Occipital neural dynamics in cannabis and alcohol use: independent effects of addiction.

Alcohol and cannabis use disorder (AUD/CUD) are two of the most common addictive disorders. While studies are beginning to understand the neural changes related to acute and chronic use, few studies have examined the independent effects of AUD and CUD on neural oscillatory activity. We examined 45 adults who reported current use of both cannabis and alcohol. Participants underwent the SCID-V to determine whether they met criteria for AUD and/or CUD. Participants also completed a visual-spatial processing task while undergoing magnetoencephalography (MEG). ANCOVA with a 2 × 2 design was then used to identify the main effects of AUD and CUD on source-level oscillatory activity. Of the 45 adults, 17 met criteria for AUD, and 26 met criteria for CUD. All participants, including comparison groups, reported use of both cannabis and alcohol. Statistical analyses showed a main effect of AUD, such that participants with AUD displayed a blunted occipital alpha (8-16 Hz) response. Post-hoc testing showed this decreased alpha response was related to increased AUD symptoms, above and beyond amount of use. No effects of AUD or CUD were identified in visual theta or gamma activity. In conclusion, AUD was associated with reduced alpha responses and scaled with increasing severity, independent of CUD. These findings indicate that alpha oscillatory activity may play an integral part in networks affected by alcohol addiction.

Cannabis based medicines and cannabis dependence: A critical review of issues and evidence.

Cannabis has been legalised for medical use in an ever-increasing number of countries. A growing body of scientific evidence supports the use of medical cannabis for a range of therapeutic indications. In parallel with these developments, concerns have been expressed by many prescribers that increased use will lead to patients developing cannabis use disorder. Cannabis use disorder has been widely studied in recreational users, and these findings have often been projected onto patients using medical cannabis. However, studies exploring medical cannabis dependence are scarce and the appropriate methodology to measure this construct is uncertain. This article provides a narrative review of the current research to discern if, how and to what extent, concerns about problems of dependence in recreational cannabis users apply to prescribed medical users. We focus on the main issues related to medical cannabis and dependence, including the importance of dose, potency, cannabinoid content, pharmacokinetics and route of administration, frequency of use, as well as set and setting. Medical and recreational cannabis use differs in significant ways, highlighting the challenges of extrapolating findings from the recreational cannabis literature. There are many questions about the potential for medical cannabis use to lead to dependence. It is therefore imperative to address these questions in order to be able to minimise harms of medical cannabis use. We draw out seven recommendations for increasing the safety of medical cannabis prescribing. We hope that the present review contributes to answering some of the key questions surrounding medical cannabis dependence.

Pediatric cannabis poisonings in France: more and more frequent and severe.

CONTEXT: Accidental pediatric cannabis poisonings are an incidental effect of cannabis use. The average THC content of cannabis resin and the number of consumers are rising sharply in the USA and in most European countries. The objective is to study the evolution of prevalence and severity of pediatric exposures to cannabis in France. METHOD: This is a retrospective observational study of cases detected by French poison centers between January 1st 2010 and December 31st 2017 of cannabis exposure by ingestion in children aged ten or younger. The clinical severity was assessed using the Poisoning Severity Score (PSS). The criteria used for assessing the overall severity were as follows: PSS ≥ 2, admission to pediatric intensive care, coma and respiratory depression (univariate and multivariate logistic regression). RESULTS: A total of 965 cases of poisoning were covered. The annual average number of cases was 93 between 2010 and 2014 and 167 between 2015 and 2017. The median age was 15 months (range, 6 months-10 years) and the sex ratio was 1:1. The form of cannabis ingested was mainly resin (75%). During the period covered by the study, 26.1% of children (n = 252) presented with a PSS ≥ 2, 4.5% (n = 43) coma, 4.6% (n = 44) with respiratory depression and 11.7% (n = 113) were admitted into pediatric intensive care (out of 819 hospitalizations). No fatal cases were reported. In comparison to the 2010-2014 period, the length of hospital stays was significantly higher (p < 0.0001) and the comas were significantly deeper (lower score on the Glasgow coma scale, p < 0.005) in 2015-2017. Following adjustments made for the sex, age and weight of the children, the data show that the severity of the poisonings was significantly greater in 2015-2017 in terms of PSS score, the number of comas and monitoring in intensive care (p < 0.001). CONCLUSION: The data indicates a significant increase in the number of cases of pediatric exposure to cannabis and a rise in the seriousness of poisonings between 2010 and 2017.

Modeling the Comorbidity of Cannabis Abuse and Conduct Disorder/Conduct Problems from a Cognitive Neuroscience Perspective.

Objective: A cognitive neuroscience perspective seeks to understand behavior, in this case the comorbidity of cannabis abuse and conduct disorder/conduct problems, in terms of dysfunction in cognitive processes underpinned by neural processes. The goal of this review is to articulate a cognitive neuroscience account of this comorbidity. Methods: Literature on the following issues will be reviewed: (i) the longitudinal relationship between cannabis abuse and conduct disorder/conduct problems (CD/CP); (ii) the extent to which there are genetic and environmental (specifically maltreatment) factors that underpin this relationship; (iii) forms of neurocognitive function that are reported dysfunctional in CD/CP and also, when dysfunctional, appear to be risk factors for future cannabis abuse; and (iv) the extent to which cannabis abuse may further compromise these systems leading to increased future abuse and greater conduct problems. Results: CD/CP typically predate cannabis abuse. There appear to be shared genetic factors that contribute to the relationship between CD/CP and cannabis abuse. Moreover, trauma exposure increases risk for both cannabis abuse and CP/CD. One form of neurocognitive dysfunction, response disinhibition, that likely exacerbates the symptomatology of many individuals with CD also appears to increase the risk for cannabis abuse. The literature with respect to other forms of neurocognitive dysfunction remains inconclusive. Conclusions: Based on the literature, a causal model of the comorbidity of cannabis abuse and CD/CP is developed.

Considering abuse liability and neurocognitive effects of cannabis and cannabis-derived products when assessing analgesic efficacy: a comprehensive review of randomized-controlled studies.

Background: Pain is the most frequent indication for which medical cannabis treatment is sought.Objectives: The clinical potential of cannabis and cannabis-derived products (CDPs) relies on their efficacy to treat an indication and potential adverse effects that impact outcomes, including abuse liability and neurocognitive effects. To ascertain the extent to which these effects impact therapeutic utility, studies investigating cannabis and CDPs for pain were reviewed for analgesic efficacy and assessments of abuse liability and neurocognitive effects.Methods: A comprehensive review of placebo-controlled studies investigating cannabis and CDP analgesia was performed. Methods and findings related to adverse effects, abuse liability, and neurocognitive effects were extracted.Results: Thirty-eight studies were reviewed; 29 assessed cannabis and CDPs for chronic pain, 1 for acute pain, and 8 used experimental pain tests. Most studies ascertained adverse effects through self-report (N = 27). Fewer studies specifically probed abuse liability (N = 7) and cognitive and psychomotor effects (N = 12). Many studies related to chronic and experimental pain (N = 18 and N = 5, respectively) found cannabis and CDPs to reduce pain. Overall, adverse effects were mild to moderate, and dose-related. Studies investigating the impact of cannabis and CDPs on abuse liability and neurocognitive endpoints were mostly limited to inhaled administration and confirmed dose-related effects.Conclusion: Few studies investigating cannabis and CDP analgesia assess abuse liability and cognitive endpoints, adverse effects that impact the long-term clinical utility of these drugs. Future studies should include these measures to optimize research and clinical care related to cannabis-based therapeutics.

Cannabis Use and Consequences.

As an increasing number of states legalize cannabis use for recreational and/or medical purposes, it is increasingly important to understand the neural and cognitive consequences of recreational cannabis use in adolescent consumers. Adolescence is marked by ongoing neuromaturational processes, making this a particularly vulnerable period, particularly regarding exposure to drugs, including cannabis. This review highlights evidence from studies documenting the neural impact of cannabis use in adolescence and explores mediating factors related to cannabis use.

Social and structural factors associated with substance use within the support network of adults living in precarious housing in a socially marginalized neighborhood of Vancouver, Canada.

BACKGROUND: The structure of a social network as well as peer behaviours are thought to affect personal substance use. Where substance use may create health risks, understanding the contribution of social networks to substance use may be valuable for the design and implementation of harm reduction or other interventions. We examined the social support network of people living in precarious housing in a socially marginalized neighborhood of Vancouver, and analysed associations between social network structure, personal substance use, and supporters' substance use. METHODS: An ongoing, longitudinal study recruited 246 participants from four single room occupancy hotels, with 201 providing social network information aligned with a 6-month observation period. Use of tobacco, alcohol, cannabis, cocaine (crack and powder), methamphetamine, and heroin was recorded at monthly visits. Ego- and graph-level measures were calculated; the dispersion and prevalence of substances in the network was described. Logistic mixed effects models were used to estimate the association between ego substance use and peer substance use. Permutation analysis was done to test for randomness of substance use dispersion on the social network. RESULTS: The network topology corresponded to residence (Hotel) with two clusters differing in demographic characteristics (Cluster 1 -Hotel A: 94% of members, Cluster 2 -Hotel B: 95% of members). Dispersion of substance use across the network demonstrated differences according to network topology and specific substance. Methamphetamine use (overall 12%) was almost entirely limited to Cluster 1, and absent from Cluster 2. Different patterns were observed for other substances. Overall, ego substance use did not differ over the six-month period of observation. Ego heroin, cannabis, or crack cocaine use was associated with alter use of the same substances. Ego methamphetamine, powder cocaine, or alcohol use was not associated with alter use, with the exception for methamphetamine in a densely using part of the network. For alters using multiple substances, cannabis use was associated with lower ego heroin use, and lower ego crack cocaine use. Permutation analysis also provided evidence that dispersion of substance use, and the association between ego and alter use was not random for all substances. CONCLUSIONS: In a socially marginalized neighborhood, social network topology was strongly influenced by residence, and in turn was associated with type(s) of substance use. Associations between personal use and supporter's use of a substance differed across substances. These complex associations may merit consideration in the design of interventions to reduce risk and harms associated with substance use in people living in precarious housing.

Adolescent body dissatisfaction and disordered eating: Predictors of later risky health behaviours.

RATIONALE: Body dissatisfaction is prevalent among teenagers, and may influence the uptake of risky health behaviours. OBJECTIVE: The study assessed the influence of body dissatisfaction on smoking, cannabis use, drug use, self-harm, gambling, and drinking and the mediating role of disordered eating in a population-based sample of British adolescents. METHOD: Participants were 2634 females and 1684 males from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. Logistic regression was used to test if body dissatisfaction at 14 years old predicted the onset of risky health behaviours at 21 years old. Mediation analysis tested the mediating role of disordered eating at 16 years old on each risky health behaviour. RESULTS: Among females, body dissatisfaction predicted smoking (OR = 1.40, 95% CI = 1.15, 1.72), cannabis use (OR = 1.20, 95% CI = 1.00, 1.43), drug use (OR = 1.51, 95% CI = 1.20, 1.90), self-harm (OR = 1.44, 95% CI = 1.13, 1.84) and high-risk drinking (OR = 1.41, 95% CI = 1.10, 1.80). Disordered eating symptoms had mediating effects on some behaviours. Among males, body dissatisfaction predicted smoking (OR = 1.44, 95% CI = 1.14, 1.81) and no effect of disordered eating was found on any risky health behaviour. CONCLUSIONS: This is the first prospective study to demonstrate that body dissatisfaction in adolescence predicts the occurrence of several risky health behaviours, and elucidates the mediating role of disordered eating. The findings highlight that body dissatisfaction is a public health concern. Early interventions to promote body satisfaction may reduce the prevalence of later risky health behaviours.

Marijuana use associated with worse verbal learning and delayed recall in a sample of young adults.

BACKGROUND: There is concern about the cognitive consequences of marijuana consumption. AIM: To assess the influence of current and past marijuana use and frequency on verbal learning and memory in a sample of adults aged 21 years old. MATERIAL AND METHODS: Marijuana use was assessed using a clinician administered interview in 654 participants (56% females), who reported frequency of use, age of first use and whether its use led to problems in their lives. The CogState International Shopping List was administered to assess learning and memory. RESULTS: Seventy percent reported ever using marijuana, 46% consuming during the past year and 27% during the past 30 days. The latter scored significantly lower on delayed recall. Current and frequent use were significantly associated with lower accuracy in verbal learning and memory. CONCLUSIONS: In this cohort of adults aged 21 years old, marijuana use was prevalent and related to worse verbal memory.

Religious Affiliation, Informal Participation, and Network Support Associated With Substance Use: Differences Across Age Groups.

Background. Associations between religious involvement and substance use are well established. However, limited research examines the effects of religious affiliation, informal participation, and network support on substance use among two distinct age cohorts. Objectives. This study aims to examine whether religious affiliation, informal participation, and network support are associated with alcohol, tobacco, and marijuana use among young and late middle-age adults. Method. The UC Berkeley Social Networks Study (Wave 1, 2015) offers novel cohort data on young (21-30 years old, n = 483) and late middle-age (50-70 years old, n = 673) adults. Poisson regression models were used to predict alcohol use, while logistic regression models were used to predict odds of smoking and marijuana use. Results. Among young adults, membership in a religious organization was associated with less alcohol, tobacco, and marijuana use. Conversely, participating in informal organizations was associated with more alcohol and marijuana use. Desiring more people to talk to and get together with were associated with more smoking and drinking, respectively. However, wishing more people to ask for help was associated with less substance use altogether. In a similar pattern, among older adults, religious involvement was associated with less alcohol and marijuana use. Desiring more people to ask for help was also related to less marijuana use. Conclusion. Younger adult participation in informal groups serves to encourage social substance use. In contrast, older people are more involved in religious groups, which support social behaviors that do not include substance use.

Marijuana use associated with worse verbal learning and delayed recall in a sample of young adults / El consumo de marihuana se asocia a una menor capacidad de aprendizaje verbal y memoria tardía en adultos jóvenes

ABSTRACT Background: There is concern about the cognitive consequences of marijuana consumption. Aim: To assess the influence of current and past marijuana use and frequency on verbal learning and memory in a sample of adults aged 21 years old. Material and Methods: Marijuana use was assessed using a clinician administered interview in 654 participants (56% females), who reported frequency of use, age of first use and whether its use led to problems in their lives. The CogState International Shopping List was administered to assess learning and memory. Results: Seventy percent reported ever using marijuana, 46% consuming during the past year and 27% during the past 30 days. The latter scored significantly lower on delayed recall. Current and frequent use were significantly associated with lower accuracy in verbal learning and memory. Conclusions: In this cohort of adults aged 21 years old, marijuana use was prevalent and related to worse verbal memory.

Antecedentes: Existe preocupación acerca de los efectos cognitivos del consumo de marihuana. Objetivo: Estudiar el efecto de consumo de marihuana presente o pasado en la capacidad de aprendizaje verbal y memoria en una muestra de adultos de 21 años. Material y Métodos: El consumo de marihuana fue evaluado mediante una entrevista médica en 654 adultos de 21 años (56% mujeres), quienes informaron acerca de la frecuencia de consumo, edad de comienzo y si el consumo les ha causado problemas en sus vidas. Se les administró el Cogstate International Shopping List para evaluar aprendizaje y memoria. Resultados: El 70% informó haber consumido marihuana alguna vez, 46% la usó durante el último año y el 27% en los últimos 30 días. Estos últimos tuvieron un menor puntaje en memoria tardía. El consumo actual y frecuente se asoció a una menor precisión en la capacidad de aprendizaje verbal y memoria. Conclusiones: En esta cohorte de adultos de 21 años, el consumo de marihuana fue prevalente y relacionado a una menor memoria verbal.

Acute cannabis toxicity.

Objective: We describe the clinical effects of, and products associated with, acute exposures to cannabis during the early legalization period of recreational cannabis in Oregon and Alaska. Methods: This was an observational study of Oregon/Alaska Poison Center data between 4 December 2015 and 15 April 2017. A standardized data collection instrument was created for this study that captured information about cannabis product description, route of exposure, intentional vs unintentional exposure, product dose, product manufacture source, product ownership source, initial vital signs, clinical signs and symptoms, and subject disposition. Subjects were included if the Poison Center received a call about an acute exposure to cannabis from the subject, subject's family member or friend, or healthcare worker participating in the subject's care. Subjects were excluded if there was no evident exposure, the exposure was chronic, there were co-ingestants, or the subject was non-human (e.g. pet). Results: Two hundred fifty three individuals were acutely exposed to cannabis (median age 20 years; range 8 months - 96 years; 54.2% males): 71 (28.1%) children (<12 years), 42 (16.6%) adolescents (12-17 years), and 140 (55.3%) adults (≥18 years). Children were most likely to unintentionally (98.6%) ingest (97.2%) homemade (35.2%) edibles (64.8%) belonging to a family member (73.2%) and experience sedation (52.1%). Adults were most likely to intentionally (88.6%) ingest (66.4%) retail (40.0%) edibles (48.6%) and experience neuroexcitation (47.1%). Adolescents' exposures had similarities to both adult and children; they were most likely to intentionally (81.0%) ingest (50.0%) homemade (23.8%) edibles (45.2%) belonging to a friend (47.3%) and to experience either neuroexcitation (42.9%) or sedation (40.5%). Among all ages, tachycardia and neuroexcitation were more likely following inhalation exposures compared to ingestions. Eight subjects were admitted to an intensive care unit, including three patients who were intubated; one subject died. Edibles were the most common products to cause symptoms in all age groups, while concentrated products were more likely to lead to intubation, especially when ingested. Children in particular had a higher likelihood of intensive care unit admission and intubation following exposure to concentrated products. Conclusions: Neurotoxicity is common after acute cannabis exposures. Children experienced unintentional exposures, particularly within the home and occasionally with major adverse outcomes. Concentrated products such as resins and liquid concentrates were associated with greater toxicity than other cannabis products. These findings may help guide other states during the early retail cannabis legalization period.

[Addictions]. / Addictions.

INTRODUCTION: The addictive disorder is a multifactorial pathology variable in its manifestations, environmental, developmental, inheritable, neurobiological, and behavioral. METHODS: Synthesis of recent data from the literature. RESULTS/DISCUSSION: Addiction is a pathology affecting decision-making, the emotional balance, the voluntary control of behaviour, not only in cases of psychoactive products use but also in behavioural dependencies. The social environment, developmental stages, and genetic factors are closely related to the vulnerability to addiction. In this article, after reviewing risk factors and neurobiology data, we will use cannabis, synthetic cannabinoids and cocaine as an example of substance use disorder.

Medical Cannabis Users' Comparisons between Medical Cannabis and Mainstream Medicine.

An evidence-based approach is needed to shape policies and practices regarding medical cannabis, thereby reducing harm and maximizing benefits to individuals and society. This project assesses attitudes towards and utilization of medical cannabis and the mainstream healthcare system among medical cannabis users. The research team administered brief hard copy surveys to 450 adults attending an annual public event advocating for cannabis law reform. Among usable responses (N = 392), the majority (78%) reported using cannabis to help treat a medical or health condition. Medical cannabis users reported a greater degree of use of medical cannabis and a greater degree of trust in medical cannabis compared to mainstream healthcare. In comparison to pharmaceutical drugs, medical cannabis users rated cannabis better on effectiveness, side effects, safety, addictiveness, availability, and cost. Due to the medical use of cannabis, 42% stopped taking a pharmaceutical drug and 38% used less of a pharmaceutical drug. A substantial proportion (30%) reported that their mainstream healthcare provider did not know that they used medical cannabis. Other issues identified included lack of access to mainstream healthcare, self-initiated treatment of health issues, little knowledge of psychoactive content, and heavy cannabis use.

Social Factors and Animal Models of Cannabis Use.

Cannabis, or the dried leaves, stems, and seeds of the hemp plant Cannabis sativa, is the most widely used illicit drug in America. Typically smoked, vaporized or ingested orally, cannabis is used primarily for recreational purposes, though a few synthetic cannabinoids have been approved for medicinal treatments. Psychoactive cannabinoids, or the pharmacologically active compounds within cannabis, are responsible for producing the infamous "high" sensation, characterized by feelings of euphoria and relaxation, though can also provoke hallucinations, paranoia and anxiety. Cannabinoids act on G-protein coupled receptors in the brain, primarilyCB1 receptors, that typically decrease neural activity and modulate transmitter release. Compared to other drugs of abuse, cannabis use has minimal health risks and almost no potential for fatal overdose, though the trademark method of administration (smoking) has detrimental consequences. Chronic heavy use can also lead to changes in memory, cognitive deficits, psychosis and dependence. Up to 9% of users can develop a cannabis dependence, characterized by a characteristic withdrawal syndrome. The growing prevalence of cannabis use has spurred the development of animals models to research the neurobehavioral basis of cannabis use. Traditional animal models of drug abuse (i.e., conditioned place preference (CPP) and self-administration) have historically struggled to establish rewarding or reinforcing effects of individual cannabinoid molecules. Decades of research have been needed to reveal the appropriate dosage and conditions to promote reward and reinforcement in animal models. While the field has made great strides in elucidating the mechanisms involved in behavioral pharmacology cannabinoids, the social aspects of cannabis use remains underrepresented in animal models. Social interactions are vital to the initiation and continuation of cannabis use in humans, and this component has yet to be accurately captured in current animal models.

Novel behavioral assays of spontaneous and precipitated THC withdrawal in mice.

BACKGROUND: A subset of cannabis users develop some degree of Cannabis Use Disorder (CUD). Although behavioral therapy has some success in treating CUD, many users relapse, often citing altered sleep, mood, and irritability. Preclinical animal tests of cannabinoid withdrawal focus primarily on somatic-related behaviors precipitated by a cannabinoid receptor antagonist. The goal of the present study was to develop novel cannabinoid withdrawal assays that are either antagonist-precipitated or spontaneously induced by abstinence. METHODS: C57BL/6 J mice were repeatedly administered the phytocannabinoid Δ9-tetrahydrocannabinol (THC; 1, 10 or 50 mg/kg, s.c.), the synthetic cannabinoid receptor agonist JWH-018 (1 mg/kg, s.c.), or vehicle (1:1:18 parts ethanol:Kolliphor EL:saline, s.c.) for 6 days. Withdrawal was precipitated with the cannabinoid receptor inverse agonist rimonabant (3 mg/kg, i.p.) or elicited via abstinence (i.e., spontaneous withdrawal), and putative stress-related behavior was scored. Classic somatic signs of cannabinoid withdrawal were also quantified. RESULTS: Precipitated THC withdrawal significantly increased plasma corticosterone. Precipitated withdrawal from either THC or JWH-018 suppressed marble burying, increased struggling in the tail suspension test, and elicited somatic withdrawal behaviors. The monoacylglycerol lipase inhibitor JZL184 attenuated somatic precipitated withdrawal but had no effect on marble burying or struggling. Spontaneous THC or JWH-018 withdrawal-induced paw tremors, head twitches, and struggled in the tail suspension test after 24-48 h abstinence. JZL184 or THC attenuated these spontaneous withdrawal-induced behaviors. CONCLUSION: Outcomes from tail suspension and marble burying tests reveal that THC withdrawal is multifaceted, eliciting and suppressing behaviors in these tests, in addition to inducing well-documented somatic signs of withdrawal.

[A Lot of Hot Steam: the Cannabinoid Hyperemesis Syndrome]. / Viel heißer Dampf: das Cannabis-Hyperemesis-Syndrom.

HISTORY: The 43-year-old patient was admitted because of vomiting and abdominal pain. He had a history of depression and multiple discus prolapses. He reported the consumption of three beers per day. FINDINGS: The patient presented diffuse abdominal pain. The serume-kreatine was elevated (205 µmol/l), there was a leucocytosis (18,4^3/µl) and a mild elvation of y-GT (2,3µkat/l). Stool culture was negative. An abdominal ultrasound and a gastroscopy did not show groundbreaking findings. THERAPY AND COURSE: The acute kidney injury was treated by administration of intravenous fluid. The vomiting persisted despite of administration of Metoclopramid and Dimenhydrinat. Just Lorazepam and hot showers brought relief of symptoms. A decided drug history revealed a marijuana abusus. After ceasing marijuana consumption and administration of Haloperidol the vomiting stopped. CONCLUSIONS: The cannabinoid hyperemesis syndrome is characterized by vomiting, diffuse abdominal pain and taking hot showers. With typical combination of symptoms a drug history should be taken. The knowledge of this syndrome can help to avoid overdiagnostic.

Subjective cannabis effects as part of a developing disorder in adolescents and emerging adults.

In light of expanding legalization of cannabis and swelling debate about the potential risks, particularly for younger users, understanding acute cannabis effects among adolescents and emerging adults is more important than ever. Contemporary models of addiction development identify subjective drug responses as central to the developmental unfolding of drug use disorders. Despite this, surprisingly little is known about cannabis's acute subjective effects in human youths. This research utilized ecological momentary assessment (EMA) in the natural environment to identify the typical situational context of cannabis use among 85 frequent cannabis users, ages 15-24 years (M = 19.8, SD = 2.0; 48.2% female). Study aims were to (a) characterize momentary changes in several subjective states (i.e., stimulation, sedation, tension, craving, and high) when not using, just before cannabis use, and after use, and (b) evaluate whether cannabis responses varied with cannabis use disorder (CUD) severity or across the transition from adolescence to emerging adulthood in a correlational manner. Use of cannabis produced measurable reductions in craving and tension, as well as increases in stimulation, sedation, and "high." Participants with more CUD symptoms reported greater relief of craving and increased stimulatory response and high following use. In contrast, emerging adults reported diminished stimulatory response and high following use, relative to adolescents. Results highlight the utility of EMA for characterizing cannabis response as this behavior unfolds in daily life, during a key developmental timeframe in the pathogenesis of cannabis-use pathology. (PsycINFO Database Record

Overlap of heritable influences between cannabis use disorder, frequency of use and opportunity to use cannabis: trivariate twin modelling and implications for genetic design.

BACKGROUND: The genetic component of Cannabis Use Disorder may overlap with influences acting more generally on early stages of cannabis use. This paper aims to determine the extent to which genetic influences on the development of cannabis abuse/dependence are correlated with those acting on the opportunity to use cannabis and frequency of use. METHODS: A cross-sectional study of 3303 Australian twins, measuring age of onset of cannabis use opportunity, lifetime frequency of cannabis use, and lifetime DSM-IV cannabis abuse/dependence. A trivariate Cholesky decomposition estimated additive genetic (A), shared environment (C) and unique environment (E) contributions to the opportunity to use cannabis, the frequency of cannabis use, cannabis abuse/dependence, and the extent of overlap between genetic and environmental factors associated with each phenotype. RESULTS: Variance components estimates were A = 0.64 [95% confidence interval (CI) 0.58-0.70] and E = 0.36 (95% CI 0.29-0.42) for age of opportunity to use cannabis, A = 0.74 (95% CI 0.66-0.80) and E = 0.26 (95% CI 0.20-0.34) for cannabis use frequency, and A = 0.78 (95% CI 0.65-0.88) and E = 0.22 (95% CI 0.12-0.35) for cannabis abuse/dependence. Opportunity shares 45% of genetic influences with the frequency of use, and only 17% of additive genetic influences are unique to abuse/dependence from those acting on opportunity and frequency. CONCLUSIONS: There are significant genetic contributions to lifetime cannabis abuse/dependence, but a large proportion of this overlaps with influences acting on opportunity and frequency of use. Individuals without drug use opportunity are uninformative, and studies of drug use disorders must incorporate individual exposure to accurately identify aetiology.

The gene-environmental architecture of the development of adolescent substance use.

BACKGROUND: Using a longitudinal twin design and a latent growth curve/autoregressive approach, this study examined the genetic-environmental architecture of substance use across adolescence. METHODS: Self-reports of substance use (i.e. alcohol, marijuana) were collected at ages 13, 14, 15, and 17 years from 476 twin pairs (475 boys, 477 girls) living in the Province of Quebec, Canada. Substance use increased linearly across the adolescent years. RESULTS: ACE modeling revealed that genetic, as well as shared and non-shared environmental factors explained the overall level of substance use and that these same factors also partly accounted for growth in substance use from age 13 to 17. Additional genetic factors predicted the growth in substance use. Finally, autoregressive effects revealed age-specific non-shared environmental influences and, to a lesser degree, age-specific genetic influences, which together accounted for the stability of substance use across adolescence. CONCLUSIONS: The results support and expand the notion that genetic and environmental influences on substance use during adolescence are both developmentally stable and developmentally dynamic.