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.

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.

Marijuana Legalization: Impact on Physicians and Public Health.

Marijuana is becoming legal in an increasing number of states for both medical and recreational use. Considerable controversy exists regarding the public health impact of these changes. The evidence for the legitimate medical use of marijuana or cannabinoids is limited to a few indications, notably HIV/AIDS cachexia, nausea/vomiting related to chemotherapy, neuropathic pain, and spasticity in multiple sclerosis. Although cannabinoids show therapeutic promise in other areas, robust clinical evidence is still lacking. The relationship between legalization and prevalence is still unknown. Although states where marijuana use is legal have higher rates of use than nonlegal states, these higher rates were generally found even prior to legalization. As states continue to proceed with legalization for both medical and recreational use, certain public health issues have become increasingly relevant, including the effects of acute marijuana intoxication on driving abilities, unintentional ingestion of marijuana products by children, the relationship between marijuana and opioid use, and whether there will be an increase in health problems related to marijuana use, such as dependence/addiction, psychosis, and pulmonary disorders. In light of this rapidly shifting legal landscape, more research is urgently needed to better understand the impact of legalization on public health.

Old and new synthetic cannabinoids: lessons from animal models.

Synthetic cannabinoids have long been studied for their therapeutic potentials. However, during the last decade, new generations of synthetic cannabinoid agonists appeared on the drug market. These new psychoactive substances are currently sold as 'marijuana-like' products as they claim to mimic the effects of the psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC). Yet, their effects are more intense and potent than THC, typically last longer and are often associated to serious psychiatric consequences. Animal models of drug addiction are frequently used in preclinical research to assess the abuse potential of new compounds, evaluate drug positive reinforcing effects and analyze drug-induced behaviors. Some of these protocols have been used recently to study the newly synthesized cannabinoid agonists and have started elucidating their pharmacology and actions in the brain. The aim of this review is to summarize the major findings reported by animal studies that tested synthetic cannabinoids of first, second, and third generation by using self-administration and reinstatement models, drug discrimination and conditioned place preference procedures. Altogether, behavioral studies clearly indicate that synthetic cannabinoids possess abuse liability, are likely to activate the brain reward circuit and induce positive subjective and reinforcing effects.

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.

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.

Direct and indirect effects of false safety behaviors on cannabis use and related problems.

BACKGROUND AND OBJECTIVES: In light of increasing rates of cannabis use and use-related problems, efforts to understand malleable psychological vulnerability factors related to use and related problems remain important as they can inform prevention and treatment efforts. Recent data indicate that false safety behaviors (FSB; ie, behaviors that may be effective in decreasing anxiety in the short-term, but can maintain and even exacerbate anxiety in the long-term) are related to cannabis problem severity. Thus, an important next step is to identify factors implicated in the relation between FSB and cannabis use behavior. The current study tested whether FSB were uniquely related to cannabis use problems and high-risk cannabis use motives. We also tested whether FSB were indirectly related to cannabis outcomes via high-risk motives. METHOD: The sample consisted of 349 current (69.6% female) cannabis-using undergraduates who completed an online survey. RESULTS: FSB was robustly related to cannabis-related problems and cannabis use motives (ie, coping and availability) after controlling for anxiety and cannabis use frequency. FSB was indirectly related to cannabis problems via coping and availability motives and to cannabis use frequency via coping motives. DISCUSSION AND CONCLUSIONS: Results add to a growing literature indicating that FSB are related to cannabis problem severity and extend this work by identifying mechanisms underlying this relationship. SCIENTIFIC SIGNIFICANCE: Data indicate that FSB may be an under recognized, yet clinically important, vulnerability factor related to cannabis use problems. (Am J Addict 2018;27:29-34).

Association between alcohol, cannabis, and other illicit substance abuse and risk of developing schizophrenia: a nationwide population based register study.

BACKGROUND: Several studies have examined whether use of substances can cause schizophrenia. However, due to methodological limitations in the existing literature (e.g. selection bias and lack of adjustment of co-abuse) uncertainties still remain. We aimed to investigate whether substance abuse increases the risk of developing schizophrenia, addressing some of these limitations. METHOD: The longitudinal, nationwide Danish registers were linked to establish a cohort of 3 133 968 individuals (105 178 673 person-years at risk), identifying 204 505 individuals diagnosed with substance abuse and 21 305 diagnosed with schizophrenia. Information regarding substance abuse was extracted from several registers and did not include psychotic symptoms caused by substance abuse in the definition. This resulted in a large, generalizable sample of exposed individuals. The data was analysed using Cox regression analyses, and adjusted for calendar year, gender, urbanicity, co-abuse, other psychiatric diagnosis, parental substance abuse, psychiatric history, immigration and socioeconomic status. RESULTS: A diagnosis of substance abuse increased the overall risk of developing schizophrenia [hazard ratio (HR) 6.04, 95% confidence interval (CI) 5.84-6.26]. Cannabis (HR 5.20, 95% CI 4.86-5.57) and alcohol (HR 3.38, 95% CI 3.24-3.53) presented the strongest associations. Abuse of hallucinogens (HR 1.86, 95% CI 1.43-2.41), sedatives (HR 1.68, 95% CI 1.49-1.90), and other substances (HR 2.85, 95% CI 2.58-3.15) also increased the risk significantly. The risk was found to be significant even 10-15 years subsequent to a diagnosis of substance abuse. CONCLUSION: Our results illustrate robust associations between almost any type of substance abuse and an increased risk of developing schizophrenia later in life.

[Cannabis-induced disorders]. / Cannabisinduzierte Störungen.

Use and misuse of cannabis and marihuana are frequent. About 5% of the adult population are current users but only 1.2% are dependent. The medical use of cannabis is controversial but there is some evidence for improvement of chronic pain and spasticity. The somatic toxicity of cannabis is well proven but limited and psychiatric disorders induced by cannabis are of more relevance, e.g. cognitive disorders, amotivational syndrome, psychoses and delusional disorders as well as physical and psychological dependence. The withdrawal symptoms are usually mild and do not require pharmacological interventions. To date there is no established pharmacotherapy for relapse prevention. Psychosocial interventions include psychoeducation, behavioral therapy and motivational enhancement. The CANDIS protocol is the best established German intervention among abstinence-oriented therapies.

THC:CBD in Daily Practice: Available Data from UK, Germany and Spain.

BACKGROUND: From the time Sativex (THC:CBD) oromucosal spray first became available in European Union countries in 2010 for the management of treatment-resistant multiple sclerosis (MS) spasticity, data from daily practice have been collected through various projects. METHODS: A retrospective registry study and a prospective safety study of THC:CBD oromucosal spray are reported. RESULTS: The most recent analysis of a retrospective registry established in the United Kingdom (UK), Germany and Switzerland, which collected safety data on more than 900 patients, has indicated a positive risk-benefit profile for THC:CBD oromucosal spray during long-term use. Long-term continuation rates were 68% (mean follow-up time 1 year) and the mean dose was 5.4 sprays/day. No new safety concerns were identified, and adverse events of special interest for a cannabis-based medicine were limited. The UK registry has since been closed but remains open in Germany and Switzerland. A prospective safety study undertaken in Spain involved 207 patients from 13 specialized MS centres who had been prescribed THC:CBD oromucosal spray. The findings aligned closely with the UK/German/Swiss registry data in terms of 1-year continuation rates (64.7%), mean daily dose (6.6 sprays/day) and safety profile, including no evidence of addiction, abuse or misuse. CONCLUSIONS: The homogeneity between these observational studies supports the interest in THC:CBD oromucosal spray for management of MS spasticity in daily practice.

The Gateway Hypothesis, Common Liability to Addictions or the Route of Administration Model A Modelling Process Linking the Three Theories.

BACKGROUND: The aim of this study was to describe the transitions between tobacco (T), cannabis (C) and other illicit drugs (OIDs) initiations, to simultaneously explore several substance use theories: gateway theory (GT), common liability model (CLM) and route of administration model (RAM). METHODS: Data from 2 French nationwide surveys conducted in 2005 and 2010 were used (16,421 subjects aged 18-34). Using reported ages at initiations, we reconstituted a retrospective cohort describing all initiation sequences between T, C and OID. Transition probabilities between the substances were computed using a Markov multi-state model that also tested the effect of 2 latent variables (item response theory scores reflecting propensity for early onset and further substance use) on all transitions. RESULTS: T initiation was associated with increased likelihood of subsequent C initiation, but the reverse relationship was also observed. While the most likely initiation sequence among subjects who initiated the 3 groups of substances was the 'gateway' sequence T x2192; C x2192; OID, this pattern was not associated with substance use propensity more than alternative sequences. Early use propensity was associated with the 'gateway' sequence but also with some alternative ones beginning with T, C or OID. CONCLUSION: If the gateway sequence appears as the most likely pattern, in line with GT, the effects of early onset and substance use propensities were also observed for some alternative sequences, which is more in line with CLM. RAM could explain reciprocal interactions observed between T and C. This suggests shared influences of individual (personality traits) and environmental (substance availability, peer influence) characteristics.

[Cannabis--Position Paper of the German Respiratory Society (DGP)]. / Cannabis--Positionspapier der Deutschen Gesellschaft für Pneumologie und Beatmungsmedizin e.V. (DGP).

In this position paper, the adverse health effects of cannabis are reviewed based on the existing scientific literature; in addition possible symptom-relieving effects on some diseases are depicted. In Germany, cannabis is the most widely used illicit drug. Approximately 600,000 adult persons show abusive or addictive cannabis consumption. In 12 to 17 year old adolescents, cannabis use increased from 2011 to 2014 from 2.8 to 6.4%, and the frequency of regular use from 0.2 to 1.5%. Currently, handling of cannabinoids is much debated in politics as well as in general public. Health aspects have to be incorporated into this debate. Besides analysing mental and neurological side effects, this position paper will mainly focus on the influences on the bronchopulmonary and cardiovascular system. There is strong evidence for the induction of chronic bronchitis. Allergic reactions including asthma are known, too. Associations with other diseases like pulmonary emphysema, lung cancer and pneumonia are not sufficiently proven, however cannot be excluded either. In connection with the use of cannabis cardiovascular events such as coronary syndromes, peripheral vascular diseases and cerebral complications have been noted. Often, the evidence is insufficient due to various reasons; most notably, the overlapping effects of tobacco and cannabis use can frequently not be separated adequately. Empirically, early beginning, high-dosed, long-lasting and regular cannabis consumption increase the risk of various psychological and physical impairments and negatively affect age-based development. Concerns therefore relate especially to children and adolescents. There is only little scientific evidence for medical benefits through cannabis as a remedy; systematic research of good quality, in particular prospective, randomised, placebo-controlled double-blinded studies are rare. The medical societies signing this position paper conclude that cannabis consumption is linked to adverse health effects which have to be taken into consideration in the debate about the social attitude towards cannabinoids. The societies agree that many aspects regarding health effects of cannabis are still uncertain and need clarification, preferably through research provided by controlled studies.

Three-Year Course of Cannabis Dependence and Prediction of Persistence.

AIMS: To examine the course and the predictors of the persistence of cannabis dependence. METHODS: Through cannabis outlets and chain referral, a prospective enriched community cohort of 207 young adults (aged 18-30) with DSM-IV cannabis dependence at baseline (T0) was formed and followed-up after 1.5 (T1) and 3 (T2) years. The presence of cannabis dependence, cannabis-related problems, functional impairment and treatment was assessed using the Composite International Diagnostic Interview (CIDI 3.0) and the Sheehan Disability Scale (SDS). Predictors of persistence were lifetime cannabis abuse and dependence symptoms, cannabis use characteristics, distant vulnerability factors (e.g. childhood adversity, family history of psychological/substance use problems, impulsivity, mental disorders), and proximal stress factors (recent life events, social support). RESULTS: Four groups were distinguished: persistent dependent (DDD: 28.0%), stable non-persistent (DNN: 40.6%), late non-persistent (DDN: 17.9%) and recurrent dependent (DND: 13.5%). At T2, persisters (DDD) reported significantly more (heavy) cannabis use and cannabis problems than non-persisters (DNN/DDN/DND). Treatment seeking for cannabis-related problems was rare, even among persisters (15.5%). The number (OR = 1.23 (1.03-1.48)) and type ('role impairment' OR = 2.85 (1.11-7.31), 'use despite problems' OR = 2.34 (1.15-4.76)) of lifetime cannabis abuse/dependence symptoms were the only independent predictors of persistence with a total explained variance of 8.8%. CONCLUSIONS: Persistence of cannabis dependence in the community is low, difficult to predict, and associated with a negative outcome. The substantial proportion of stable non-persisters suggests that screening and monitoring or low-threshold brief interventions may suffice for many non-treatment-seeking cannabis-dependent people. However, those with many lifetime abuse/dependence symptoms may benefit from more intensive interventions.

Reasons for recent marijuana use in relation to use of other illicit drugs among high school seniors in the United States.

OBJECTIVES: Studies show that illicit cannabis (marijuana) use is related to use of other illicit drugs and that reasons for use are related to frequency of marijuana use. However, research is needed to examine whether specific reasons for marijuana use are associated with use of other illicit drugs. METHODS: Data from recent marijuana-using high school seniors were examined from 12 cohorts of Monitoring the Future (Weighted n = 6481) to examine whether reasons for recent marijuana use are associated with use of eight other illicit drugs. RESULTS: Using "to experiment" decreased odds of reporting use of each drug and using to decrease effects of other drugs increased odds of reporting use of each drug. In multivariable models, using marijuana "to experiment" decreased the odds for reporting use of hallucinogens other than LSD and narcotics other than heroin. Using marijuana for "insight" increased the odds for use of hallucinogens other than LSD, and use due to "boredom" increased the odds for reporting use of powder cocaine and hallucinogens other than LSD. Using marijuana to increase effects of other drugs increased odds of reporting use of each of the eight drugs, and using it to decrease other drug effects increased odds of reporting use of crack, hallucinogens other than LSD, and amphetamine/stimulants. CONCLUSIONS: This study helped identify illicit marijuana users who are more likely to report use of other illicit drugs. Prevention efforts need to focus on students who report certain reasons for marijuana use as they may be at risk for use of other illicit drugs.

Exposure to violence, substance use, and neighborhood context.

Adolescent exposure to violence and substance use are both public health problems, but how neighborhood context contributes to these outcomes is unclear. This study uses prospective data from 1416 adolescents to examine the direct and interacting influences of victimization and neighborhood factors on adolescent substance use. Based on hierarchical Bernoulli regression models that controlled for prior substance use and multiple individual-level factors, exposure to violence significantly increased the likelihood of marijuana use but not alcohol use or binge drinking. There was little evidence that community norms regarding adolescent substance use influenced rates of substance use or moderated the impact of victimization. Community disadvantage did not directly impact substance use, but the relationship between victimization and marijuana use was stronger for those in neighborhoods with greater disadvantage. The results suggest that victimization is particularly likely to affect adolescents' marijuana use, and that this relationship may be contingent upon neighborhood economic conditions.

Marijuana for Glaucoma: A Recipe for Disaster or Treatment?

Marijuana has been shown to lower intraocular pressure (IOP) but with limited duration of action and numerous adverse effects. Use of marijuana to lower IOP as a means of glaucoma treatment would require frequent use throughout the day, leading to significant adverse effects, possible progression toward Cannabis Use Disorder (CUD), and/or withdrawal symptoms. The treatment of glaucoma based on the cannabis plant or drugs based on the cannabinoid molecule should be considered carefully before being prescribed. Considerations should include the adverse physical and psychological adverse effects, including substance abuse. Currently, the deleterious effects of marijuana outweigh the benefits of its IOP-lowering capacity in most glaucoma patients. Under extremely rare circumstances, a few categories of glaucoma patients may be potential candidates for treatment with medical marijuana. Further studies on alternate routes and more focused means of cannabinoid molecule delivery to the eye for glaucoma treatment are needed.

Trauma exposure, posttraumatic stress disorder and risk for alcohol, nicotine, and marijuana dependence in Israel.

BACKGROUND: Substance dependence is more common among trauma-exposed individuals; however, most studies suggest that Posttraumatic Stress Disorder (PTSD) accounts for the link between trauma exposure (TE) and substance dependence. OBJECTIVES: This study examined associations between TE and substance dependence (alcohol, nicotine, and marijuana), and whether PTSD accounted for this association. METHOD: 1317 Jewish Israeli household residents completed in-person structured interviews assessing TE, PTSD, and substance (alcohol, nicotine, marijuana) dependence between 2007 and 2009. Regression analyses examined associations among TE, PTSD, and substance dependence. RESULTS: In the full sample, mean number of traumatic events was 2.7 (sd=2.2), with 83.7% experiencing at least one event. In the full sample, mean number of PTSD symptoms was 2.5 (sd=3.4), with 13.5% meeting PTSD diagnostic criteria. Prevalence of alcohol dependence was 13.4%; nicotine dependence 52.8%; and marijuana dependence 12.1%. Number of traumatic events was associated with increased odds of alcohol (OR=1.3; 95% CI=1.2-1.4) and nicotine (OR=1.2; 95% CI=1.1-1.3) dependence. Similarly, any traumatic event exposure was associated with increased odds of alcohol (OR=3.1; 95% CI=1.6-6.0) and nicotine (OR=1.9; 95% CI=1.2-2.9) dependence. PTSD symptoms were associated with increased odds of alcohol (OR=1.2; 95% CI=1.1-1.3), nicotine (OR=1.1; 95% CI=1.1-1.2), and marijuana (OR=1.1; 95% CI=1.04-1.2) dependence; similarly, a PTSD diagnosis was associated with increased odds of alcohol (OR=3.4; 95% CI=2.1-5.5), nicotine (OR=2.2; 95% CI=1.4-3.4), and marijuana (OR=2.6; 95% CI=1.2-5.9) dependence. PTSD symptoms accounted for a sizeable proportion of the TE effect on alcohol (46%) and nicotine dependence (31%). CONCLUSION: Individuals with more traumatic events had heightened risk for alcohol and nicotine dependence, and PTSD symptoms partially accounted for this risk. However, marijuana dependence was only significantly related to PTSD symptoms. Clinicians and researchers should separately assess different types of dependence among trauma-exposed individuals both with and without PTSD symptoms.

The internalizing pathway to adolescent substance use disorders: mediation by ruminative reflection and ruminative brooding.

Two subtypes of rumination were examined in relationship to substance use and substance use disorders in adolescents. In the 8th and 9th grade, 521 adolescents completed measures assessing depressive symptoms, conduct problems, and reflective and brooding subtypes of rumination. In 12th grade, adolescents reported substance use and were administered the substance use disorders modules from the DISC. Path analyses conducted with data from 428 participants indicated that neither depression nor rumination variables significantly affected the presence of substance use. However, indirect effects of depression through reflection and brooding were differentially related to risk of developing substance use disorders, with brooding positively associated with Marijuana Use Disorders, and reflection negatively related to both Marijuana and Alcohol Use Disorders. Pathways did not differ by sex. These findings suggest that promoting self-reflection may be an effective strategy to prevent and intervene with the development of problematic substance use.

Predictors of substance use among young adults transitioning away from high school: a narrative review.

BACKGROUND: Young adulthood has been shown to be a time of increased substance use. Yet, not enough is known about which factors contribute to initiation and progression of substance use among young adults specifically during the transition year away from high school. OBJECTIVES: A narrative review was undertaken to increase understanding of the predictors of changes in use of tobacco, alcohol, cannabis, other illicit drugs, and mental health problems among young adults during the transition period after high school. METHODS: A review of academic literature examining predictors of the use of tobacco, alcohol and cannabis, and co-morbidities (e.g., co-occurring substance use and/or mental health issues) among young adults transitioning from high school to post-secondary education or the workforce. RESULTS: Twenty six studies were included in the review. The majority of the studies (19) examined substance use during the transition from high school to post-secondary settings. Seven studies examined substance use in post-secondary settings. The studies consistently found that substance use increases among young adults as they transition away from high school. During the transition away from high school, common predictors of substance use include substance use in high school, and peer influence. Common predictors of substance use in post-secondary education include previous substance use, peer influence, psychological factors and mental health issues. Conclusions/Importance: Further research on social contextual influences on substance use, mental health issues, gender differences and availability of substances during the transition period is needed to inform the development of new preventive interventions for this age group.