The association between regular marijuana use and adult mental health outcomes

Persistent increased severity of cannabis use disorder symptoms in adolescents compared to adults: a one-year longitudinal study

Adolescence is a developmental period characterised by increased vulnerability to cannabis use disorder (CUD). However, previous investigations of this vulnerability have relied on cross-sectional comparisons and lack a detailed assessment of cannabis quantity, a potentially important confounding factor. Here, we aimed to investigate the one-year course of CUD in adolescents compared to adults who currently use cannabis, adjusting for a comprehensive measure of cannabis quantity. Data are from a one-year observational longitudinal study (CannTeen) of adolescents and adults who currently used cannabis regularly with five waves of assessment at 3-monthly intervals, based in London, UK. Participants were n = 70 adults (26-29, 45.7% female), who did not regularly use cannabis when they were under age 18, and n = 76 adolescents (16-17, 50.0% female). The exposure was adolescent (compared to adult) frequent cannabis use. The primary outcome was CUD symptoms measured using the cannabis use disorder identification test revised (CUDIT-R) at five time points. Models were adjusted for cannabis quantity using mean weekly standard THC units (one unit = 5 mg THC). Other covariates included gender, and whether each session occurred before or during the COVID-19 pandemic. In models adjusted for pre-registered covariates, adolescents scored 3.7 points higher on the CUDIT-R compared to the adult group across the 5 assessment waves (3.66 95% CIs 1.99, 5.34). There was also evidence of a linear reduction in symptoms over time in both groups (-0.47, 95%CIs -0.67, -0.27). Adolescents had persistently increased CUD symptoms compared to adults across the 12-month period. This association was robust after adjusting for the quantity of cannabis consumed and other covariates.

Cannabis use in adolescents and anxiety symptoms and disorders: a systematic review and meta-analysis

Background: The use of cannabis is highly prevalent during adolescence compared to the general adult population. In addition to the high comorbidity between cannabis use and anxiety disorders, early evidence suggests that cannabis may precede the development of anxiety. Moreover, adolescence represents a major developmental period for both neurobiological and psychological processes, placing these individuals at a heightened vulnerability to the influence of cannabis.Objectives: This systematic review and meta-analysis examined the prospective associations between adolescent cannabis use and subsequent anxiety outcomes (i.e. anxiety disorders and/or symptoms).Methods: Following PRISMA guidelines, a systematic review and meta-analysis were conducted encompassing data from articles published between database inception and September 2022.Results: Six longitudinal studies were identified for quantitative analysis, while twelve non-overlapping longitudinal studies were identified for qualitative review (total N = 18; 33380 subjects). Meta-analytical findings supported an association between adolescent cannabis use and the development of a subsequent anxiety disorder (Odds Ratio = 2.14, 95% CI: 1.37-3.36, p < .01). These findings were consistent with our qualitative synthesis where nine of the twelve longitudinal studies observed a significant relationship between adolescent cannabis use and exacerbation of anxiety symptoms later in life, irrespective of an anxiety disorder diagnosis.Discussion: In summary, the current evidence suggests a prospective association between adolescent cannabis use and later anxiety symptoms and disorders. These findings underscore the importance of refining research methodologies, considering sex-based differences and controlling for confounding factors, as well as implementing educational initiatives and developing clinical interventions to address the mental health risks associated with cannabis use among adolescents.

Effects of Marijuana Use in Patients Undergoing Abdominal Free Flap Breast Reconstruction

Background

Marijuana use has been associated with vascular inflammation and clotting, resulting in endothelial damage and arteritis. As marijuana use rises in the United States, few studies have evaluated its impact on surgical outcomes and wound healing in free flap breast reconstruction.

Methods

A retrospective cohort study of patients undergoing abdominal free flap breast reconstruction between 2016 and 2022 at a large metropolitan healthcare system was performed. Patient demographics, comorbidities, procedural details, and complications were analyzed. Minor complications were defined as skin or fat necrosis not requiring intervention, nipple loss, any wound requiring management in the clinic, hematoma, and seroma. Major complications were defined as reoperation, flap loss, cardiac or thromboembolic events, and hospital readmission. Active marijuana users were those with marijuana use within 12 weeks of surgery.

Results

In total, 168 patients underwent 276 deep inferior epigastric artery-based flaps for breast reconstruction. There were 21 active marijuana users. There were no significant differences in patient demographics, cancer treatment, or minor and major complications. However, there were higher rates of active nicotine use (P = 0.001) and anxiety/depression amongst active marijuana users (P = 0.002). Active users had higher rates of bilateral breast reconstruction (P = 0.029), but no significant differences in other operative details.

Conclusions

Active marijuana use of unknown frequency may be safe in patients undergoing breast free flap reconstruction. Advising marijuana abstinence preoperatively may not alter patient outcomes. Further studies of greater sample size are needed to evaluate marijuana's impact on outcomes associated with breast reconstruction using free flap.

Longitudinal patterns of polysubstance use throughout adolescence: association with adult substance use and psychosocial outcomes controlling for preadolescent risk factors in a male cohort

PURPOSE

Inconsistent reports raise the question of the extent to which poor adult outcomes are associated with adolescent polysubstance use (PSU: alcohol, marijuana, other illicit drugs) above and beyond earlier risk factors.

METHODS

Early adulthood substance-related and psychosocial outcomes were examined in association with age 13 to 17 developmental patterns of PSU in boys from urban, low SES neighborhoods (N = 926). Three classes obtained by latent growth modeling described low/non-users (N = 565, 61.0%), lower risk PSU (later onset, occasional use, 2 ≤ substances; N = 223, 24.1%), and higher risk PSU (earlier onset, frequent use, 3 ≥ substances; N = 138, 14.9%). Preadolescent individual, familial and social predictors of adolescent PSU patterns were used as covariates.

RESULTS

Adolescent PSU contributed to both age-24 substance-related outcomes (frequency of alcohol, drug use, and getting drunk, risky behaviors under influence, and use-related problems) and psychosocial outcomes (no high school diploma, professional or financial strain, ASP symptoms, criminal record) over and above preadolescent risk factors. Controlling for preadolescent risk factors, adolescent PSU made a more important contribution to adult substance use outcomes (increasing the risk by about 110%) than to psychosocial outcomes (16.8% risk increase). PSU classes showed poorer adjustment for all age-24 substance use, and for various psychosocial outcomes than low/non-users. Higher risk polysubstance users also reported poorer outcomes than their lower risk peers for most substance use outcomes, and for professional or financial strain and criminal record.

CONCLUSION

Findings highlight the contribution of adolescent PSU in a dose-response fashion, over and above preadolescent risk factors, on both homotypic and heterotypic outcomes in early adulthood.

Expectations of Patients and Their Families After the Treatment of Substance Use Disorder

BACKGROUND

Substance use disorders are economically and socially devastating to families and societies. Expectations of the patients and their families during the posttreatment phase of substance use disorder need to be emphasized to maintain a patient's sobriety and prevent relapse.

AIM

The aim of this study was to examine the prediction power of personal and sociodemographic factors of patients and their families to treatment outcomes.

METHODS

A descriptive, correlational, cross-sectional design was used. Data were collected from 80 patients treated for substance use disorders from a major psychiatric hospital and their family members regarding social, health, and psychological expectations. A three-step multiple hierarchical regression analysis was used to predict the power of personal and sociodemographic characteristics of patients' and their families' expectations to treatment outcomes.

RESULTS

Heroin use, codeine use, family education, and family support were significant predictors of rehabilitation expectation ( p < .05). Level of education and heroin use were predictors for lower levels of rehabilitation expectation, whereas family support and codeine use were indicators for higher scores of rehabilitation expectation.

CONCLUSION

Emphasis should be given to expectations of the patient and their family through appropriate psychoeducation and enhanced understanding and partnership.

Challenges and considerations for treating PTSD with medicinal cannabis: the Australian clinician's perspective

INTRODUCTION

Preclinical and experimental research have provided promising evidence that medicinal cannabis may be efficacious in the treatment of posttraumatic stress disorder (PTSD). However, implementation of medicinal cannabis into routine clinical therapies may not be straightforward.

AREAS COVERED

In this review, we describe some of the clinical, practical, and safety challenges that must be addressed for cannabis-based treatment of PTSD to be feasible in a real-world setting. These issues are especially prevalent if medicinal cannabis is to be combined with trauma-focused psychotherapy.

EXPERT OPINION

Future consideration of the clinical and practical considerations of cannabis use in PTSD therapy will be essential to both the efficacy and safety of the treatment protocols that are being developed. These issues include dose timing and titration, potential for addiction, product formulation, windows of intervention, and route of administration. In particular, exposure therapy for PTSD involves recall of intense emotions, and the interaction between cannabis use and reliving of trauma memories must be explored in terms of patient safety and impact on therapeutic outcomes.

Association between health risk behaviors and food consumption in adolescents

The study aims to evaluate the association between substance use and social isolation with food consumption in adolescents. A cross-sectional study was conducted with 2,040 adolescents from a medium-sized city in Brazil. The exposures assessed were the use of alcohol, tobacco, and other substances, and social isolation. The outcomes were the regular consumption (≥5 times/week) of beans, fruit/fruit salad, candies, and soft drinks, and an unhealthy eating score. The association between health risk behaviors and food consumption was assessed through logistic and linear regressions. Regular users of alcohol were more likely to have regular consumption of candies and soft drinks, and those who used tobacco regularly were less likely to have regular bean consumption and more likely to have regular candies consumption. The use of at least one substance was negatively associated with regular bean consumption and positively associated with regular consumption of sweets and soft drinks. Socially isolated adolescents were less likely to have regular bean consumption. Substance use was positively associated with the unhealthy eating score. In conclusion, substance use and social isolation were associated with less regular consumption of healthy food markers and greater regular consumption of unhealthy food markers.

Regular Cannabis Use During the First Year of the Pandemic: Studying Trajectories Rather Than Prevalence

INTRODUCTION

Cannabis use in the U.S. rose early in the COVID-19 pandemic, but it is unclear whether that rise was temporary or permanent. This study estimated the nature and sociodemographic correlates of U.S. adult subpopulations regularly using cannabis by examining weekly trajectories of use during the first year of the pandemic.

METHODS

Data came from the Understanding America Study, a nationally representative panel of U.S. adults (N=8,397; March 10, 2020-March 29, 2021). A growth mixture model was deployed to identify subgroups with similar regular cannabis use. Sociodemographic correlates of subgroups were examined using multinomial logistic regression.

RESULTS

Four cannabis-use groups were identified. Most participants did not regularly use cannabis (no regular use; 81.7%). The other groups increased regular use until April 2020 but then diverged. Some (7.1%) decreased thereafter, whereas others (3.4%) maintained their elevated use until October 26, 2020 before decreasing. The last group (7.7%) sustained their elevated use throughout. Individuals aged between 18 and 39 years, unmarried, living in poverty, without a college degree, and with longer unemployment or underemployment spells had higher odds of being in the other groups with more weekly use than in the no-regular-use group.

CONCLUSIONS

The analyses revealed population subgroups with prolonged regular cannabis use and a disproportionate concentration of socioeconomically vulnerable members of society in these subgroups. These findings elucidate important heterogeneity in the subpopulations using cannabis, highlighting the urgent need to tailor public health programs for subgroups that may have unique service needs.

Have recreational marijuana laws undermined public health progress on adult tobacco use?

Public health experts caution that legalization of recreational marijuana may normalize smoking and undermine the decades-long achievements of tobacco control policy. However, very little is known about the impact of recreational marijuana laws (RMLs) on adult tobacco use. Using newly available data from the Population Assessment of Tobacco and Health (PATH) and dynamic difference-in-differences and discrete-time hazard approaches, we find that RML adoption increases prior-month marijuana use among adults ages 18-and-older by 2-percentage-points, driven by an increase in marijuana initiation among prior non-users. However, this increase in adult marijuana use does not extend to tobacco use. Rather, we find that RML adoption is associated with a lagged reduction in electronic nicotine delivery systems (ENDS) use, consistent with the hypothesis that ENDS and marijuana are substitutes. Moreover, auxiliary analyses from the National Survey on Drug Use and Health (NSDUH) show that RML adoption is associated with a reduction in adult cigarette smoking. We conclude that RMLs may generate tobacco-related health benefits.

Effects of Cannabis Legalization on Adolescent Cannabis Use Across 3 Studies

INTRODUCTION

Canada, Uruguay, and 18 states in the U.S. have legalized the use of nonmedical (recreational) cannabis for adults, yet the impact of legalization on adolescent cannabis use remains unclear. This study examined whether cannabis legalization for adults predicted changes in the probability of cannabis use among adolescents aged 13-18 years.

METHODS

Data were drawn from 3 longitudinal studies of youth (spanning 1999-2020) centered in 3 U.S. states: Oregon, New York, and Washington. During this time, Oregon (2015) and Washington (2012) passed cannabis legalization; New York did not. In each study, youth average age was 15 years (total N=940; 49%-56% female, 11%-81% Black/African American and/or Latinx). Multilevel modeling (in 2021) of repeated measures tested whether legalization predicted within- or between-person change in past-year cannabis use or use frequency over time.

RESULTS

Change in legalization status across adolescence was not significantly related to within-person change in the probability or frequency of self-reported past-year cannabis use. At the between-person level, youth who spent more of their adolescence under legalization were no more or less likely to have used cannabis at age 15 years than adolescents who spent little or no time under legalization.

CONCLUSIONS

This study addresses several limitations of repeated cross-sectional studies of the impact of cannabis legalization on adolescent cannabis use. Findings are not consistent with changes in the prevalence or frequency of adolescent cannabis use after legalization. Ongoing surveillance and analyses of subpopulations are recommended.

The CannTeen Study: Cannabis use disorder, depression, anxiety, and psychotic-like symptoms in adolescent and adult cannabis users and age-matched controls

BACKGROUND

Adolescence is characterised by psychological and neural development. Cannabis harms may be accentuated during adolescence. We hypothesised that adolescents would be more vulnerable to the associations between cannabis use and mental health and addiction problems than adults.

METHOD

As part of the 'CannTeen' study, we conducted a cross-sectional analysis. There were 274 participants: split into groups of adolescent users (n = 76; 16-17 years old) and controls (n = 63), and adult users (n = 71; 26-29 years old) and controls (n = 64). Among users, cannabis use frequency ranged from 1 to 7 days/week, while controls had 0-10 lifetime exposures to cannabis. Adolescent and adult cannabis users were matched on cannabis use frequency (mean=4 days/week). We measured Diagnostic and Statistical Manual (DSM-5) Cannabis Use Disorder (CUD), Beck Depression Inventory, Beck Anxiety Inventory and Psychotomimetic States Inventory-adapted.

RESULTS

After adjustment for covariates, adolescent users were more likely to have severe CUD than adult users (odd ratio = 3.474, 95% confidence interval (CI) = 1.501-8.036). Users reported greater psychotic-like symptoms than controls (b = 6.004, 95% CI = 1.211-10.796) and adolescents reported greater psychotic-like symptoms than adults (b = 5.509, 95% CI = 1.070-9.947). User-group was not associated with depression or anxiety. No significant interactions between age-group and user-group were identified. Exploratory analyses suggested that cannabis users with severe CUD had greater depression and anxiety levels than cannabis users without severe CUD.

CONCLUSION

Adolescent cannabis users are more likely than adult cannabis users to have severe CUD. Adolescent cannabis users have greater psychotic-like symptoms than adult cannabis users and adolescent controls, through an additive effect. There was no evidence of an amplified vulnerability to cannabis-related increases in subclinical depression, anxiety or psychotic-like symptoms in adolescence. However, poorer mental health was associated with the presence of severe CUD.

Identifying risk-thresholds for the association between frequency of cannabis use and development of cannabis use disorder: A systematic review and meta-analysis

BACKGROUND

Cannabis use disorder (CUD) affects one-in-five cannabis users, presenting a major contributor to cannabis-associated disease burden. Epidemiological data identify the frequency of cannabis use as a risk factor for CUD. This review aimed to determine quantifiable risk-thresholds of the frequency of cannabis use for developing CUD.

METHODS

Systematic search of Medline, EMBASE, PsycInfo, CINAHL, and Web of Science for cohort/case-control studies that assessed the association between frequency of cannabis use and CUD from 2000 to 2022. Effect estimates were converted to risk ratios (RR). A random-effects multi-level multivariate meta-analytic approach was utilized, and sensitivity analyses conducted. Quality of included studies was assessed with the Newcastle Ottawa Scale.

RESULTS

Six prospective cohort studies were included in this review, drawn from two main source studies. Random-effect modeling showed a significant log-linear dose-response association between the frequency of cannabis use and CUD risk (p < 0.0001). The risk of CUD increased from RR:2.03 (95% CI:1.85-2.22) for 'yearly' use, to RR:4.12 (95% CI:3.44-4.95) for 'monthly" use, RR:8.37 (95% CI:6.37-11.00) for 'weekly' use, and RR:16.99 (95% CI:11.80-24.46) for 'daily' use. Multi-level modeling showed an absolute risk increase (ARI) from 3.5% (95% CI:2.6-4.7) for 'yearly' use, to 8.0% (95% CI:5.3-12.1) for 'monthly' use, to 16.8% (95% CI:8.8-32.0) for 'weekly' use, and 36% (95% CI:27.047.9) for 'daily' use.

CONCLUSION

A limited risk of CUD as a potential outcome of cannabis use exists even at infrequent levels of use, but significantly increases as frequency of use increases. Corresponding information should be conveyed to cannabis users as part of targeted prevention messaging to promote safer cannabis use.

Adult Psychiatric, Substance, and Functional Outcomes of Different Definitions of Early Cannabis Use

OBJECTIVE

Research on associations of early cannabis use with adult functioning reports mixed findings. This may be due, in part, to wide variations in the definitions of early cannabis use. This study aims to compare associations of 4 commonly used definitions of early cannabis use-related to timing, dose, duration, and associated symptoms-with adult outcomes.

METHOD

Analyses were based on a 20⁺-year longitudinal, community-representative study of 1,420 participants. Between ages 9 and 21 years (8,806 observations), participants were assessed for cannabis use and DSM-5 cannabis use disorder. In early adulthood (ages 24-26 and 30; 2,424 observations of 1,266 subjects), participants were also assessed for psychiatric, substance use, and functional outcomes.

RESULTS

All definitions of early use were associated with multiple adult outcomes in models that adjusted for sex and race/ethnicity. In models that also adjusted for childhood psychiatric problems and family adversities, only daily use and a persistent developmental subtype (defined as daily/problematic use that began in adolescence and continued into early adulthood) were associated with later substance use/disorders, poorer functional outcomes, and derailments in the transition to adulthood.

CONCLUSION

Daily, continued-over-time cannabis use beginning on adolescence was most problematic for a range of adult outcomes. Cessation of early use did not fully eliminate later risks; but was associated with fewer negative outcomes, with weaker effect sizes.

Subjective Cognitive Complaints: Predictors and Health Outcomes in People Living with HIV

There is a paucity of research on the prevalence of subjective cognitive complaints in people living with human immunodeficiency virus, along with the predictors and outcomes related to these complaints. We assessed demographics, substance use and psychiatric predictors, and HIV-related outcomes associated with subjective cognitive complaint items from the Cognitive Difficulties Scale. The sample consisted of 889 people living with HIV in the survey-based Florida Cohort. Results of multivariable regression models indicated that age (45-54), hazardous alcohol consumption, more frequent marijuana use and psychiatric symptoms (depression, anxiety, PTSD) were significant predictors of subjective cognitive complaints. Subjective cognitive complaints were associated with lower adherence to antiretroviral therapy in bivariate analyses, but this relationship was no longer significant after controlling for depression, race, alcohol and drug use. Further research into the relationship between depressive and subjective cognitive complaints may provide additional avenues for intervention.

Too Much Information? Excessive Media Use, Maladaptive Coping, and Increases in Problematic Cannabis Use during the COVID-19 Pandemic

During a health crisis like the COVID-19 pandemic, the public depends on the media for accurate and up-to-date information. However, frequent use of media for COVID-19-related information may be associated with maladaptive coping, and with increased prevalence of substance use. This study examined indirect associations between the frequency of media use for information about COVID-19 and increases in cannabis use behaviors through maladaptive coping strategies. We use data from an online survey of Israeli adult cannabis users (N = 440), conducted in May of 2020, to test associations between media use frequency for COVID-19 information and three problematic cannabis use behaviors: increased cannabis use, increased use alone, and increased use before midday. Among all respondents, 41% agreed that their cannabis use had increased since the onset of the pandemic. Analyses showed that higher frequency of media use was positively associated with all three indicators of problematic cannabis use, and that associations were partly mediated by maladaptive coping strategies. Higher frequency of media use for information about COVID-19 may be an indicator of difficulty with coping and of increased risk of escalation of cannabis use. These results have implications for assessing and mitigating the risk of coping-motivated cannabis use during a crisis.

Mental Health in Lifestyle Medicine: A Call to Action

Mental health symptoms are pervasive, with 1 in 5 American adults experiencing a mental disorder. Poor mental health is associated with a significant global cost burden, from disability to economic impacts. The field of lifestyle medicine, which emphasizes the role of lifestyle factors in the onset and treatment of disease and well-being, is well suited to address mental health. More recently, there has been attention to the need to incorporate mental health into the field of lifestyle medicine and to attend to the bidirectional role of mental health and lifestyle. Thus, there is a critical opportunity for the field of lifestyle medicine to incorporate mental health into each of the foundational pillars (diet, exercise, substance use, psychological well-being/stress, relationships, sleep) while also specifically targeting lifestyle interventions for populations with mental disorders. The current article provides a framework for the role of mental health within lifestyle medicine by addressing the scope of the problem, clarification regarding mental health, and areas of practice (ie, psychiatry), and providing an overview of the relevant mental health literature for each pillar. This article serves as a call to action to explicitly address and include mental health within all aspects of lifestyle medicine research and practice.

Associations of Cannabis Use across Adolescence and Early Adulthood With Health and Psychosocial Adjustment in Early Adulthood and Midadulthood in Men

Background:

Associations between men’s prior cannabis use and their physical and psychosocial adjustment were examined using prospective data across adolescence (ages 13-20 years), early adulthood (ages 20-30 years), and midadulthood (ages 30-38 years). The theoretical framework was based in developmental-contextual and lifespan approaches.

Method:

Models were tested using men in the Oregon Youth Study who had been studied since ages 9 to 10 years and who, in childhood, lived in neighborhoods with higher than average rates of delinquency. Cannabis use in adolescence was used to predict early adult outcomes (and early adult use to midadult outcomes). In addition, a set of covariates was added to the models, including childhood risk factors assessed at age 9 years (ie, family socioeconomic status; externalizing behaviors; and if available, the childhood proxy for the outcome [eg, age 9 intelligence scale]) and alcohol use in adolescence (or early adulthood). physical health outcomes included accidental injuries, problems resulting from a prior injury, body mass index, self-report health, and also pain and cardiovascular risk (blood pressure and pulse rate) in midadulthood. Psychosocial outcomes included income, housing insecurity, intelligence, depressive symptoms, psychosis symptoms, hostility/aggression, social problems, and attention problems.

Results:

Whereas there was almost no prediction from prior cannabis use to the physical health outcomes, there were comprehensive associations of cannabis use from the prior developmental period and psychosocial outcomes in both early adulthood and midadulthood.

Conclusion:

Cannabis use in prior developmental periods was associated with a broad range of types of poor psychosocial adjustment in adulthood.

Does substance use play a role in gender differences in residential independence and returns to the parental home?

Young adults are co-residing with their parents at higher rates now than in the past, and recent research has explored the correlates of both leaving and subsequently returning to the parental home. Of relevance here, females tend to leave home earlier than their male counterparts, and research finds that drinking and drug use are also linked to residential transitions. This research note explores if substance use during adolescence and young adulthood plays a role in gender differences in home-leaving and home-returning. We find that marijuana use plays a role in both home-leaving and home-returning, with adolescent females who use marijuana the most at risk for early exits from home, and marijuana using males the most at risk for home-returning.

Lower-Risk Cannabis Use Guidelines (LRCUG) for reducing health harms from non-medical cannabis use: A comprehensive evidence and recommendations update

BACKGROUND

Cannabis use is common, especially among young people, and is associated with risks for various health harms. Some jurisdictions have recently moved to legalization/regulation pursuing public health goals. Evidence-based 'Lower Risk Cannabis Use Guidelines' (LRCUG) and recommendations were previously developed to reduce modifiable risk factors of cannabis-related adverse health outcomes; related evidence has evolved substantially since. We aimed to review new scientific evidence and to develop comprehensively up-to-date LRCUG, including their recommendations, on this evidence basis.

METHODS

Targeted searches for literature (since 2016) on main risk factors for cannabis-related adverse health outcomes modifiable by the user-individual were conducted. Topical areas were informed by previous LRCUG content and expanded upon current evidence. Searches preferentially focused on systematic reviews, supplemented by key individual studies. The review results were evidence-graded, topically organized and narratively summarized; recommendations were developed through an iterative scientific expert consensus development process.

RESULTS

A substantial body of modifiable risk factors for cannabis use-related health harms were identified with varying evidence quality. Twelve substantive recommendation clusters and three precautionary statements were developed. In general, current evidence suggests that individuals can substantially reduce their risk for adverse health outcomes if they delay the onset of cannabis use until after adolescence, avoid the use of high-potency (THC) cannabis products and high-frequency/-intensity of use, and refrain from smoking-routes for administration. While young people are particularly vulnerable to cannabis-related harms, other sub-groups (e.g., pregnant women, drivers, older adults, those with co-morbidities) are advised to exercise particular caution with use-related risks. Legal/regulated cannabis products should be used where possible.

CONCLUSIONS

Cannabis use can result in adverse health outcomes, mostly among sub-groups with higher-risk use. Reducing the risk factors identified can help to reduce health harms from use. The LRCUG offer one targeted intervention component within a comprehensive public health approach for cannabis use. They require effective audience-tailoring and dissemination, regular updating as new evidence become available, and should be evaluated for their impact.

Variations of cannabis-related adverse mental health and addiction outcomes across adolescence and adulthood: A scoping review

INTRODUCTION

Evidence supporting associations between cannabis use and many health outcomes is growing, however it remains unclear how such associations vary across the lifespan. We therefore aim to answer the following questions: (1) Are the risks of cannabis's adverse effects on mental health and addiction-related outcomes different in adolescents than in adults? (2) What are the relationships between these cannabis's adverse effects and (a) an individual's age at first cannabis use, (b) age at assessment, and (c) duration of cannabis use?

METHODS

We searched Medline, Embase, CINAHL, and PsychINFO from inception to 18 October 2021. Two reviewers independently screened studies and descriptively synthesized results.

RESULTS

We included 140 studies. Cannabis effects on mental health and addiction-related outcomes were worse in adolescents, early cannabis initiators and cannabis users who consumed for longest periods. Evidence of worse long-term adverse effects in adolescents was substantial for psychosis, cannabis, and nicotine use disorders; mixed for depression, suicidality, other substance use and disorders; and limited for anxiety. Additionally, acute cannabis exposure had the opposite trend with adults more often reporting adverse effects than adolescents.

CONCLUSION

The available evidence suggests that cannabis use should be delayed as late as possible in adulthood and shortened in duration across the lifespan to decrease the risk of negative outcomes, while emphasizing the need for adapted harm reduction approaches. This scoping review provides evidence on the role of age and duration of exposure as determinants of cannabis-related adverse effects, which may inform prevention and harm reduction strategies.

SYSTEMATIC REVIEW REGISTRATION

https://doi.org/10.17605/OSF.IO/BYG72.

Changes in cannabis use modes among Canadian youth across recreational cannabis legalization: Data from the COMPASS prospective cohort study

INTRODUCTION

Canadian youth consume cannabis in multiple ways, including by smoking, vaping, and eating or drinking. Existing evidence suggests that these behaviours may change after law liberalization, though data regarding youth are scarce. We investigated changes in cannabis modes of use and associated factors across the federal legalization of recreational cannabis use for adults in Canada, among a large sample of underage youth before alternative products were made legally available.

METHODS

Data were available from 2953 longitudinally linked Canadian high school students who reported on their cannabis use during the 2017/2018 and 2018/2019 school years. We explored whether students maintained a single or multiple cannabis use mode(s), contracted, or expanded the number of modes used. We then used generalized estimating equations to analyse associations of baseline characteristics with use mode trajectory.

RESULTS

Expansion of cannabis use modes (42.3%) was more common than maintenance of a single mode (31.3%), maintenance of multiple modes (14.3%), or reduction (12.1%). Students who maintained multiple modes were significantly more likely to have high amounts of weekly spending money (AOR 1.68), to binge drink (AOR 2.25) or vape (AOR 1.99), to use cannabis regularly (AOR 2.67), and to endorse more symptoms of depression (AOR 1.06). School support for quitting tobacco, drug, or alcohol use appeared to have no effect.

CONCLUSIONS

Multi-modal cannabis use increased among Canadian youth in our sample. Its association with other substance use and depressive symptoms may indicate clustering of additional harms. Screening for this use pattern may assist in identifying high-risk substance use and should be considered in the design of harm reduction programming.

Associations between Recent and Cumulative Cannabis Use and Internalizing Problems in Boys from Adolescence to Young Adulthood

This study tested whether increases in recent and cumulative cannabis use were each associated with increases in internalizing problems from adolescence to young adulthood. Participants were boys from a community sample that was assessed annually from ~age 15-26 (N = 506). Boys reported on their cannabis use, depression symptoms, and anxiety/depression problems each year. Exposures were frequency of cannabis use in a given year (no use, < weekly use, weekly or more frequent use) and cumulative prior years of weekly cannabis use. Outcomes were depression symptoms and anxiety/depression problems in a given year. Analyses examined within-person associations between changes in exposures and outcomes over time, which eliminated "fixed" (unchanging) individual differences as potential confounds. Analyses also accounted for time-varying factors as potential confounds (other substance use, externalizing problems, subclinical psychotic symptoms). Results showed that increases in recent cannabis use and cumulative prior years of weekly cannabis use were each associated with increases in depression symptoms and anxiety/depression problems. After controlling for time-varying covariates, increases in cumulative prior years of weekly cannabis use, but not recent cannabis use, remained associated with increases in depression symptoms and anxiety/depression problems. Specifically, each additional year of prior weekly cannabis use was associated with a small increase in depression symptoms (b = 0.012, p = .005) and anxiety/depression problems (b = 0.009, p = .001). Associations did not vary systematically across time. There was also no evidence of reverse causation. As boys engaged in weekly cannabis use for more years, they showed increases in internalizing problems, suggesting the importance of preventing chronic weekly cannabis use.

Cannabis-Related Perceptions as Mediators of the Association Between Trait Impulsivity and Cannabis Outcomes

OBJECTIVE

Normative perceptions have been shown to mediate the effect of personality traits on cannabis outcomes. We examined descriptive norms, injunctive norms, and the role of cannabis in college life as possible mediators of the association between impulsivity-related traits (i.e., negative urgency, positive urgency, sensation seeking, perseverance, and premeditation) and cannabis outcomes (i.e., frequency of cannabis use and negative consequences) among college students from five countries.

METHOD

A total of 1,175 college students (United States, n = 698; Argentina, n = 153; Spain, n = 178; Uruguay, n = 79; and Netherlands, n = 67) who were also cannabis users (i.e., reported cannabis use at least once within the previous month) completed an online survey. We used path analysis to test whether the proposed double-mediated paths (impulsivity-like traits→perceived cannabis norms→cannabis use frequency→negative cannabis-related consequences) were invariant across countries/cultures.

RESULTS

Cannabis-related perceptions, particularly college cannabis beliefs and injunctive norms, significantly mediated the association between impulsivity and cannabis outcomes. Two significant double-mediated paths, which were invariant across sex and countries, were found: (a) higher positive urgency→higher endorsement of internalized norms→higher cannabis use frequency→more negative cannabis-related consequences and (b) higher sensation seeking→higher endorsement of injunctive norms→higher cannabis use frequency→more negative cannabis-related consequences.

CONCLUSIONS

The study corroborates previous findings on normative perceptions mediating the effects of impulsivity-like traits on cannabis outcomes and suggests that these processes may operate similarly among college student cannabis users in different legal and cultural contexts. The findings highlight the need to address internalized norms and suggest these normative perceptions may be a good intervention candidate to reduce cannabis use/consequences.

Associations of cannabis use frequency and cannabis use disorder with receiving a substance use screen and healthcare professional discussion of substance use

BACKGROUND AND OBJECTIVES

Screening, brief intervention, and referral to treatment (SBIRT) can reduce substance use, but receipt of these services by those who use cannabis frequently and have cannabis use disorder (CUD) remains unexplored. We examined cannabis use frequency and CUD's associations with the odds of receiving a substance use screening and a healthcare professional discussion among those who used healthcare services.

METHODS

Data came from the 2015-2019 National Survey on Drug Use and Health (N = 214,505 aged 18+). Among adults who used cannabis and attended healthcare settings in the past year (N = 36,374), multivariable logistic regression analysis was used to examine associations of cannabis use frequency and CUD with receiving a substance use screen and substance use discussion by a healthcare professional.

RESULTS

Cannabis use frequency was associated with higher odds of receiving a screen (adjusted odds ratio [AOR] = 1.27, 95% confidence interval [CI] = 1.14-1.41 for 300+ days of use) and a discussion among those screened (AOR = 1.83, 95% CI = 1.60-2.09 for 300+ days of use). CUD was not associated with receiving a screen, but it was positively associated with receiving a discussion among those screened (AOR = 1.22, 95% CI = 1.08-1.39). Nonmedical users were less likely to have a discussion among those screened and not screened.

DISCUSSION AND CONCLUSIONS

Findings indicate disparities in screening and discussion of substance use with patients, especially between medical and nonmedical users.

SCIENTIFIC SIGNIFICANCE

Study findings provide novel insight into differences in the reach of SBIRT services among adult cannabis users.

Oscillatory potentials abnormalities in regular cannabis users: Amacrine cells dysfunction as a marker of central dopaminergic modulation

BACKGROUND

Cannabis is a neuromodulating substance that acts on central synaptic transmission. Regular cannabis use induces a decreased capacity for dopamine synthesis in the brain. The retina is considered an easy means of investigating dysfunctions of synaptic transmission in the brain. We have previously studied the impact of regular cannabis use on retinal function. Using the N95 wave of the pattern electroretinogram, we found a 6 ms-delayed ganglion cells response. Using the b-wave of the photopic flash electroretinogram, we found a 1 ms-delayed bipolar cells response. Here, we investigated amacrine cells function because these cells are located between the bipolar cells and the ganglion cells and contribute to amplifying the signal between these two layers of the retina. We tested the effect of regular cannabis use on these retinal dopaminergic cells. We assessed the role of these cells in amplifying the delay observed previously.

METHODS

We recorded dark-adapted 3.0 flash ERG oscillatory potentials in 56 regular cannabis users and 29 healthy controls. The amplitude and implicit time of OP1, OP2, OP3 and OP4 were evaluated.

RESULTS

Cannabis users showed a significant decrease in OP2 amplitude (p = 0.029, Mann-Whitney test) and OP3 amplitude (p = 0.024, Mann-Whitney test). No significant difference was found between the groups for OP1 and OP4 amplitude or for the implicit time of oscillatory potentials.

CONCLUSIONS

These results reflect the impact of regular cannabis use on amacrine cells function. They highlight abnormalities in dopaminergic transmission and are similar to those found in Parkinson's disease. Oscillatory potentials could be used as markers of central dopaminergic modulation.

Cannabis use, use frequency, and use disorder in large metropolitan, small metropolitan, and nonmetropolitan areas

BACKGROUND

Despite significant geographical heterogeneity of sociodemographic and clinical characteristics, little is known about potential differences in cannabis use behaviors in U.S. geographic areas. In this study, we examined cannabis use behaviors in large metropolitan, small metropolitan, and nonmetropolitan areas. We focused on interactions between geographic areas and health insurance status and medical cannabis laws (MCL).

METHODS

Data came from the 2015-2018 National Survey on Drug Use and Health (NSDUH; N = 171,766 adults; N = 36,175 cannabis users). Weighted chi-squares tests of independence and multivariable Poisson regression models were used to examine study questions.

RESULTS

Past-year use was highest in large metropolitan areas (16.08 %). Frequent use was highest among nonmetropolitan area users (48.67 %). Uninsured adults had a higher likelihood of past-year use (RRR = 1.21, 95 % CI = 1.14, 1.29) and frequent use (RRR = 1.27, 95 % CI = 1.14, 1.41), but a lower likelihood of cannabis use disorder (RRR = 0.77, 95 % CI = 0.66, 0.89). Uninsured adults in nonmetropolitan areas had a higher likelihood (RRR = 1.62, 95 % CI = 1.39, 1.88) of past-year use than insured nonmetropolitan area adults. MCL state residency was associated with a higher likelihood of frequent use among nonmetropolitan (RRR = 1.39, 95 % CI = 1.11, 1.74) and small metropolitan users (RRR = 1.30, 95 % CI = 1.15, 1.47). Cannabis use disorder likelihood did not vary by geographic area.

CONCLUSIONS

Lack of health insurance and MCL state residency are significant variables affecting cannabis use behaviors in small metropolitan and/or nonmetropolitan areas.

Cannabis Use and Prospective Long-Term Association with Anxiety: A Systematic Review and Meta-Analysis of Longitudinal Studies: Usage du cannabis et association prospective à long terme avec l'anxiété: une revue systématique et une méta-analyse d'études longitudinales

OBJECTIVES

Cannabis use is proposed as a risk factor for psychosis and is associated with depressive disorders. However, the relationship between recreational cannabis use and its longitudinal implications on anxiety conditions is less studied. The aim of this investigation is to systematically evaluate published literature and perform a meta-analysis of the data.

METHODS

A systematic search was performed of MEDLINE, Embase, and PsychINFO from inception to May 31, 2020, in addition to a hand search. Longitudinal studies that evaluated the relationship of cannabis use and development of anxiety were included. Where applicable, adjusted odds ratios (ORs) were extracted, pooled, and evaluated using random-effects meta-analysis.

RESULTS

After screening of unique abstracts (n = 6835), the final evaluation included 24 studies, of which 10 reported ORs that were analyzed quantitatively. Cannabis use was significantly associated with increased odds of developing any anxiety conditions (OR = 1.25; 95% CI, 1.01 to 1.54). Cannabis use was not significantly associated with developing generalized anxiety disorder, panic disorder, or social anxiety disorder. Review of studies not reporting OR revealed mixed results but are suggestive of a link between cannabis use and increased rates/severity of anxiety.

CONCLUSIONS

Published evidence suggests that cannabis use is likely associated with increased risk of anxiety in the long term but variability of study designs precludes declaration of a causal relationship. Awareness of this association is of relevance for both clinical practice and mental health policy implementation.

Cannabis and Depression

There is a growing body of evidence pointing to the co-occurrence of cannabis use and depression. There is also some evidence that the use of cannabis may lead to the onset of depression; however, strong evidence points to the inverse association; i.e. that depression may lead to the onset or increase in cannabis use frequency. Observational and epidemiological studies have not indicated a positive long-term effect of cannabis use on the course and outcome of depression. The association between cannabis use and depression may be stronger among men during adolescence and emerging adulthood and stronger in women during midlife. There is an indication for potential genetic correlation contributing to the comorbidity of cannabis dependence and major depression, namely that serotonin (5-HT) may mediate such association and there is also evidence for specific risk alleles for cannabis addiction. There is preclinical evidence that alteration in the endocannabinoid system could potentially benefit patients suffering from depression. However, the issue of using cannabis as an anti-depressant is at an early stage of examination and there is little evidence to support it. Finally, there has been little support to the notion that selective serotonin reuptake inhibitors (SSRIs) may be effective in decreasing depressive symptoms or rates of substance use in adolescents treated for depression and a co-occurring substance use disorder. In conclusion, despite methodological limitations, research in the past decades has broadened our knowledge on the association between cannabis use and depression from epidemiological, neurological, genetic, and pharmacological perspectives.

Shifting the Paradigm on Cannabis Safety

The global movement toward legalization of cannabis is resulting in an ever-increasing public perception that cannabis is safe. Cannabis is not the first drug to be available for nonmedical use, nor is it the first to have such an unfounded safety profile. The safety of long-term exposure to phytocannabinoids is misunderstood by, and under reported to, the general public. There is evidence to suggest that long-term use of recreational cannabis may be associated with an increased risk of undesirable side effects. This evidence warrants both appropriate caution from the general public and investment in further research by government and industry sectors that are profiting from the sale of these potent psychoactive agents. There is no doubt that these compounds have medical potential. However, in addition to the medical potential, we must also remain aware of the adverse health effects that are becoming synonymous with recreational cannabis use. This perspective highlights the privileged role that cannabis has as a perceived “safe drug” in society and summarizes some concerning side effects that are becoming associated with regular nonprescribed cannabis use.

[Risk factors for risky cannabis use : A retrospective cohort study of 7671 cannabis users]

BACKGROUND

Cannabis use is widespread in Germany. So far little is known about which factors are predictive for the development of risky cannabis use.

METHODS

A retrospective cohort study was conducted. Via social networks 7671 cannabis users (mean age = 21.8 years, standard deviation (SD) = 4.5 years) were recruited (59.3% male). The end point of the online study was risky cannabis use, which was assumed with a cut-off >3 of the Severity of Dependence Scale (SDS). Predictors were gender, age, migration status, sensation seeking, a diagnosis of attention deficit hyperactivity disorder (ADHD), the age of first use and the prevalence of cannabis use in school time. In addition, characteristics of the parental home were surveyed, such as socioeconomic status, parenting style, the relationship with the parents, and mental health of the parents.

RESULTS

Risky cannabis use was reported by 29.7% of the sample. The following risk factors predicted risky cannabis use: male gender (adjusted risk ratio, ARR: 1.25), higher age (ARR: 1.01), migration status (ARR: 1.13), higher sensation seeking (ARR: 1.08), earlier onset of cannabis use (ARR: 0.94), more frequent cannabis use among peers during school time (ARR: 1.21), unstable relationship with parents (ARR: 0.97), and lower parental mental health (father: ARR: 0.98; mother: ARR: 0.96). No associations could be found for a diagnosis of ADHD, parental socioeconomic status and parenting style.

CONCLUSION

Potentially influenceable risk factors for risky cannabis use are relationship quality in the parental home and early onset of cannabis use.

Rapid increase in the prevalence of cannabis use among people with depression in the United States, 2005-17: the role of differentially changing risk perceptions

AIMS

To estimate trends in the prevalence of cannabis use and risk perceptions of cannabis use from 2005 to 2017 among United States people with and without depression.

DESIGN

Linear time trends of the prevalence of any, daily and non-daily past 30-day cannabis use and perceived great risk associated with regular cannabis use (outcome variables) among people with and without past-year depression were assessed using logistic regression with survey year as the predictor. All analyses were adjusted for gender, age, race/ethnicity and income; models assessing time trends of cannabis use prevalence were also adjusted for perceived risk.

SETTING

The United States: National Survey on Drug Use and Health, an annual cross-sectional survey, 2005-17 public use data files.

PARTICIPANTS

A total of 728 691 people aged ≥ 12 years.

MEASUREMENTS

Self-report of any, daily and non-daily past 30-day cannabis use and perceived great risk associated with regular cannabis use.

FINDINGS

The prevalence of any, daily and non-daily cannabis use in the past month was higher among those with depression versus those without [e.g. 2017 for any use: 18.94 versus 8.67%; adjusted odds ratio (aOR) = 2.17 (95% confidence interval (CI) = 1.92, 2.45)]. Any, daily and non-daily cannabis use increased among people with and without depression from 2005 to 2017, yet the increase in any (aORs = 1.06 versus 1.05; P = 0.008) and daily (aORs = 1.10 versus 1.07; P = 0.021) cannabis use adjusted for socio-demographic characteristics was more rapid among those with depression. Perception of great risk associated with regular cannabis use was significantly lower among those with depression (P < 0.001) and decreased significantly more rapidly over the study period among people with depression, compared with those without (aORs = 0.89 versus 0.92; P < 0.001).

CONCLUSIONS

The prevalence of cannabis use in the United States increased from 2005 to 2017 among people with and without depression and was approximately twice as common among those with depression. People with depression experienced a more rapid decrease in perception of risk, which may be related to the more rapid increase in any and daily past-month cannabis use in this group.

Trends in college students' alcohol, nicotine, prescription opioid and other drug use after recreational marijuana legalization: 2008-2018

BACKGROUND

Young adult college students may be particularly sensitive to recreational marijuana legalization (RML). Although evidence indicates the prevalence of marijuana use among college students increased after states instituted RML, there have been few national studies investigating changes in college students' other substance use post-RML.

METHOD

The cross-sectional National College Health Assessment-II survey was administered twice yearly from 2008 to 2018 at four-year colleges and universities. Participants were 18-26 year old undergraduates attending college in states that did (n = 243,160) or did not (n = 624,342) implement RML by 2018. Outcome variables were self-reported nicotine use, binge drinking, illicit drug use, and misuse of prescription stimulants, sedatives, and opioids. Other variables included individual and contextual covariates, and institution-reported institutional and community covariates. Publicly available information was used to code state RML status at each survey administration.

RESULTS

Accounting for state differences and time trends, RML was associated with decreased binge drinking prevalence among college students age 21 and older [OR (95% CI) = 0.91 (0.87 - 0.95), p < .0001] and increased sedative misuse among minors [OR (95% CI) = 1.20 (1.09 - 1.32), p = .0003]. RML did not disrupt secular trends in other substance use.

CONCLUSIONS

In the context of related research showing national increases in college students' marijuana use prevalence and relative increases following state RML, we observed decreases in binge drinking and increases in sedative use that both depended on age. Findings support some specificity in RML-related changes in substance use trends and the importance of individual factors.

Modifiable risk and protective factors for anxiety disorders among adults: A systematic review

Anxiety disorders are highly prevalent in the general population and associated with high rates of impairment and disability. This burden highlights the need to identify risk factors that individuals can modify without professional intervention. A systematic review was conducted to identify studies that examined modifiable risk and protective factors for anxiety disorders among adults in the general population. Searches were conducted in PubMed, PsycINFO and MEDLINE using medical subject headings and text words related to risk factors, protective factors, and each anxiety disorder. Screening, data extraction, and quality assessment were performed by three study authors. Modifiable risk and protective factors from 19 studies across seven countries were identified. Risk factors identified included cigarette smoking, alcohol use, cannabis use, negative appraisals of life events, avoidance, and occupational factors. Protective factors included social support, coping, and physical activity. Cigarette smoking was the most studied risk factor. Support was found for cigarette smoking as a risk factor for agoraphobia and panic disorder. Mixed results were found for generalized anxiety disorder and specific phobia. Across disorders, smoking frequency was associated with greater risk. Results indicate an important gap in the literature in that few studies have examined modifiable risk factors for anxiety disorders.

Cannabis and Cannabinoids in Mood and Anxiety Disorders: Impact on Illness Onset and Course, and Assessment of Therapeutic Potential

BACKGROUND AND OBJECTIVES

Cannabis use is common in people with and mood and anxiety disorders (ADs), and rates of problematic use are higher than in the general population. Given recent policy changes in favor of cannabis legalization, it is important to understand how cannabis and cannabinoids may impact people with these disorders. We aimed to assess the effects of cannabis on the onset and course of depression, bipolar disorder, ADs, and post-traumatic stress disorder (PTSD), and also to explore the therapeutic potential of cannabis and cannabinoids for these disorders.

METHODS

A systematic review of the literature was completed. The PubMed® database from January 1990 to May 2018 was searched. We included longitudinal cohort studies, and also all studies using cannabis or a cannabinoid as an active intervention, regardless of the study design.

RESULTS

Forty-seven studies were included: 32 reported on illness onset, nine on illness course, and six on cannabinoid therapeutics. Cohort studies varied significantly in design and quality. The literature suggests that cannabis use is linked to the onset and poorer clinical course in bipolar disorder and PTSD, but this finding is not as clear in depression and anxiety disorders (ADs). There have been few high-quality studies of cannabinoid pharmaceuticals in clinical settings.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

These conclusions are limited by a lack of well-controlled longitudinal studies. We suggest that future research be directed toward high-quality, prospective studies of cannabis in clinical populations with mood and ADs, in addition to controlled studies of cannabinoid constituents and pharmaceuticals in these populations. (Am J Addict 2019;00:00-00).

Cannabis Use and the Risk for Psychosis and Affective Disorders

Objective: This review discusses the relationship between cannabis use and psychotic, bipolar, depressive, and anxiety disorders, as well as suicide. It summarizes epidemiological evidence from cross-sectional and long-term prospective studies and considers possible etiological mechanisms. Methods: Systematic reviews and methodologically robust studies in the field (from inception to February 2019) were identified using a comprehensive search of Medline, PsychINFO, and Embase and summarized using a narrative synthesis. Results: Consistent evidence, both from observational and experimental studies, has confirmed the important role of cannabis use in the initiation and persistence of psychotic disorders. The size of the effect is related to the extent of cannabis use, with greater risk for early cannabis use and use of high-potency varieties and synthetic cannabinoids. Accumulating evidence suggests that frequent cannabis use also increases the risk for mania as well as for suicide. However, the effect on depression is less clear and findings on anxiety are contradictory with only a few methodologically robust studies. Furthermore, the relationship with common mental disorders may involve reverse causality, as depression and anxiety are reported to lead to greater cannabis consumption in some studies. Pathogenetic mechanisms focus on the effect of tetrahydrocannabinol (THC, the main psychoactive ingredient of cannabis) interacting with genetic predisposition and perhaps other environmental risk factors. Cannabidiol (CBD), the other important ingredient of traditional cannabis, ameliorates the psychotogenic effects of THC but is absent from the high-potency varieties that are increasingly available. Conclusions: The evidence that heavy use of high-THC/low-CBD types of cannabis increases the risk of psychosis is sufficiently strong to merit public health education. Evidence of similar but smaller effects in mania and suicide is growing, but is not convincing for depression and anxiety. There is much current interest in the possibility that CBD may be therapeutically useful.

Cessation of cannabis use: A retrospective cohort study

Given recent findings of a worldwide increase in cannabis use, a better understanding of the factors associated with cannabis use is needed. Most previous studies have focused on factors that predict the initiation of cannabis use, but less is known about factors associated with cessation. The present study is a retrospective cohort study of 6467 current or former cannabis users aged 15 to 46 years (mean age 22.5, SD = 4.8). Data were collected via an online survey advertised in social media. All analyzed participants had used cannabis for at least three years. Approximately 16.3% (n = 1055) of the sample population had not used cannabis in the previous 12 months and were classified as quitters; all others (83.7%, n = 5412) reported at least monthly use. Cessation was predicted by older current age, being female, nonmigrant status, less sensation seeking, using psychological treatment, more peer cannabis use during youth and more negative first experience with cannabis. An additional predictor was a nonincrease in the frequency of cannabis use in the first three years of use, indicating that trajectories of cannabis use are set early on and might be used to identify risk groups for early preventive measures.

Orbitofrontal cortex volume prospectively predicts cannabis and other substance use onset in adolescents

BACKGROUND

Identifying neural characteristics that predict cannabis initiation is important for prevention efforts. The orbitofrontal cortex is critical for reward response and may be vulnerable to substance-induced alterations.

AIMS

We measured orbitofrontal cortex thickness, surface area, and volume prior to the onset of use to predict cannabis involvement during an average nine-year follow-up.

METHODS

Adolescents (n=118) aged 12-15 years completed baseline behavioral assessment and magnetic resonance imaging scans, then were followed up to 13 years with annual substance use interviews. Logistic regression examined baseline (pre-substance use) bilateral medial and lateral orbitofrontal cortex characteristics (volume, surface area, or cortex thickness) as predictors of regular cannabis use by follow-up. Post-hoc multinomial logistic regression assessed whether orbitofrontal cortex characteristics significantly predicted either alcohol use alone or cannabis+alcohol co-use. Brain-behavior relationships were assessed through follow-up correlations of baseline relationships between orbitofrontal cortex and executive functioning, reward responsiveness, and behavioral approach traits.

RESULTS

Larger left lateral orbitofrontal cortex volume predicted classification as cannabis user by follow-up (p=0.025, odds ratio=1.808). Lateral orbitofrontal cortex volume also predicted cannabis+alcohol co-user status (p=0.008, odds ratio=2.588), but not alcohol only status. Larger lateral orbitofrontal cortex volume positively correlated with greater baseline reward responsiveness (p=0.030, r=0.348). There were no significant results by surface area or cortex thickness (ps>0.05).

CONCLUSIONS

Larger left lateral orbitofrontal cortex measured from ages 12-15 years and prior to initiation of substance use was related to greater reward responsiveness at baseline and predicted classification as a cannabis user and cannabis+alcohol co-user by final follow-up. Larger lateral orbitofrontal cortex volume may represent aberrant orbitofrontal cortex maturation and increasing vulnerability for later substance use.

The Effects of Marijuana Use on Transitions through Stages of Alcohol Involvement for Men and Women in the NESARC I and II

Background: With the changing context of marijuana use, it is critical to identify effects of use. We extend previous work by examining whether marijuana use influences progression and remission through alcohol involvement stages for men and women. Methods: Data come from Waves I and II of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC, n = 34,432). We assess the potential influence of marijuana use at Wave 1 on transitions across three latent statuses of alcohol involvement between waves. We apply propensity score weighting to account for shared risk factors. Results: Marijuana use was associated cross-sectionally and longitudinally with alcohol involvement statuses for both sexes. After propensity score adjustment, men with marijuana histories were 3.50 times as likely as men without such histories to transition from no to severe problems across waves relative to staying in the same status (p < .001). Women with marijuana histories were 1.74 times as likely as women without such histories to transition from no problems at Wave 1 to moderate problems at Wave 2 (p = .030) and 0.13 times as likely as women without such histories to transition from severe problems to no problems (p = .006). Conclusions: Results suggest that marijuana use impacts progression to more serious stages of alcohol involvement for both men and women, as well as hinders remission among women. Findings point to the importance of screening those with marijuana histories for alcohol problems, as well as the need to understand the mechanism of why marijuana use may increase the risk of alcohol problems.

Serious psychological distress and daily cannabis use, 2008 to 2016: Potential implications for mental health?

BACKGROUND

Daily cannabis use is increasing in the United States (US). Yet, it is not known whether daily cannabis use is disproportionately common, or whether it has increased differentially over time, by mental health status. This study estimated the prevalence of daily cannabis use among adults in the US with and without past-month serious psychological distress (SPD; measured by the Kessler Psychological Distress Scale (K6)) in 2016 and estimated trends in daily cannabis use by past-30-day SPD status from 2008 to 2016.

METHODS

Data were drawn from adults age 18 and older in the 2008-2016 National Survey on Drug Use and Health (combined total analytic sample n = 356,413). Linear time trends of daily cannabis use, stratified by SPD status, were assessed using logistic regression models with continuous year as the predictor.

RESULTS

In 2016, past-month daily cannabis use was significantly more common among those with past-month SPD (8.07%), compared to those without past-month SPD (2.66%). Daily cannabis use increased significantly from 2008 to 2016 among those both with and without SPD although use among those with SPD was persistently higher than use among those without SPD over the time period studied.

CONCLUSIONS

Daily cannabis use is significantly more common among persons with serious psychological distress and is increasing in this group, as well as among those without. Given this increase and the high prevalence of cannabis use among those with SPD, it may be important to consider potential consequences of this increased use for those with mental health vulnerabilities.

Parenting Practices in the Context of Legal Marijuana: Voices from Seattle Parents

OBJECTIVES

This study examined marijuana-related parenting attitudes, behaviors, and challenges in the context of nonmedical marijuana legalization in Washington State.

METHOD

Qualitative data were collected via 6 focus groups with a total of 54 parents of preteen and teenage children, following the opening of the first marijuana retail store in Seattle in 2014. A structured interview protocol was used to ask parents about their marijuana-related parenting behaviors and about information, skills, or strategies that parents might find helpful while raising children in a state where nonmedical marijuana use is legal for adults. Transcripts were analyzed using thematic content analysis with NVivo software.

RESULTS

Findings indicate that most parents talked to their children about marijuana, communicating rules and information about the effects of the drug. Although most parents felt that marijuana use by underage youth was not acceptable, many recognized that it was something teens would likely experiment with. Most parents set guidelines about marijuana in their households, but several faced challenges monitoring their children's behavior (e.g., use of edibles), imposing consequences when children used marijuana, reconciling societal and personal norms, and deciding whether or not to disclose their own use. Parents expressed that they would benefit from learning strategies to deal with these challenges, including factual information and parenting skills, through programs offered in schools or community settings.

CONCLUSIONS

Results have implications for future research that seeks to inform prevention program development and shape policies attuned to the needs of parents.

Cannabis and mental illness: a review

With the increasing push to legalize cannabis in Western nations, there is a need to gage the potential impact of this policy change on vulnerable populations, such as those with mental illness, including schizophrenia, mood, and anxiety disorders. This is particularly important as there are strong motives in these individuals to seek short-term reward (e.g., "getting high"). Nonetheless, data to support the beneficial effects of cannabis use in psychiatric populations are limited, and potential harms in patients with psychotic and mood disorders have been increasingly documented. This article reviews the effects of cannabis in people with mental illness. Then, we provide a reconciliation of the addiction vulnerability and allostatic hypotheses to explain co-morbidity addiction in mentally ill cannabis users, as well as to further aid in developing a rational framework for the assessment and treatment of problematic cannabis use in these patients.

Cannabis use during alcohol treatment is associated with alcohol-related problems one-year post-treatment

BACKGROUND

Prior research shows that cannabis use during treatment for Alcohol Use Disorders (AUD) is related to fewer abstinent days from alcohol, although only among those who use cannabis 1-2x/month. Here we extend prior research by assessing the relationship between the frequency of cannabis use during AUD treatment and post-treatment alcohol-related consequences.

METHODS

Data come from the Combined Pharmacotherapies and Behavioral Interventions (COMBINE) Study, a large US randomized control trial of treatments for AUD. The current analyses include 206 cannabis users and 999 cannabis abstainers and compare longitudinal drinking data between those who used cannabis versus those who abstained during COMBINE treatment. The primary exposure was quartiles of cannabis use (Q1: less than 1x/month during treatment, Q2: 1-2x/month, Q3: 4-8x/month, Q4: 12x/month or more), with cannabis abstainers as the reference group. Outcomes were alcohol-related problems at the end of treatment and one-year post-treatment as measured by the Drinker Inventory Consequences.

RESULTS

Compared to cannabis abstinence, the most frequent use during treatment was related to 1.44 times as many physical consequences one-year post-treatment. Cannabis use was not related to physical consequences immediately after treatment, or to intrapersonal, interpersonal, social responsibility or impulse control problems at either post-treatment time point.

CONCLUSIONS

In a sample of individuals in treatment for AUD, using cannabis 12x/month or more during treatment is associated with increased rates of physical consequences attributed to alcohol use. Individuals in treatment for AUD who also use cannabis might benefit from reducing or stopping cannabis use to avoid alcohol-related physical problems.

Orbitofrontal connectivity is associated with depression and anxiety in marijuana-using adolescents

BACKGROUND

Prevalence of marijuana (MJ) use among adolescents has been on the rise. MJ use has been reported to impact several brain regions, including frontal regions such as the orbitofrontal cortex (OFC). The OFC is involved in emotion regulation and processing and has been associated with symptoms of depression and anxiety. Therefore, we hypothesized that adolescent MJ users would show disruptions in OFC connectivity compared with healthy adolescents (HC) which would be associated with symptoms of mood and anxiety.

METHODS

43 MJ-using and 31 HC adolescents completed clinical measures including the Hamilton Anxiety Scale (HAM-A) and Hamilton Depression Rating Scale (HAM-D). Resting-state functional magnetic resonance imaging data was also acquired for all participants.

RESULTS

In MJ users, increased depressive symptoms were associated with increased connectivity between the left OFC and left parietal regions. In contrast, lower ratings of anxiety were associated with increased connectivity between right and left OFC and right occipital and temporal regions. These findings indicate significant differences in OFC connectivity in MJ-using adolescents, which correlated with mood/anxiety.

LIMITATIONS

Future studies with an increased number of female participants is required to address potential sex differences in connectivity patterns related to symptoms of depression and anxiety.

CONCLUSIONS

This study highlights the association between OFC connectivity, MJ use, and symptoms of depression and anxiety in adolescents. These findings provide further insight into understanding the neural correlates that modulate the relationship between comorbid MJ use and mood disorders and could potentially help us better develop preventive and treatment measures.

Medical cannabis legalization and state-level prevalence of serious mental illness in the National Survey on Drug Use and Health (NSDUH) 2008-2015

Although research has established a link between cannabis legalization and use, and cannabis use and mental health, the relationship between medical cannabis legalization and mental health remains uncharacterized. This analysis investigated the relationship between state medical cannabis laws (restrictive, i.e. covering a narrow set of medical conditions; or liberal, i.e. covering a broad range of medical conditions), whether the law permits patients to petition their physician to approve medical cannabis use for specific medical conditions, and state prevalence of serious mental illness (SMI) in the National Survey of Drug Use and Health 2008-2015. In a covariate-adjusted meta-regression, liberal laws were significantly associated with higher prevalence of SMI (Coeff = 0.003, SE = 0.001, p < .001). Restrictive laws (Coeff = 0.001, SE = 0.001, p = .285) and the ability to petition physician approval (Coeff = -0.001, SE = 0.001, p = .140) were non-significant. When added to the model, state past-year cannabis use was significantly associated with higher prevalence of SMI (Coeff = 0.037, SE = 0.015, p = .018), liberal laws remained significant (Coeff = 0.002, SE = 0.001, p = .015), and restrictive laws (Coeff = -0.0001, SE = 0.001, p = .945) and the ability to petition a physician (Coeff = 0.001, SE = 0.001, p = .290) remained non-significant. Medical cannabis laws are likely related to state mental health, and a higher prevalence of cannabis use partially explains this relationship.