of dose-by-time interaction at 400 mg (0.46, 95%CIs: − 1.41, 2.54) and 800 mg (0.89, 95%CIs: − 0.99, 2.81). There was no effect of CBD compared to placebo on secondary cognitive outcomes, except backwards digit span which increased following 800 mg CBD (0.30, 95%CIs: 0.02, 0.58).
Conclusions
In this clinical trial for cannabis use disorder, CBD did not influence delayed verbal memory. CBD did not have broad cognitive effects but 800 mg daily treatment may improve working memory manipulation.
Clinical trial registration
The trial was registered with ClinicalTrials.gov (NCT02044809) and the EU Clinical Trials Register (2013–000,361-36).
Journal Article