Young adult sequelae of adolescent cannabis use: an integrative analysis

The consequences of chronic cannabis smoking in vulnerable adolescents

Cannabis, like the mythic shape-shifter, presents in various guises, morphing with the perspective and context of the observer. Arguments about cannabis are confused by a myriad of debates-medical, social, ethical and political-as if a single conceptual umbrella can capture the variety and granularity of marijuana-related issues. This paper responds to marijuana use as it is commonly practised by youth in Australia. It has little to say about synthetic cannabinoids, specific medicinal cannabinoids, or medicinal properties of marijuana. We address those adolescents genetically and environmentally vulnerable to mental illness, with specific emphasis on indigenous and neurodevelopmentally impaired young people who show patterns of usage and response very different to adults and more resilient members of the population. Specifically, the practice of mixing tobacco with marijuana by aboriginal youth, and the resultant coalition of dependencies, will likely presage a rise in pulmonary and central nervous system pathology over the coming decades. Aboriginal youth begin using earlier, persist longer, and take greater quantities of cannabis than non-indigenous youth. This paper recommends practical interventions to reduce the multiple health consequences of chronic cannabis use in young people, especially indigenous young people.

Major depressive disorder, suicidal thoughts and behaviours, and cannabis involvement in discordant twins: a retrospective cohort study

BACKGROUND

Early and frequent cannabis use are associated with an increased likelihood of major depressive disorder (MDD) as well as suicidal thoughts and behaviours. We identify associations between aspects of cannabis use, MDD, and suicidal thoughts and behaviours and examine whether such associations persist after accounting for those predisposing factors, including genetic liability and early family environment, that are shared by identical twins who are discordant for cannabis exposure. Any residual association in such identical pairs might be indicative of individual-specific pathways that might be of a causal nature.

METHODS

We did a logistic regression analysis of cannabis use from retrospective data on same-sex male and female twin pairs drawn from 3 studies that had recruited twins from the Australian Twin Registry, 1992-93 (sample 1), 1996-2000 (sample 2), and 2005-09 (sample 3). We studied associations between early use and frequent use of cannabis and MDD, suicidal ideation (ever and persistent), and suicide plan and attempt in the full sample as well as in pairs of monozygotic and dizygotic twins that were discordant for each measure of cannabis involvement at a single timepoint. Significant monozygotic associations were further adjusted for covariates, such as early alcohol or nicotine use, early dysphoric or anhedonic mood, conduct disorder, and childhood sexual abuse. Interactions between each cannabis measure and sex, sample or study effects, and birth year category were also examined as covariates.

FINDINGS

In 13 986 twins (6181 monozygotic and 7805 dizygotic), cannabis use ranged from 1345 (30·4%) of 4432 people in sample 1 to 2275 (69·0%) of 3299 in sample 3. Mean age of first cannabis use ranged from 17·9 years (SD 3·3) in sample 3 to 21·1 years (5·2) in sample 1, and frequent use (≥100 times) was reported by 214 (15·9%) of 1345 users in sample 1 and 499 (21·9%) of 2275 in sample 3. The prevalence of suicidal ideation ranged from 1102 (24·9%) of 4432 people in sample 1 to 1644 (26·3%) of 6255 people in sample 2 and 865 (26·2%) of 3299 people in sample 3. Prevalence of MDD ranged from 901 (20·3%) people in sample 1 to 1773 (28·3%) in sample 2. The monozygotic twin who used cannabis frequently was more likely to report MDD (odds ratio 1·98, 95% CI 1·11-3·53) and suicidal ideation (2·47, 1·19-5·10) compared with their identical twin who had used cannabis less frequently, even after adjustment for covariates. For early cannabis use, the monozygotic point estimate was not significant but could be equated to the significant dizygotic estimate, suggesting a possible association with suicidal ideation.

INTERPRETATION

The increased likelihood of MDD and suicidal ideation in frequent cannabis users cannot be solely attributed to common predisposing factors.

FUNDING

National Institute on Drug Abuse, National Institutes of Health, Australian National Health and Medical Research Council.

Daily associations between cannabis motives and consumption in emerging adults

BACKGROUND

Increasing rates of cannabis use among emerging adults is a growing public health problem. Intensive longitudinal data can provide information on proximal motives for cannabis use, which can inform interventions to reduce use among emerging adults.

METHOD

As part of a larger longitudinal study, patients aged 18-25 years (N=95) recruited from an urban Emergency Department completed daily text message assessments of risk behaviors for 28days, including daily cannabis quantity and motives. Using a mixed effects linear regression model, we examined the relationships between daily quantity of cannabis consumed and motives (i.e., enhancement, social, conformity, coping, and expansion).

RESULTS

Participants were, on average, 22.0 years old (SD=2.2); 48.4% were male, 45.3% were African American, and 56.8% received public assistance. Results from the multi-level analysis (clustering day within individual), controlling for gender, race, and receipt of public assistance, indicated daily use of cannabis use for enhancement (β=0.27), coping (β=0.15), and/or social motives (β=0.34) was significantly associated with higher quantities of daily cannabis use; whereas expansion and conformity motives were not.

CONCLUSIONS

Daily data show that emerging adults who use cannabis for enhancement, social, and coping motives reported using greater quantities of cannabis. Future research should examine more comprehensive cannabis motives (e.g., boredom, social anxiety, sleep) and test tailored interventions focusing on alternative cognitive/behavioral strategies to address cannabis motives.

Implementing the teen marijuana check-up in schools-a study protocol

BACKGROUND

Substance misuse is now encountered in settings beyond addiction specialty care, with schools a point-of-contact for student access to behavioral health services. Marijuana is a leading impetus for adolescent treatment admissions despite declining risk perception, for which the Teen Marijuana Check-Up (TMCU)-a tailored adaptation of motivational enhancement therapy-offers an efficacious service option. To bridge the knowledge gap concerning effective and affordable technical assistance strategies for implementing empirically supported services, the described trial will test such a strategy to facilitate school-based TMCU implementation.

METHODS

A type II effectiveness/implementation hybrid trial will test a novel strategy for a TMCU purveyor to provide technical assistance on an 'as-needed' basis when triggered by a fidelity drift alarm bell, compared to resource-intensive 'gold-standard' technical assistance procedures of prior efficacy trials. Trial procedures adhere to the EPIS framework as follows: (1) initial mixed-method exploration of the involved school contexts and identification of TMCU interventionist candidates in elicitation interviews; (2) interventionist preparation via a formally evaluated training process involving a two-day workshop and sequence of three training cases; (3) post-training implementation for 24 months for which trained interventionists are randomized to 'as-needed' or 'gold-standard' technical assistance and self-referring students randomized (in 2:1 ratio) to TMCU or waitlist/control; and (4) examination of TMCU sustainment via interventionist completion of biannual outcome assessments, cost analyses, and exit interviews. Hypothesized effects include non-differential influence of the competing technical assistance methods on both TMCU fidelity and intervention effectiveness, with lesser school costs for the 'as-needed' than 'gold-standard' technical assistance and greater reduction in the frequency of marijuana use expected among TMCU-exposed students relative to those assigned to waitlist/control.

DISCUSSION

This trial-occurring in Washington state as legislative, fiscal, and sociocultural forces converge to heighten exposure of American adolescents to marijuana-related harms-is set to advance understanding of best implementation practices for this and other efficacious, school-based interventions through examination of a data-driven technical assistance method. If shown to be clinically useful and affordable, the concept of a fidelity drift alarm could be readily translated to other empirically supported services and in other health settings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03111667 registered 7 April 2017.

Cannabis use in early adolescence is associated with higher negative schizotypy in females

The current study examined the relationship between early onset cannabis use (before age 16) and different schizotypy dimensions, and whether gender moderates these associations. Participants were 162 cannabis users, aged 15-24 years, who completed an online assessment examining alcohol and other drug use, psychological distress, and schizotypy. Participants were divided according to whether or not they had started using cannabis before the age of 16 (early onset=47; later onset=115) and gender (males=66; females=96). The interaction between gender and onset group was significantly associated with the dimension of introvertive anhedonia. Follow-up analyses showed that early onset cannabis use was associated with higher levels of introvertive anhedonia in females only. The current findings suggest that gender is an important moderator in the association between early onset cannabis use, schizotypy, and possibly, psychosis risk.

DSM-5 cannabis use disorder, substance use and DSM-5 specific substance-use disorders: Evaluating comorbidity in a population-based sample

Cannabis use disorder (CUD) is frequently associated with concurrent substance use and/or comorbid substance use disorders (SUDs); however there is little specificity with regard to commonly abused individual drug types/classes. This study therefore aimed to provide insight into the degree of these co-occurring relationships across several specific newer and older generation illicit and prescription drugs. 36,309 adults aged 18+ from wave 3 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC-III) were assessed. Weighted cross-tabulations and multivariable logistic regression analyses were used to evaluate comorbidity between current DSM-5 CUD, substance use and DSM-5 SUD. Current DSM-5 CUD is associated with greater lifetime use of all examined drug classes, and previous 12-month use of several newer-class illicit and prescription stimulant-based substances (all p< 0.05). Current DSM-5 CUD was similarly associated with increased incidence of a range of DSM-5 SUDs and was independently associated with concurrently reporting current DSM-5; sedative (Adjusted OR= 5.1, 95%CI 2.9-9.0), cocaine (AOR= 9.3, 95%CI 5.6-15.5), stimulant (AOR= 4.3, 95%CI 2.3-7.9), club drug (AOR= 16.1, 95%CI 6.3-40.8), opioid (AOR= 4.6, 95%CI 3.0-6.8) and alcohol-use disorder (AOR= 3.0, 95%CI 2.5-3.7); but not heroin or 'other' drug use disorder (both p>0.05). High comorbidity exists between DSM-5 CUD and many specific DSM-5 SUDs. Newer-class illicit and prescription stimulant-based drug use disorders are overrepresented among those with DSM-5 CUD. These findings underscore the need for tailored treatment programs for those presenting with DSM-5 CUD, and for greater treatment specification where poly-drug use is evident.

Lower-Risk Cannabis Use Guidelines: A Comprehensive Update of Evidence and Recommendations

BACKGROUND

Cannabis use is common in North America, especially among young people, and is associated with a risk of various acute and chronic adverse health outcomes. Cannabis control regimes are evolving, for example toward a national legalization policy in Canada, with the aim to improve public health, and thus require evidence-based interventions. As cannabis-related health outcomes may be influenced by behaviors that are modifiable by the user, evidence-based Lower-Risk Cannabis Use Guidelines (LRCUG)-akin to similar guidelines in other health fields-offer a valuable, targeted prevention tool to improve public health outcomes.

OBJECTIVES

To systematically review, update, and quality-grade evidence on behavioral factors determining adverse health outcomes from cannabis that may be modifiable by the user, and translate this evidence into revised LRCUG as a public health intervention tool based on an expert consensus process.

SEARCH METHODS

We used pertinent medical search terms and structured search strategies, to search MEDLINE, EMBASE, PsycINFO, Cochrane Library databases, and reference lists primarily for systematic reviews and meta-analyses, and additional evidence on modifiable risk factors for adverse health outcomes from cannabis use.

SELECTION CRITERIA

We included studies if they focused on potentially modifiable behavior-based factors for risks or harms for health from cannabis use, and excluded studies if cannabis use was assessed for therapeutic purposes.

DATA COLLECTION AND ANALYSIS

We screened the titles and abstracts of all studies identified by the search strategy and assessed the full texts of all potentially eligible studies for inclusion; 2 of the authors independently extracted the data of all studies included in this review. We created Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow-charts for each of the topical searches. Subsequently, we summarized the evidence by behavioral factor topic, quality-graded it by following standard (Grading of Recommendations Assessment, Development, and Evaluation; GRADE) criteria, and translated it into the LRCUG recommendations by the author expert collective on the basis of an iterative consensus process.

MAIN RESULTS

For most recommendations, there was at least "substantial" (i.e., good-quality) evidence. We developed 10 major recommendations for lower-risk use: (1) the most effective way to avoid cannabis use-related health risks is abstinence, (2) avoid early age initiation of cannabis use (i.e., definitively before the age of 16 years), (3) choose low-potency tetrahydrocannabinol (THC) or balanced THC-to-cannabidiol (CBD)-ratio cannabis products, (4) abstain from using synthetic cannabinoids, (5) avoid combusted cannabis inhalation and give preference to nonsmoking use methods, (6) avoid deep or other risky inhalation practices, (7) avoid high-frequency (e.g., daily or near-daily) cannabis use, (8) abstain from cannabis-impaired driving, (9) populations at higher risk for cannabis use-related health problems should avoid use altogether, and (10) avoid combining previously mentioned risk behaviors (e.g., early initiation and high-frequency use).

AUTHORS' CONCLUSIONS

Evidence indicates that a substantial extent of the risk of adverse health outcomes from cannabis use may be reduced by informed behavioral choices among users. The evidence-based LRCUG serve as a population-level education and intervention tool to inform such user choices toward improved public health outcomes. However, the LRCUG ought to be systematically communicated and supported by key regulation measures (e.g., cannabis product labeling, content regulation) to be effective. All of these measures are concretely possible under emerging legalization regimes, and should be actively implemented by regulatory authorities. The population-level impact of the LRCUG toward reducing cannabis use-related health risks should be evaluated. Public health implications. Cannabis control regimes are evolving, including legalization in North America, with uncertain impacts on public health. Evidence-based LRCUG offer a potentially valuable population-level tool to reduce the risk of adverse health outcomes from cannabis use among (especially young) users in legalization contexts, and hence to contribute to improved public health outcomes.

Can we make cannabis safer?

Cannabis use and related problems are on the rise globally alongside an increase in the potency of cannabis sold on both black and legal markets. Additionally, there has been a shift towards abandoning prohibition for a less punitive and more permissive legal stance on cannabis, such as decriminalisation and legalisation. It is therefore crucial that we explore new and innovative ways to reduce harm. Research has found cannabis with high concentrations of its main active ingredient, δ-9-tetrahydrocannabinol (THC), to be more harmful (in terms of causing the main risks associated with cannabis use, such as addiction, psychosis, and cognitive impairment) than cannabis with lower concentrations of THC. By contrast, cannabidiol, which is a non-intoxicating and potentially therapeutic component of cannabis, has been found to reduce the negative effects of cannabis use. Here, we briefly review findings from studies investigating various types of cannabis and discuss how future research can help to better understand and reduce the risks of cannabis use.

Alcohol, cannabis and other drugs and subsequent suicide ideation and attempt among young Mexicans

OBJECTIVE

To report results from a follow-up study of alcohol, cannabis and other drugs on suicidal behavior.

METHOD

We estimated prospective associations of substance use as a risk factor for incident suicide ideation and attempt, from a follow-up conducted in 2013 (n = 1071) of the original Mexican Adolescent Mental Health Survey conducted in 2005.

RESULTS

Cannabis use before age 15 (ideation risk ratio (RR) = 3.97; 95% confidence interval (CI) = 1.43-11.03; attempt RR = 5.23; 95% CI = 1.17-23.32), early onset of DSM-IV drug use disorder (DUD) among cannabis users (ideation RR = 3.30; 95% CI = 1.11-9.84; attempt RR = 4.14; 95% CI = 1.28-13.36), high frequency of cannabis use (RR for attempts = 4.60; 1.03-20.60) and recent DSM-IV-DUD among cannabis users (RR for attempts = 4.74; 1.09-20.57) increased the RR. For "other drug use", significant results were found among those with high frequency use of other drugs such that they had a higher RR of suicide attempt (5.04; 1.03-24.64). For alcohol, only those who initiated alcohol before age 15 had higher RRs of suicide attempt (1.79; 1.00-3.20).

DISCUSSION

Those who used cannabis at an early age, early onset of DSM-IV-DUD, and those with heavy cannabis use and recent DSM-IV-DUD among cannabis users in the last 12-months had increased risk of suicide ideation and attempt. Drugs other than cannabis showed some of these associations, but to a lesser degree. Prevention of substance use and treatment of those already engaged in drug use, by decreasing suicide ideation and attempt, may help to prevent suicide in Mexico.

Developing harm reduction in the context of youth substance use: insights from a multi-site qualitative analysis of young people's harm minimization strategies

BACKGROUND

Youth substance use programming and educational strategies are frequently informed by prevention approaches that emphasize abstinence goals, which often do not resonate with youth in their lack of acknowledgment of young people's social context and how young people perceive positive effects of substance use. Further, approaches to drug prevention have been critiqued as adopting a one-size-fits-all approach and therefore inadequate in addressing substance use in the context of population variation and inequities. In response to the limitations of current approaches to prevention, programming informed by harm reduction principles that aims to minimize harms without requiring abstinence is emergent in school settings. However, youth perspectives informing harm reduction are limited in both research and program development.

METHODS

This paper draws on data from the Researching Adolescent Distress and Resilience (RADAR) study, which utilized an ethnographic approach to bring youth voice to the literature on mental health and substance use. Qualitative data collection included individual interviews (n = 86) with young people aged 13-18 across three communities-representing urban, suburban, and rural geographies-in British Columbia, Canada. A multi-site qualitative analysis of interview data was conducted to identify themes across and within each research site.

RESULTS

Across all three sites, young people's individual experiences of substance use were shaped by geographic, socio-cultural, and political contexts, with youth describing their use in relation to the nature of substance use in peer groups and in the broader community. To manage their own substance use and reduce related harms, youth employed a variety of ad hoc harm minimization strategies that were reflective of their respective contexts.

CONCLUSIONS

The findings from this study suggest the importance of harm reduction approaches that are contextually relevant and responsive to the lived experiences of youth. Youth perspectives in the development of harm reduction programming are needed to ensure that approaches are relatable and meaningful to young people, and effective for promoting the minimization of substance-related harms.

Patterns of cannabis use during adolescence and their association with harmful substance use behaviour: findings from a UK birth cohort

BACKGROUND

Evidence on the role of cannabis as a gateway drug is inconsistent. We characterise patterns of cannabis use among UK teenagers aged 13-18 years, and assess their influence on problematic substance use at age 21 years.

METHODS

We used longitudinal latent class analysis to derive trajectories of cannabis use from self-report measures in a UK birth cohort. We investigated (1) factors associated with latent class membership and (2) whether latent class membership predicted subsequent nicotine dependence, harmful alcohol use and recent use of other illicit drugs at age 21 years.

RESULTS

5315 adolescents had three or more measures of cannabis use from age 13 to 18 years. Cannabis use patterns were captured as four latent classes corresponding to 'non-users' (80.1%), 'late-onset occasional' (14.2%), 'early-onset occasional' (2.3%) and 'regular' users (3.4%). Sex, mother's substance use, and child's tobacco use, alcohol consumption and conduct problems were strongly associated with cannabis use. At age 21 years, compared with the non-user class, late-onset occasional, early-onset occasional and regular cannabis user classes had higher odds of nicotine dependence (OR=3.5, 95% CI 0.7 to 17.9; OR=12.1, 95% CI 1.0 to 150.3; and OR=37.2, 95% CI 9.5 to 144.8, respectively); harmful alcohol consumption (OR=2.6, 95% CI 1.5 to 4.3; OR=5.0, 95% CI 2.1 to 12.1; and OR=2.6, 95% CI 1.0 to 7.1, respectively); and other illicit drug use (OR=22.7, 95% CI 11.3 to 45.7; OR=15.9, 95% CI 3.9 to 64.4; and OR=47.9, 95% CI 47.9 to 337.0, respectively).

CONCLUSIONS

One-fifth of the adolescents in our sample followed a pattern of occasional or regular cannabis use, and these young people were more likely to progress to harmful substance use behaviours in early adulthood.

Longitudinal Studies on the Etiology of Cannabis Use Disorder: A Review

PURPOSE OF REVIEW

This review summarizes the literature to date that has capitalized on the longitudinal research study framework in order to elucidate the etiology of cannabis use disorders (CUDs).

RECENT FINDINGS

The studies are mixed with respect to reliable predictors of CUD development. Of the studies outlined, the most consistently indicated risk factors for CUD development include: male sex, past cannabis and other substance use (especially tobacco), and the presence of pre/comorbid psychopathology (especially mood disorders). Social motives and peer involvement may also play a role in this transition. Many of these CUD risk factors appear to be distinct from other factors linked with overall cannabis use.

SUMMARY

CUD development is likely the product of interactions between biological, psychological, social, and environmental factors. However, many more well-planned and developmentally sensitive prospective studies are needed to identify specific and reliable risk factors for CUD development.

The Role of Public Health in Combatting Synthetic Cannabinoid Use in Adolescents

As the country struggles to address an epidemic of alcohol and drug overdose, a wide-ranging category of chemical substances known as synthetic drugs have provoked a new sense of public urgency over the past decade. Synthetic cannabinoids, a heterogeneous and evolving set of synthetic compounds that act on endogenous cannabinoid receptors, have become particularly popular among adolescents due to their relative ease of access and reputation as a "legal high." The Baltimore City Health Department has worked to combat the recent surge in synthetic drug use through a major public awareness campaign, legislative reform, and retailer engagement and compliance initiative. In doing so, the city has built a coalition of clinicians, advocates, retailers, educators, legislators, and community members to fight synthetic cannabinoid use in Baltimore City. In this commentary piece, we offer strategies from our work and from that of our colleagues across the country for clinicians and communities fighting to stem the tide of recreational synthetic cannabinoid use.

Recreational stimulants, herbal, and spice cannabis: The core psychobiological processes that underlie their damaging effects

AIMS

Recreational drugs are taken for their positive mood effects, yet their regular usage damages well-being. The psychobiological mechanisms underlying these damaging effects will be debated.

METHODS

The empirical literature on recreational cannabinoids and stimulant drugs is reviewed. A theoretical explanation for how they cause similar types of damage is outlined.

RESULTS

All psychoactive drugs cause moods and psychological states to fluctuate. The acute mood gains underlie their recreational usage, while the mood deficits on withdrawal explain their addictiveness. Cyclical mood changes are found with every central nervous system stimulant and also occur with cannabis. These mood state changes provide a surface index for more profound psychobiological fluctuations. Homeostatic balance is altered, with repetitive disturbances of the hypothalamic-pituitary-adrenal axis, and disrupted cortisol-neurohormonal secretions. Hence, these drugs cause increased stress, disturbed sleep, neurocognitive impairments, altered brain activity, and psychiatric vulnerability. Equivalent deficits occur with novel psychoactive stimulants such as mephedrone and artificial "spice" cannabinoids. These psychobiological fluctuations underlie drug dependency and make cessation difficult. Psychobiological stability and homeostatic balance are optimally restored by quitting psychoactive drugs.

CONCLUSIONS

Recreational stimulants such as cocaine or MDMA (3.4-methylenedioxymethamphetamine) and sedative drugs such as cannabis damage human homeostasis and well-being through similar core psychobiological mechanisms.

Evidence for Sex Convergence in Prevalence of Cannabis Use: A Systematic Review and Meta-Regression

OBJECTIVE

Generally, cannabis use has been more prevalent in men than in women. However, emerging evidence suggests that the prevalence of cannabis use is converging among males and females from recent cohorts. This study aimed to systematically summarize published literature on birth cohort changes in male-to-female ratios in prevalence of cannabis use.

METHOD

Twenty-two studies with a median sample size of 85,052 were identified for inclusion. Data were collected between 1979 and 2010, representing birth cohorts from 1936 to 1999. For quantitative synthesis, male-to-female ratios in prevalence of any cannabis use were calculated for all 5-year birth cohorts available, generating 348 separate ratios among birth cohorts from 1941 to 1995 in 30 countries. Random-effects meta-analyses generated pooled sex ratios, stratified by 5-year birth cohorts.

RESULTS

Of the 22 included studies, 10 reported some evidence of sex convergence in cannabis use among more recent cohorts. Quantitative synthesis found that the ratio of cannabis use prevalence in males and females decreased significantly from 2.0 among cohorts born in 1941 to 1.3 among those born in 1995.

CONCLUSIONS

Findings support the narrowing sex gap in the prevalence of cannabis use. Results are concordant with a broader literature demonstrating sex convergence in prevalence of other substance use, particularly alcohol use and related harms. Both young women and men should be the target of prevention and early intervention efforts. Future research in more diverse global settings, especially in low- and middle-income countries, would enhance the international scope of the findings.

Reciprocal relationships between substance use and disorders and suicidal ideation and suicide attempts in the Collaborative Study of the Genetics of Alcoholism

BACKGROUND

Substance use and misuse and suicidal thoughts and behaviors tend to co-occur. The purpose of this study was to examine whether (a) suicidal ideation and attempt are related to onset of alcohol, nicotine and cannabis use and dependence; (b) early use of alcohol, nicotine and cannabis is associated with onset of suicidal ideation and attempt; and (c) whether these associations persist while controlling for covariates, such as family history of alcohol problems, major depression and other internalizing and externalizing disorders.

METHODS

The prospective cohort of the Collaborative Study of the Genetics of Alcoholism (COGA; N=3277) was used. Cross-sectional and discrete time logistic regression (i.e. survival) analyses examined associations between suicidal ideation and attempt and onset of alcohol, nicotine and cannabis use and dependence. Survival models also examined whether individual early substance use was related to onset of ideation and attempt.

RESULTS

Ideation was related to 0.71-0.77 odds of onset of subsequent alcohol, nicotine and cannabis use. Attempt was associated with 1.44-1.61 odds of later alcohol, nicotine and cannabis dependence, even after accounting for covariates. Evidence for early substance use being related to subsequent onset of ideation or attempt was limited. Several sex and race differences emerged.

LIMITATIONS

The sample was ascertained for family history of alcoholism; not all participants had been followed up allowing for censored observations; reporting bias.

CONCLUSION

Suicide attempts are associated with increased likelihood of onset of substance dependence.

Building smart cannabis policy from the science up

Social attitudes and cultural norms around the issue of substance abuse are shifting rapidly around the world, leading to complex and unpredictable consequences. On the positive side, efforts to more intensely disseminate the scientific evidence for the many connections between chronic substance use and the emergence of measurable and discrete brain dysfunctions, has ushered in an evolving climate of acceptance and a new era of improved access to more effective interventions, at least in the United States. On the negative side, there has been a steady erosion in the public perception of the harms associated with the use of popular drugs, especially cannabis. This worrisome trend has sprouted at the convergence of several forces that have combined, more or less fortuitously, to effectively change long-standing policies away from prohibition and toward decriminalization or legalization. These forces include the outsized popularity of the cannabis plant among recreational users, the unflagging campaign by corporate lobbyists and patient advocates to mainstream its medicinal use, and the honest realization in some quarters of the deleterious impact of the drug war and its draconian cannabis laws, in particular, on society's most vulnerable populations. Updating drug policies is a desirable goal, and significant changes may indeed be warranted. However, there is a real concern when policy changes are hurriedly implemented without the required input from the medical, scientific, or policy research communities. Regardless of how well intentioned, such initiatives are bound to magnify the potential for unintended adverse consequences in the form of far ranging health and social costs. To minimize this risk, science must be front and center in this important policy debate. Here, we review the state of the science on cannabis and cannabinoid health effects, both adverse and therapeutic. We focus on the prevalence of use in different populations, the mechanisms by which cannabis exerts its effects (i.e., via the endocannabinoid system), and the double-edged potential of this system to inspire new medications, on one hand, and to cause short and long term harmful effects on the other. By providing knowledge of cannabis' broad ranging effects, we hope to enable better decision making regarding cannabis legislation and policy implementation.

Evidence for the Risks and Consequences of Adolescent Cannabis Exposure

OBJECTIVE

This review of the scientific literature examines the potential adult sequelae of exposure to cannabis and related synthetic cannabinoids in adolescence. We examine the four neuropsychiatric outcomes that are likely most vulnerable to alteration by early cannabinoid use, as identified within both the clinical and preclinical research: cognition, emotional functioning, risk for psychosis, and addiction.

METHOD

A literature search was conducted through PubMed, PsychInfo, and Google Scholar with no publication date restrictions. The search terms used were "adolescent" and "adult," and either "cannabis," "marijuana," "delta-9-tetra-hydrocannabinol," or "cannabinoid," which was then crossed with one or more of the following terms: "deficit," "impairment," "alteration," "long-term," "persistent," "development," "maturation," and "pubescent."

RESULTS

The majority of the clinical and preclinical data point to a strong correlation between adolescent cannabinoid exposure and persistent, adverse neuropsychiatric outcomes in adulthood. Although the literature supports the hypothesis that adolescent cannabis use is connected to impaired cognition and mental health in adults, it does not conclusively demonstrate that cannabis consumption alone is sufficient to cause these deficits in humans. The animal literature, however, clearly indicates that adolescent-onset exposure to cannabinoids can catalyze molecular processes that lead to persistent functional deficits in adulthood, deficits that are not found to follow adult-onset exposure and that model some of the adverse outcomes reported in humans among adult populations of early-onset cannabis users.

CONCLUSION

Based on the data in the current literature, a strong association is found between early, frequent, and heavy adolescent cannabis exposure and poor cognitive and psychiatric outcomes in adulthood, yet definite conclusions cannot yet be made as to whether cannabis use alone has a negative impact on the human adolescent brain. Future research will require animal models and longitudinal studies to be carefully designed with a focus on integrating assessments of molecular, structural, and behavioral outcomes in order to elucidate the full range of potential adverse and long-term consequences of cannabinoid exposure in adolescence.

Maelstrom Research guidelines for rigorous retrospective data harmonization

Background

It is widely accepted and acknowledged that data harmonization is crucial: in its absence, the co-analysis of major tranches of high quality extant data is liable to inefficiency or error. However, despite its widespread practice, no formalized/systematic guidelines exist to ensure high quality retrospective data harmonization.

Methods

To better understand real-world harmonization practices and facilitate development of formal guidelines, three interrelated initiatives were undertaken between 2006 and 2015. They included a phone survey with 34 major international research initiatives, a series of workshops with experts, and case studies applying the proposed guidelines.

Results

A wide range of projects use retrospective harmonization to support their research activities but even when appropriate approaches are used, the terminologies, procedures, technologies and methods adopted vary markedly. The generic guidelines outlined in this article delineate the essentials required and describe an interdependent step-by-step approach to harmonization: 0) define the research question, objectives and protocol; 1) assemble pre-existing knowledge and select studies; 2) define targeted variables and evaluate harmonization potential; 3) process data; 4) estimate quality of the harmonized dataset(s) generated; and 5) disseminate and preserve final harmonization products.

Conclusions

This manuscript provides guidelines aiming to encourage rigorous and effective approaches to harmonization which are comprehensively and transparently documented and straightforward to interpret and implement. This can be seen as a key step towards implementing guiding principles analogous to those that are well recognised as being essential in securing the foundational underpinning of systematic reviews and the meta-analysis of clinical trials.

Cannabis Use and Cannabis Use Disorders Among Youth in the United States, 2002-2014

OBJECTIVE

To examine trends in past-year cannabis use (CU) and cannabis use disorders (CUD) among youth in the United States, when related changes began, and factors associated with these changes.

METHODS

This study used data from 288,300 persons aged 12-17 years who participated in the 2002-2014 National Survey on Drug Use and Health. Descriptive analyses and bivariable and multivariable logistic regressions were applied (using the year 2002 as the reference group for most analyses).

RESULTS

The prevalence of past-year CU among youth decreased from 15.8% in 2002 to 13.1% in 2014 (this downward trend occurred during 2002-2007 only [β = -0.0540, P < .0001]). Among youth cannabis users, the prevalence of past-year CUD decreased from 27.0% in 2002 to 20.4% in 2014, with a downward trend starting in 2011 (β = -0.0970, P = .0001). During 2002-2014, the prevalence of past-year tobacco use and alcohol use decreased and prevalences of past-year CU increased among tobacco users and among alcohol users. Our multivariable results suggest that declines in past-year tobacco use (but not alcohol use) among youth were associated with declines in past-year CU during 2010-2014. Past-year CU and CUD were higher among racial/ethnic minorities (except for non-Hispanic Asians and Hawaiians/Pacific Islanders for CU) than non-Hispanic whites and were similar between male and female youth during 2002-2014.

CONCLUSIONS

In the United States, compared to 2002, even after adjusting for covariates, CU decreased among youth during 2005-2014, and CUD declined among youth cannabis users during 2013-2014. Associations between declines in tobacco use and decreased CU suggest the importance of tobacco use control and prevention among youth.

Progression in substance use initiation: A multilevel discordant monozygotic twin design

Considerable attention has been paid to the "gateway" pattern of drug use initiation in which individuals progress from tobacco and alcohol use to cannabis and other illicit drugs. The extent to which this sequence reflects a causal impact of licit substance use on illicit substance involvement remains unclear. Clarifying the mechanisms underlying substance use initiation may help inform our understanding of risk for psychopathology, as increasing research is demonstrating associations between initiation patterns and heavier involvement. This study examined patterns of substance use initiation using a discordant twin design. Participants were 3,476 monozygotic twins (37% male) from the Australian Twin Registry who reported on their ages of tobacco, alcohol, and cannabis initiation. Multilevel proportional hazard regression models were used to (a) estimate within-twin-pair and between-twin-pair contributions to associations between the ages of onset of different drugs; and (b) examine whether the magnitude of effects differed as a function of the order of substance use initiation. Finding significant effects within twin pairs would support the hypothesis that the age of initiation of a substance causally influences the age of initiation of a subsequent substance. Finding significant effects between twin pairs would support the operation of familial influences that explain variation in the ages of initiation of multiple drugs. Within-twin-pair effects for typical patterns were modest. When initiation was atypical, however, larger within-twin-pair effects were observed and causal influences were more strongly implicated. Results support the utility of examining the timing and ordering of substance use initiation within sophisticated, genetically informative designs.

Long-term consequences of adolescent cannabis use: Examining intermediary processes

BACKGROUND

In the United States, perceptions of marijuana's acceptability are at an all-time high, risk perceptions among youth are low, and rates are rising among Black youth. Thus, it is imperative to increase the understanding of long-term effects of adolescent marijuana use and ways to mitigate adverse consequences.

OBJECTIVES

To identify the midlife consequences of heavy adolescent marijuana use and the mechanisms driving effects among a Black, urban population.

METHODS

This study analyzed the propensity score-matched prospective data from the Woodlawn Study, a community cohort study of urban Black youth followed from ages 6-42. After matching the 165 adolescents who used marijuana heavily to 165 non-heavy/nonusers on background confounders to reduce selection effects (64.5% male), we tested the association of heavy marijuana use by age 16 with social, economic, and physical and psychological health outcomes in midlife and the ability of adult drug trajectories (marijuana, cocaine, and heroin use from ages 17-42) and school dropout to mediate effects.

RESULTS

Heavy adolescent marijuana use was associated with an increased risk of being poor and of being unmarried in midlife. Marijuana use also predicted lower income and greater anxious mood in midlife. Both adult drug use trajectories and school dropout significantly mediated socioeconomic effects but not marital or anxious mood outcomes.

CONCLUSION

Heavy adolescent marijuana use seems to set Black, urban youth on a long-term trajectory of disadvantage that persists into midlife. It is critical to interrupt this long-term disadvantage through the prevention of heavy adolescent marijuana use, long-term marijuana and other drug use, and school dropout.

The effects of Δ9-tetrahydrocannabinol on the dopamine system

The effects of Δ9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, are a pressing concern for global mental health. Patterns of cannabis use are changing drastically owing to legalization, the availability of synthetic analogues (commonly termed spice), cannavaping and an emphasis on the purported therapeutic effects of cannabis. Many of the reinforcing effects of THC are mediated by the dopamine system. Owing to the complexity of the cannabinoid-dopamine interactions that take place, there is conflicting evidence from human and animal studies concerning the effects of THC on the dopamine system. Acute THC administration causes increased dopamine release and neuron activity, whereas long-term use is associated with blunting of the dopamine system. Future research must examine the long-term and developmental dopaminergic effects of THC.

The association between cannabis use and suicidality among men and women: A population-based longitudinal study

BACKGROUND

Evidence regarding the role of sex differences in the association between cannabis use and suicidality is lacking. We explored sex differences in the bidirectional association between cannabis use and suicidality in a 3-year longitudinal study.

METHODS

Data were drawn from waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Bidirectional analyses were conducted separately by sex, exploring incidence of suicidality among cannabis users (n=963 vs. 30,586 non-users) as well as initiation of cannabis use among suicidal individuals (n=1805 vs. 25,729 non-suicidal). Cannabis use was categorized based on frequency of use. Multivariate logistic regression analyses controlling for multiple covariates were conducted.

RESULTS

Cannabis use was significantly associated with increased incidence of suicidality among men (Adjusted Odds Ratio [AOR] for any cannabis use =1.91[1.02-3.56]) but not among women (AOR=1.19[0.64-2.20]). Daily cannabis use was significantly associated with increased incidence of suicidality among men (AOR=4.28[1.32-13.82]) but not among women (AOR=0.75[0.28-2.05]). Conversely, baseline suicidality was associated with initiation of cannabis use among women (AOR=2.34[1.42-3.87]) but not among men (AOR=1.10[0.57-2.15]). Separate analyses of suicidal ideation and suicide attempts demonstrated a significant association between cannabis use and subsequent incidence of suicidal ideation in men, and a significant association between baseline suicidal ideation and subsequent initiation of cannabis use in women. No significant association was found for the bidirectional association between cannabis use and suicide attempts in either sex.

LIMITATIONS

Suicidality was assessed only in individuals reporting depressed mood and/or anhedonia.

CONCLUSIONS

Our findings support a longitudinal association between heavy cannabis use and the incidence of suicidality in men, but not in women. Conversely, baseline suicidality is longitudinally associated with the initiation of cannabis use in women, but not in men. This may have implications on clinical and social aspects of cannabis use and merit further research into the unique effects of sex differences on cannabis induced psychopathology.

Definitions of Risky and Problematic Cannabis Use: A Systematic Review

Although cannabis is widely used, it remains unclear which consumption patterns are more likely to produce future consequences (risky/hazardous use) or current damage (problematic/harmful use). This unresolved issue contributes to cannabis public health implications. In order to facilitate further consensus, this review analyzes previously used definitions in the literature.

METHODS

This systematic review was performed following the PRISMA guidelines. Articles published before October 2015 in the Medline, Scopus-Elsevier, ISI-Web of Knowledge and Cochrane databases and fulfilling a-priori decided criteria were retrieved. Definitions in preselected websites of national and international organizations addressing drug problems were also included.

RESULTS

Definitions identified in articles (n = 46) and official websites (n = 3) widely varied from each other. Weekly cannabis use was mostly considered risky. Problematic cannabis use was mostly described with the Cannabis Abuse and Screening Test. Evidence-based definitions as well as information on quantities consumed, time-frames and special considerations for risky groups were very limited.

CONCLUSIONS

Working on official definitions is highly necessary as criteria used remain incomplete, leading to increased confusion in the field. Recommendations to improve existing definitions are given.

Marijuana use and service utilization among adolescents 7 years post substance use treatment

BACKGROUND

In an environment of increasingly liberal attitudes towards marijuana use and legalization, little is known about long-term trajectories of marijuana use among clinical samples of adolescents, and how these trajectories relate to health services utilization over time.

METHODS

Latent growth curve analysis was used to identify distinct trajectories of marijuana use in a clinical sample of adolescents (N=391) over 7 years post substance use treatment in an integrated health system. We examined psychiatric problems and polysubstance use associated with the identified trajectory groups using general linear models. Nonlinear mixed-effects logistic regressions were used to examine associations between health services use and the trajectory groups.

RESULTS

We identified three marijuana use trajectory groups: (1) Abstinent (n=117); (2) Low/Stable use (n=174); and (3) Increasing use (n=100). Average externalizing and anxiety/depression scores were significantly lower over time for the Abstinent group compared to the Increasing and Low/Stable groups. The Low Stable and the Increasing group had fewer psychiatric visits over time (p<0.05) and the Low/Stable group used more substance use treatment services over time compared with the Abstinent group (p<0.001).

CONCLUSIONS

Treated adolescents showed distinct marijuana use patterns, one of which indicated a group of adolescents at risk of increased use over time. These individuals have greater psychiatric and polysubstance use over time, but may not be accessing needed services.

The impact of adolescent exposure to medical marijuana laws on high school completion, college enrollment and college degree completion

BACKGROUND

There is concern that medical marijuana laws (MMLs) could negatively affect adolescents. To better understand these policies, we assess how adolescent exposure to MMLs is related to educational attainment.

METHODS

Data from the 2000 Census and 2001-2014 American Community Surveys were restricted to individuals who were of high school age (14-18) between 1990 and 2012 (n=5,483,715). MML exposure was coded as: (i) a dichotomous "any MML" indicator, and (ii) number of years of high school age exposure. We used logistic regression to model whether MMLs affected: (a) completing high school by age 19; (b) beginning college, irrespective of completion; and (c) obtaining any degree after beginning college. A similar dataset based on the Youth Risk Behavior Survey (YRBS) was also constructed for confirmatory analyses assessing marijuana use.

RESULTS

MMLs were associated with a 0.40 percentage point increase in the probability of not earning a high school diploma or GED after completing the 12th grade (from 3.99% to 4.39%). High school MML exposure was also associated with a 1.84 and 0.85 percentage point increase in the probability of college non-enrollment and degree non-completion, respectively (from 31.12% to 32.96% and 45.30% to 46.15%, respectively). Years of MML exposure exhibited a consistent dose response relationship for all outcomes. MMLs were also associated with 0.85 percentage point increase in daily marijuana use among 12th graders (up from 1.26%).

CONCLUSIONS

Medical marijuana law exposure between age 14 to 18 likely has a delayed effect on use and education that persists over time.

Augmenting brief interventions for adolescent marijuana users: The impact of motivational check-ins

OBJECTIVE

Brief interventions for adolescent marijuana users offered in schools reach users who would not otherwise present for treatment. The current study builds on previous trials of a school-based, 2-session motivational enhancement therapy (MET) intervention by adding periodic, brief motivational check-ins to reinforce gains and bolster motivation.

METHOD

Adolescent participants were randomly assigned to a motivational check-in (MCI; n = 128) or assessment-only check-in (ACI; n = 124) comparison condition. Both conditions received 2 sessions of MET. Participants in the MCI condition then attended 3 MET-based check-in sessions at 4, 7, and 10 months after baseline, whereas the ACI condition participants attended assessment-only check-ins at the same time points. Optional cognitive behavior therapy (CBT) sessions were available as needed for 12 months from baseline in both conditions.

RESULTS

Outcomes were assessed at 6, 9, 12, and 15 months after baseline. Participants (59% Caucasian; 68% male; mean age = 15.84) reported using marijuana on an average of 37 of the last 60 days, and 70% met diagnostic criteria for a marijuana use disorder. Both conditions were associated with reduced use and negative consequences that were sustained throughout the 15 months of follow-up. The MCI condition resulted in greater reductions at the 6 months follow-up, but differences between conditions were not found at later follow-ups, and MCI participation did not increase engagement in CBT as predicted.

CONCLUSIONS

Results replicated the efficacy of the brief intervention for adolescent marijuana use and provided mixed evidence on the utility of adding repeated check-in sessions. (PsycINFO Database Record

Adolescence as a period of vulnerability and intervention in schizophrenia: Insights from the MAM model

Adolescence is a time of extensive neuroanatomical, functional and chemical reorganization of the brain, which parallels substantial maturational changes in behavior and cognition. Environmental factors that impinge on the timing of these developmental factors, including stress and drug exposure, increase the risk for psychiatric disorders. Indeed, antecedents to affective and psychotic disorders, which have clinical and pathophysiological overlap, are commonly associated with risk factors during adolescence that predispose to these disorders. In the context of schizophrenia, psychosis typically begins in late adolescence/early adulthood, which has been replicated by animal models. Rats exposed during gestational day (GD) 17 to the mitotoxin methylazoxymethanol acetate (MAM) exhibit behavioral, pharmacological, and anatomical characteristics consistent with an animal model of schizophrenia. Here we provide an overview of adolescent changes within the dopamine system and the PFC and review recent findings regarding the effects of stress and cannabis exposure during the peripubertal period as risk factors for the emergence of schizophrenia-like deficits. Finally, we discuss peripubertal interventions appearing to circumvent the emergence of adult schizophrenia-like deficits.

The incidence of schizophrenia and schizophrenia spectrum disorders in Denmark in the period 2000-2012. A register-based study

INTRODUCTION

We aimed to examine changes over time in the incidence of broad and narrow schizophrenia spectrum disorders in Denmark from 2000 to 2012.

METHODS

Patients were classified as incident schizophrenia if registered with a first time in- or outpatient contact with relevant diagnostic codes in the Danish Psychiatric Central Register between 2000 and 2012. Their history of contacts was traced back to 1969. Broad schizophrenia included schizophrenia, schizotypal disorder, persistent delusional disorder, acute and transient psychotic disorders, schizoaffective disorders, and other nonorganic and unspecified psychotic disorders, (ICD 10 codes F20-F29). Narrow schizophrenia was defined with the ICD 10 codes F20.0-F20.9. Incidence rates (IR) and incidence rate ratios (IRR) were calculated using Poisson regression.

RESULTS

The IRR for broad schizophrenia increased by 1.43 (CI 95% 1.34-1.52) for females and 1.26 (CI 95% 1.20-1.33) for males. IRR for narrow schizophrenia increased by 1.36 (CI 95% 1.24-1.48) for females and 1.20 (CI 95% 1.11-1.29) for males. There was a significantly increased incidence in patients up to 32years of age. This was mainly explained by a significant 2-3 fold increase in outpatient incidence. We found a significant decrease in IRR for patients with broad and narrow schizophrenia aged 33 or older for both in- and outpatients.

CONCLUSION

The increased incidence of schizophrenia could partly be explained by better implementation of the diagnostic criteria for schizophrenia in child and adolescent psychiatry and improved access to early intervention services, but a true increase in incidence of schizophrenia cannot be excluded. The decrease of incidence in the older age group could indicate that the national Danish early intervention strategy was successful.

Marijuana use and use disorders in adults in the USA, 2002-14: analysis of annual cross-sectional surveys

BACKGROUND

The study of marijuana use disorders is urgently needed because of increasing marijuana legalisation in multiple jurisdictions, the effect of marijuana use on future risk of psychiatric disorders, and deleterious effects of marijuana exposure. Thus, understanding trends of marijuana use and use disorders and examining factors that might drive these trends (eg, perceptions of harms from marijuana use) is essential.

METHODS

We analysed data from US civilians aged 18 years or older who participated in annual, cross-sectional US National Surveys on Drug Use and Health from 2002 to 2014. The sample in each US state was designed to be approximately equally distributed between participants aged 12-17 years, 18-25 years, and 26 years or older. For each survey year, we estimated prevalence of marijuana use and use disorders, initiation of marijuana use, daily or near daily use, perception of great or no risk of harm from smoking marijuana, perception of state legalisation of medical marijuana use, and mean number of days of marijuana use in the previous year. Descriptive analyses, multivariable logistic regressions, and zero-truncated negative binomial regressions were applied.

FINDINGS

596 500 adults participated in the 2002-14 surveys. Marijuana use increased from 10·4% (95% CI 9·97-10·82) to 13·3% (12·84-13·70) in adults in the USA from 2002 to 2014 (β=0·0252, p<0·0001), and the prevalence of perceiving great risk of harm from smoking marijuana once or twice a week decreased from 50·4% (49·60-51·25) to 33·3% (32·64-33·96; β=-0·0625, p<0·0001). Changes in marijuana use and risk perception generally began in 2006-07. After adjusting for all covariates, changes in risk perceptions were associated with changes in prevalence of marijuana use, as seen in the lower prevalence of marijuana use each year during 2006-14 than in 2002 when perceiving risk of harm from smoking marijuana was included in models. However, marijuana use disorders in adults remained stable at about 1·5% between 2002 and 2014 (β=-0·0042, p=0·22).

INTERPRETATION

Prevalence and frequency of marijuana use increased in adults in the USA starting in approximately 2007 and showing significantly higher results in multivariable models during 2011-14 (compared with 2002). The associations between increases in marijuana use and decreases in perceiving great risk of harm from smoking marijuana suggest the need for education regarding the risk of smoking marijuana and prevention messages.

FUNDING

None.

Traditional marijuana, high-potency cannabis and synthetic cannabinoids: increasing risk for psychosis

Epidemiological evidence demonstrates that cannabis use is associated with an increased risk of psychotic outcomes, and confirms a dose-response relationship between the level of use and the risk of later psychosis. High-potency cannabis and synthetic cannabinoids carry the greatest risk. Experimental administration of tetrahydrocannabinol, the active ingredient of cannabis, induces transient psychosis in normal subjects, but this effect can be ameliorated by co-administration of cannabidiol. This latter is a constituent of traditional hashish, but is largely absent from modern high-potency forms of cannabis. Argument continues over the extent to which genetic predisposition is correlated to, or interacts with, cannabis use, and what proportion of psychosis could be prevented by minimizing heavy use. As yet, there is not convincing evidence that cannabis use increases risk of other psychiatric disorders, but there are no such doubts concerning its detrimental effect on cognitive function. All of the negative aspects are magnified if use starts in early adolescence. Irrespective of whether use of cannabis is decriminalized or legalized, the evidence that it is a component cause of psychosis is now sufficient for public health messages outlining the risk, especially of regular use of high-potency cannabis and synthetic cannabinoids.

Cannabis and development of dual diagnoses: A literature review

BACKGROUND

The use of cannabis has garnered more attention recently with ongoing efforts at marijuana legalization. The consequences of cannabis use are not clearly understood and remain a concern.

OBJECTIVES

To review the acute and persistent effects of cannabis use and associations with psychiatric disorders.

METHODS

Using Pubmed and PsychInfo, we conducted a narrative review of the literature on cannabis and psychiatric comorbidity using the keywords cannab*, marijuana, schizo*, psychosis, mood, depression, mania, bipolar, and anxiety.

RESULTS

There is substantial evidence of cannabis use leading to other illicit drug use and of an association between cannabis use and psychosis. A few reports suggest an association with bipolar disorder while the association with depression and anxiety disorders is mixed.

CONCLUSIONS

Whenever an association is observed between cannabis use and psychiatric disorders, the relationship is generally an adverse one. Age at the time of cannabis use appears to be an important factor with stronger associations observed between adolescent onset cannabis use and later onset of psychiatric disorders. Additional studies taking into account potential confounds (such as withdrawal symptoms, periods of abstinence, and other substance use) and moderators (such as age of initiation of cannabis use, the amount and frequency of drug use, prior history of childhood maltreatment, and gender) are needed to better understand the psychiatric consequences of cannabis use.

State of transition: Marijuana use among young adults in the San Francisco Bay Area

BACKGROUND

California may vote on marijuana legalization in 2016. Young adults have the highest rates of marijuana use, but little is known about the correlates of use in this age group, including factors that may be affected by policy change. We investigated whether there are differences in marijuana use by sociodemographic characteristics, psychological distress, loneliness and social support, controlling for risk factors such as alcohol and cigarette use as well as perceived harm of marijuana.

METHODS

Bivariate and multivariable analysis of past 30day marijuana use using the 2014 San Francisco Bay Area Young Adult Health Survey, a probabilistic multi-mode survey of (N=1324) young adults (aged 18-26years) residing in Alameda and San Francisco Counties, stratified by race/ethnicity.

RESULTS

291 (27%) sample participants reported current marijuana use. Compared to non-Hispanic Whites (referent) Asian/Pacific Islander respondents were less likely to use marijuana (AOR, 0.42; 95% CI, 0.22-0.80) while multiracial participants were twice as likely (AOR, 2.27; 95% CI, 1.06-4.85). Psychological distress was not related to marijuana use, but social support (AOR, 1.42; 95% CI, 1.08-1.88) and loneliness (AOR, 1.42; 95% CI, 1.09-1.86) were. Perceived harm of marijuana was inversely related to marijuana use (AOR, 0.60; 95% CI, 0.51-0.70), while smoking cigarettes (AOR, 3.95; 95% CI, 2.28-6.84) and binge drinking (AOR, 1.13; 95% CI, 1.03-1.24) were positively related.

CONCLUSIONS

Legalization policies should include public education campaigns addressing potential harms of marijuana use particularly targeting multiracial young adults who also engage in other risk behaviors, such as cigarette smoking and binge drinking.

Does screening for and intervening with multiple health compromising behaviours and mental health disorders amongst young people attending primary care improve health outcomes? A systematic review

BACKGROUND

Adolescence and young adulthood are important developmental periods. Screening for health compromising behaviours and mental health disorders during routine primary care visits has the potential to assist clinicians to identify areas of concern and provide appropriate interventions. The objective of this systematic review is to investigate whether screening and subsequent interventions for multiple health compromising behaviours and mental health disorders in primary care settings improves the health outcomes of young people.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, literature searches were conducted in Medline, PsycINFO, Scopus and Cochrane Library databases (Prospero registration number CRD42013005828) using search terms representing four thematic concepts: primary care, young people, screening, and mental health and health compromising behaviour. To be eligible for inclusion, studies had to: include a measure of health outcome; include at least 75 % of participants aged under 25 years; use a screening tool that assessed more than one health domain; and be conducted within a primary care setting. Risk of bias was assessed using the Quality Rating Scale.

RESULTS

From 5051 articles identified, nine studies fulfilled the inclusion criteria and were reviewed: two randomised controlled trials (RCTs), one pilot RCT, two clustered RCTs, one randomised study with multiple intervention groups and no control group, one cluster RCT with two active arms, one longitudinal study and one pre-post study. Seven studies, including two RCTs and one clustered RCT, found positive changes in substance use, diet, sexual health or risky sexual behaviour, alcohol-related risky behaviour, social stress, stress management, helmet use, sleep and exercise. Of only two studies reporting on harms, one reported a negative health outcome of increased alcohol use.

CONCLUSIONS

There is some evidence that the use of screening and intervention with young people for mental health disorder or health compromising behaviours in clinical settings improves health outcomes. Along with other evidence that young people value discussions of health risks with their providers, these discussions should be part of the routine primary care of young people. Further quality studies are needed to strengthen this evidence.

Cannabis use and psychological distress: An 8-year prospective population-based study among Swedish men and women

BACKGROUND

Previous studies have reported positive associations between cannabis use and mental health problems. However, it has not been possible to draw a definitive conclusion regarding the causal direction between cannabis use and impaired mental health. This study aimed at examining possible associations between cannabis use and psychological distress (as measured by the General Health Questionnaire, GHQ-12) in men and women respectively, using both measures as both exposure and outcome.

METHODS

Data were obtained from a cohort study (the Stockholm Public Health Cohort) with an 8-year follow-up in the general population in Stockholm County, Sweden. The study sample comprised 19,327 men and women, aged 18-84years, who answered surveys in 2002 and 2010.

RESULTS

Cannabis use was associated with increased odds ratios (OR) for psychological distress in women at 8-year follow-up, with OR=1.37 [1.1-1.7, 95% CI], but not in men; OR=1.14 [0.9-1.5, 95% CI]. In women, this association remained when adjusted for potential confounders (tobacco smoking, alcohol consumption, socioeconomic position (SEP) and unemployment); OR=1.27 [1.0-1.6, 95% CI]. Moreover, women reporting psychological distress at baseline had an increased risk of cannabis use at follow-up; OR=1.40 [1.1-1.8 95% CI]. However, this association was no longer statistically significant when adjustments were made for baseline cannabis use, OR=1.10 [0.8-1.5, 95% CI].

CONCLUSIONS

This study revealed that, in women, cannabis use was associated with an increased risk of psychological distress eight years later. Optimal interventions to identify these women seem warranted.

Time-varying effects of families and peers on adolescent marijuana use: Person-environment interactions across development

Studies have demonstrated that the effects of two well-known predictors of adolescent substance use, family monitoring and antisocial peers, are not static but change over the course of adolescence. Moreover, these effects may differ for different groups of youth. The current study uses time-varying effect modeling to examine the changes in the association between family monitoring and antisocial peers and marijuana use from ages 11 to 19, and to compare these associations by gender and levels of behavioral disinhibition. Data are drawn from the Raising Healthy Children study, a longitudinal panel of 1,040 youth. The strength of association between family monitoring and antisocial peers and marijuana use was mostly steady over adolescence, and was greater for girls than for boys. Differences in the strength of the association were also evident by levels of behavioral disinhibition: youth with lower levels of disinhibition were more susceptible to the influence of parents and peers. Stronger influence of family monitoring on girls and less disinhibited youth was most evident in middle adolescence, whereas the stronger effect of antisocial peers was significant during middle and late adolescence. Implications for the timing and targeting of marijuana preventive interventions are discussed.

Associations Between Cannabis Use and Physical Health Problems in Early Midlife: A Longitudinal Comparison of Persistent Cannabis vs Tobacco Users

IMPORTANCE

After major policy changes in the United States, policymakers, health care professionals, and the general public seek information about whether recreational cannabis use is associated with physical health problems later in life.

OBJECTIVE

To test associations between cannabis use over 20 years and a variety of physical health indexes at early midlife.

DESIGN, SETTING, AND PARTICIPANTS

Participants belonged to a representative birth cohort of 1037 individuals born in Dunedin, New Zealand, in 1972 and 1973 and followed to age 38 years, with 95% retention (the Dunedin Multidisciplinary Health and Development Study). We tested whether cannabis use from ages 18 to 38 years was associated with physical health at age 38, even after controlling for tobacco use, childhood health, and childhood socioeconomic status. We also tested whether cannabis use from ages 26 to 38 years was associated with within-individual health decline using the same measures of health at both ages.

EXPOSURES

We assessed frequency of cannabis use and cannabis dependence at ages 18, 21, 26, 32, and 38 years.

MAIN OUTCOMES AND MEASURES

We obtained laboratory measures of physical health (periodontal health, lung function, systemic inflammation, and metabolic health), as well as self-reported physical health, at ages 26 and 38 years.

RESULTS

The 1037 study participants were 51.6% male (n = 535). Of these, 484 had ever used tobacco daily and 675 had ever used cannabis. Cannabis use was associated with poorer periodontal health at age 38 years and within-individual decline in periodontal health from ages 26 to 38 years. For example, cannabis joint-years from ages 18 to 38 years was associated with poorer periodontal health at age 38 years, even after controlling for tobacco pack-years (β = 0.12; 95% CI, 0.05-0.18; P <.001). Additionally, cannabis joint-years from ages 26 to 38 years was associated with poorer periodontal health at age 38 years, even after accounting for periodontal health at age 26 years and tobacco pack-years (β = 0.10; 95% CI, 0.05-0.16; P <.001) However, cannabis use was unrelated to other physical health problems. Unlike cannabis use, tobacco use was associated with worse lung function, systemic inflammation, and metabolic health at age 38 years, as well as within-individual decline in health from ages 26 to 38 years.

CONCLUSIONS AND RELEVANCE

Cannabis use for up to 20 years is associated with periodontal disease but is not associated with other physical health problems in early midlife.

Motives for marijuana use among heavy-using high school students: An analysis of structure and utility of the Comprehensive Marijuana Motives Questionnaire

Motives for marijuana use are important predictors of problematic outcomes associated with marijuana use. Most measures, to date, were developed by adapting alcohol motives measures. However, the Comprehensive Marijuana Motives Questionnaire (CMMQ) was created using a bottom-up approach to evaluate twelve distinct motives for use. The CMMQ was developed and validated in a normative college population. As such, no known study has evaluated the factor structure and utility of the CMMQ in a heavy-using, high school student population. The current study utilized a sample of 252 heavy marijuana-using high school students recruited for a combination motivational enhancement/cognitive behavioral intervention. Results from baseline measures indicated that the factor structure of the CMMQ was maintained in this population. Results from multiple regression analyses revealed distinct relationships with measures of negative consequences of use, including indices of marijuana use, marijuana-related problems, self-efficacy, and internalizing and externalizing symptoms. In particular, the Coping motive was associated with several negative outcomes, which is consistent with previous marijuana and alcohol motives literature. Results suggest that the CMMQ may be useful in assessing marijuana motives among heavy marijuana-using adolescents.

Who are the adolescents saying "No" to cannabis offers

BACKGROUND AND AIMS

Adolescents who refuse direct cannabis offers and remain non-users represent a potentially very informative, yet surprisingly understudied group. We examined a range of risk and protective factors putatively associated with this poorly understood "cannabis-resilient" profile.

METHODS

Paper-and-pencil questionnaires assessing substance use, peer and family relations, and behavioral and personality characteristics were completed by 19,303 middle- and high-school students from 82 schools in Norway (response rate 84%)

RESULTS

The lifetime prevalence of cannabis use was 7.6%. Another 10.4% reported no use of the drug despite having received recent cannabis offers. Results from the multinomial logistic regression revealed a set of characteristics differentiating adolescents who resisted such offers from those who: (a) neither received the offers nor used, and, more importantly, (b) used the drug. Specifically, parent-child relationship quality, negative drug-related beliefs, absence of close relationships with cannabis-users, low delinquency, no regular tobacco use, and infrequent alcohol intoxication were all associated with increased odds of being in the cannabis-resilient vs. cannabis-user group. This pattern of results was comparable across middle- and high-school cohorts, but the parent-child relationship quality and delinquency were significantly associated with cannabis-resilient vs. cannabis-use outcome only among younger and older adolescents, respectively.

CONCLUSIONS

Among other low-risk characteristics, better relationships with parents and beliefs that drug use is problematic were associated with adolescents' refusals to accept cannabis offers. These results may have implications for novel preventive strategies targeting cannabis-exposed adolescents.

School Substance Use Norms and Racial Composition Moderate Parental and Peer Influences on Adolescent Substance Use

Parental and peer influences on adolescent substance use have been well demonstrated. However, limited research has examined how parental and peer influences vary across school contexts. This study used a multilevel approach to examine the effects of school substance use norms and school racial composition in predicting adolescent substance use (a composite measure of alcohol, tobacco, and marijuana use) and in moderating parental and peer influences on adolescent substance use. A total of 14,346 adolescents from 34 schools in a mid-western county completed surveys electronically at school. Analyses were conducted using hierarchical linear modeling. Results indicated that school-level disapproval against substance use and percentage of minority students at school were negatively associated with adolescent substance use. School-level disapproval moderated the association between peer substance use and adolescent substance use, with the association being stronger when school-level disapproval was lower. School racial composition moderated the influence of parental disapproval and peer substance use on adolescent substance use. Specifically, both the association between parental disapproval and adolescent substance use and the association between peer substance use and adolescent substance use were weaker for adolescents who attended schools with higher percentages of minority students. Findings highlighted the importance of considering the role of school contexts, in conjunction with parental and peer influences, in understanding adolescent substance use.

A critique of cannabis legalization proposals in Canada

An editorial in this issue describes a cannabis policy framework document issued by a major Canadian research centre, calling for legalization of non-medical use under strict controls to prevent increase in use, especially by adolescents and young adults who are most vulnerable to adverse effects of cannabis. It claims that such a system would eliminate the severe personal, social and monetary costs of prohibition, diminish the illicit market, and provide more humane management of cannabis use disorders. It claims that experience with regulation of alcohol and tobacco will enable a system based on public health principles to control access of youth to cannabis without the harm caused by prohibition. The present critique argues that the claims made against decriminalization and for legalization are unsupported, or even contradicted, by solid evidence. Early experience in other jurisdictions suggests that legalization increases use by adolescents and its attendant harms. Regulation of alcohol use does not provide a good model for cannabis controls because there is widespread alcohol use and harm among adolescents and young adults. Government monopolies of alcohol sale have been used primarily as sources of revenue rather than for guarding public health, and no reason has been offered to believe they would act differently with respect to cannabis. Good policy decisions require extensive unbiased information about the individual and social benefits and costs of both drug use and proposed control measures, and value judgments about the benefit/harm balance of each option. Important parts of the necessary knowledge about cannabis are not yet available, so that the value judgments are not yet possible. Therefore, a better case can be made for eliminating some of the harms of prohibition by decriminalization of cannabis possession and deferring decision about legalization until the necessary knowledge has been acquired.

A literature review and meta-analyses of cannabis use and suicidality

BACKGROUND

We lack a review of the epidemiological literature on cannabis use (acute use and chronic-usual quantity/frequency and heavy use) and suicidality (suicide death, suicide ideation, suicide attempt).

METHODS

The English language literature on Medline, PsychInfo, Google Scholar, and public-use databases was searched for original articles, critical review reports, and public use data on cannabis use and suicide for the period ranging from 1990-2015 (February). Odds ratios (OR) from random effects in meta-analyses for any cannabis use and heavy cannabis use were calculated.

RESULTS

The acute cannabis-suicidality literature mostly includes descriptive toxicology reports. In terms of death by suicide, the average positive cannabis rate was 9.50% for studies sampling from all suicides, with higher cannabis detection rates amongst suicide decedents by non-overdose methods. We found only 4 studies providing estimates for any chronic cannabis use and death by suicide (OR=2.56 (1.25-5.27)). After deleting duplicates we found 6 studies on any cannabis use and suicide ideation (OR=1.43 (1.13-1.83)), 5 studies on heavy cannabis use and suicide ideation (OR=2.53 (1.00-6.39)), 6 studies on any cannabis use and suicide attempt (OR=2.23 (1.24-4.00)) and 6 studies on heavy cannabis use and suicide attempt (OR=3.20 (1.72-5.94)).

CONCLUSIONS

We currently lack evidence that acute cannabis use increases imminent risk for suicidality. The evidence tends to support that chronic cannabis use can predict suicidality, but the lack of homogeneity in the measurement of cannabis exposure and, in some instances, the lack of systematic control for known risk factors tempered this finding.