Does cannabis use predict the first incidence of mood and anxiety disorders in the adult population?

Longitudinal patterns of alcohol and cannabis use among US young adults: Correlates and implications for problematic health outcomes

INTRODUCTION

Alcohol and cannabis use are common during young adulthood. Less is known regarding correlates of alcohol-cannabis use patterns and related problematic health outcomes.

METHODS

Using longitudinal survey data (Fall 2018, 2019, 2020) from 2,194 young adults (YAs; ages 18-34), bivariate analyses and multivariable logistic regressions examined: (1) Wave 1 (W1) sociodemographics and psychosocial factors (i.e., adverse childhood experiences [ACEs], depressive symptoms, personality traits, parent and peer alcohol and cannabis use) in relation to W3 past-month use group (i.e., use of neither, alcohol only, cannabis only, both/co-use); and (2) W3 use group in relation to W5 problematic alcohol use (Alcohol Use Disorder Identification Test), problematic cannabis use (Cannabis Use Disorder Identification Test), and depressive/anxiety symptoms (Patient Health Questionnaire - 4 item).

RESULTS

Overall, 42.3% reported W3 alcohol-only use, 34.9% co-use, 17.8% no use, and 5.0% cannabis-only use. Those reporting W3 co-use reported greater W1 extraversion, openness, friend alcohol/cannabis use, and were more likely to report parent cannabis use (vs. no use); reported less conscientiousness, greater friend cannabis use, and were more likely to report depressive symptoms and parent cannabis use (vs. alcohol-only use); and reported greater friend alcohol use, and were more likely to report parent alcohol use (vs. cannabis-only use). W3 co-use was associated with higher odds of W5 problematic alcohol use (vs. alcohol-only use) and problematic cannabis use (vs. cannabis-only use).

CONCLUSIONS

Substance use messaging and interventions should consider YAs' alcohol-cannabis co-use and the unique correlates of such use.

Recent trends in hospital admission due to bipolar disorder in 10-19-year-olds in Spain: A nationwide population-based study

INTRODUCTION

Bipolar disorder (BD) hospitalization rates in children and adolescents vary greatly across place and over time. There are no population-based studies on youth BD hospitalizations in Spain.

METHODS

We identified all patients aged 10-19 hospitalized due to BD in Spain between 2000 and 2021, examined their demographic and clinical characteristics, and assessed temporal trends in hospitalizations - overall and stratified by age and presence of additional psychiatric comorbidity. We used Joinpoint regressions to identify inflection points and quantify whole-period and annual percentage changes (APCs) in trends.

RESULTS

Of 4770 BD hospitalizations in 10-19-year-olds between 2000 and 2021 (average annual rate: 4.8 per 100,000), over half indicated an additional psychiatric comorbidity, most frequently substance abuse (62.2%), mostly due to cannabis (72.4%). During the study period, admissions increased twofold with an inflection point: Rates increased annually only between 2000 and 2008, for APCs 34.0% (95% confidence interval: 20.0%, 71.1%) among 10-14-year-olds, 10.3% (6.4%, 14.3%) among 15-19-year-olds, and 15.5% (11.5%, 22.7%) among patients with additional psychiatric comorbidity. Between 2009 and 2021, rates decreased moderately among 10-14-year-olds - APC: -8.3% (-14.1%, -4.4%) and slightly among 15-19-year-olds without additional psychiatric comorbidity - APC: -2.6(-5.7, -1.0), remaining largely stable among 15-19-year-olds overall.

CONCLUSIONS

Recent trends in hospitalization due to BD in 10-19-year-olds in Spain indicate salient increases in the early 2000s - especially among (i) patients aged 10-14 (decreasing moderately after 2009 among 10-14-year-olds and plateauing among 15-19-year-olds) and (ii) patients with additional psychiatric comorbidity (i.e., cannabis use disorder). These findings suggest links with recent changes in clinical practices for children and recent trends in substance use among Spanish youth.

Cannabis use and mood disorders: a systematic review

Background

Problematic cannabis use is highly prevalent among people with mood disorders. This underscores the need to understand the effects of cannabis and cannabinoids in this population, especially considering legalization of recreational cannabis use.

Objectives

We aimed to (1) systematically evaluate cross-sectional and longitudinal studies investigating the interplay between cannabis use, cannabis use disorder (CUD), and the occurrence of mood disorders and symptoms, with a focus on major depressive disorder (MDD) and bipolar disorder (BD) and; (2) examine the effects of cannabis on the prognosis and treatment outcomes of MDD and BD.

Methods

Following PRISMA guidelines, we conducted an extensive search for English-language studies investigating the potential impact of cannabis on the development and prognosis of mood disorders published from inception through November 2023, using EMBASE, PsycINFO, PubMed, and MEDLINE databases.

Results

Our literature search identified 3,262 studies, with 78 meeting inclusion criteria. We found that cannabis use is associated with increased depressive and manic symptoms in the general population in addition to an elevated likelihood of developing MDD and BD. Furthermore, we observed that cannabis use is linked to an unfavorable prognosis in both MDD or BD.

Discussion

Our findings suggest that cannabis use may negatively influence the development, course, and prognosis of MDD and BD. Future well-designed studies, considering type, amount, and frequency of cannabis use while addressing confounding factors, are imperative for a comprehensive understanding of this relationship.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023481634.

Youth cannabis use and subsequent health service use for mood and anxiety disorders: A population-based cohort study

Epidemiologic research suggests a modest association between youth cannabis use and mood and anxiety disorders (MADs). However, current evidence is based mostly on cohort studies using data from the 20th century when cannabis was significantly less potent than today. We linked population-based survey data from 2009 to 2012 with administrative records of health services covered under universal healthcare up to 2017. The cohort included youth aged 12 to 24 years at baseline living in Ontario, Canada with no prior MAD health service use (n = 8,252). We conducted a multivariable Cox model to estimate the association between cannabis use frequency (never, Collapse

Key Words

• Anxiety disorders
• Cannabis
• Mood disorders
• Psychiatry
• Youth

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MESH Headings

• Humans
• Adolescent
• Anxiety Disorders/epidemiology
• Anxiety Disorders/therapy
• Cannabis
• Cohort Studies
• Ontario/epidemiology
• Hospitalization
• Patient Acceptance of Health Care

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Affiliation(s)

André J McDonald Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Peter Boris Centre for Addictions Research, St. Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada; Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada; Michael G. DeGroote Centre for Medicinal Cannabis Research, McMaster University, Hamilton, Ontario, Canada.
Paul Kurdyak Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada; ICES, Toronto, Ontario, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
Jürgen Rehm Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Clinical Psychology and Psychotherapy, Technische Universität Dresden, Dresden, Germany; Department of Psychiatry and Psychotherapy, Centre for Interdisciplinary Addiction Research (ZIS), University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russian Federation
Michael Roerecke Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
Susan J Bondy Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada

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Cannabis and Anxiety: A Critical Review

Introduction

Cannabis has been reported to have both anxiogenic and anxiolytic effects. Habitual cannabis use has been associated with anxiety disorders (AD). The causal pathways and mechanisms underlying the association between cannabis use (CU)/cannabis use disorder (CUD) and anxiety remain unclear. We examined the literature via a systematic review to investigate the link between cannabis and anxiety. The hypotheses studied include causality, the common factor theory, and the self-medication hypothesis.

Methods

Critical systematic review of published literature examining the relationship of CU/CUD to AD or state-anxiety, including case reports, literature reviews, observational studies, and preclinical and clinical studies. A systematic MEDline search was conducted of terms including: [anxiety], [anxiogenic], [anxiolytic], [PTSD], [OCD], [GAD], [cannabis], [marijuana], [tetrahydrocannabinol], [THC].

Results

While several case-control and cohort studies have reported no correlation between CU/CUD and AD or state anxiety (N = 5), other cross-sectional, and longitudinal studies report significant relationships (N = 20). Meta-analysis supports anxiety correlating with CU (N = 15 studies, OR = 1.24, 95% CI: 1.06-1.45, p = 0.006) or CUD (N = 13 studies, OR = 1.68, 95% CI: 1.23-2.31, p = 0.001). PATH analysis identifies the self-medication hypothesis (N = 8) as the model that best explains the association between CU/CUD and AD or state-anxiety. Despite the support of multiple large cohort studies, causal interpretations (N = 17) are less plausible, while the common factor theory (N = 5), stress-misattribution hypothesis, and reciprocal feedback theory lack substantial evidential support.

Conclusion

The association between cannabis and anxiety is best explained by anxiety predisposing individuals toward CU as a method of self-medication. A causal relationship in which CU causes AD incidence is less likely despite multiple longitudinal studies suggesting so.

Association between Cannabis Use Disorder and Mental Health Disorders in the Adolescent Population: A Cohort Study

INTRODUCTION

According to the literature, early initiation to cannabis use and a dependent pattern of use are important risk factors for the development of mental health disorders. However, there are few cohort studies which look at the development of mental health disorders associated with cannabis use among young people with cannabis use disorder (CUD). The aim of the study was to determine the cumulative incidence of mental health disorders and the risk of developing mental health disorders among minors who commenced treatment for CUD in Catalonia during 2015-2019.

METHODS

This was a retrospective fixed cohort study, matched for confounding variables, based on data from the Catalan Health Surveillance System. The exposed cohort comprised young people who entered treatment for CUD during 2015-2019 (n = 948) and who were minors on the date of commencing treatment. Matching was done with a paired cohort (n = 4,737), according to confounding variables. Individuals with a diagnosis of a mental health disorder prior to the study period were excluded. The cumulative incidence was calculated for mental health disorders for the exposed and the paired cohorts and stratified by type of mental disorder. Incidence rate ratios were estimated using the conditional Poisson model with robust variance, stratified by sex.

RESULTS

The cumulative incidence for development of a mental health disorder was 19.6% in the exposed cohort and 3.1% in the paired cohort; with higher incidence among females (females 32.7%; males 15.8%). The exposed cohort had an 8.7 times increased risk of developing a mental health disorder than the paired cohort. The most frequent diagnoses were reaction to severe stress, adjustment disorder, and personality disorders.

CONCLUSION

This study confirmed that the exposed cohort was at increased risk of developing mental health disorders compared to the paired cohort. To date, few studies have analyzed the association between cannabis use and the development of mental health disorders, considering cannabis dependence. Further studies should be undertaken considering CUD. In addition, more studies are needed to understand the factors that determine the development of CUD. Further research in these areas would contribute to the design of prevention strategies aimed at those young individuals with a higher risk of developing cannabis dependence and suffering its consequences.

Cannabis use and its relationship with bipolar disorder: A systematic review and meta-analysis

Cannabis use has been stated as a causal risk factor for the occurrence of schizophrenia and other psychotic disorders. There is a dearth of literature stating the association of cannabis with bipolar disorder. This review aimed to find the repercussion of cannabis use on the onset of the first episode of bipolar disorder and the worsening of the symptoms in pre-existing illness. A thorough systematic review of the existing literature was carried out using the PRISMA guidelines. PubMed, Medline, EMBASE, SCOPUS, and Google-scholar databases were searched for studies fitting our study's inclusion and exclusion criteria. A total of 25 studies were included in the systematic review and out of these 25 studies, five prospective studies met the inclusion criteria for the primary outcome meta-analysis. A total sample of 13,624 individuals was included in these five studies. A fixed effect model was used in the meta-analysis of these five studies and it revealed an association between cannabis and bipolar disorder with an effect size of 2.63 (95% CI: 1.95-3.53) (heterogeneity: chi² = 3.01, df = 3 (P = 0.39); I² = 0%). Our findings propose that cannabis use may precipitate or worsen bipolar disorder. This highlights the importance of the detrimental effect of cannabis use on bipolar disorder and the need to discourage cannabis use in the youth culture. High-quality prospective studies are required to delineate the effect of cannabis use on bipolar disorder.

Transition From Substance-Induced Psychosis to Schizophrenia Spectrum Disorder or Bipolar Disorder

Objective: The authors investigated transitions to schizophrenia spectrum or bipolar disorder following different types of substance-induced psychosis and the impact of gender, age, number of emergency admissions related to substance-induced psychosis, and type of substance-induced psychosis on such transitions. Methods: All patients in the Norwegian Patient Registry with a diagnosis of substance-induced psychosis from 2010 to 2015 were included (N=3,187). The Kaplan-Meier method was used to estimate cumulative transition rates from substance-induced psychosis to either schizophrenia spectrum disorder or bipolar disorder. Cox proportional hazard regression was used to estimate hazard ratios for transitions to schizophrenia spectrum or bipolar disorders associated with gender, age, number of emergency admissions, and type of substance-induced psychosis. Results: The 6-year cumulative transition rate from substance-induced psychosis to schizophrenia spectrum disorder was 27.6% (95% CI=25.6–29.7). For men, the risk of transition was higher among younger individuals and those with either cannabis-induced psychosis or psychosis induced by multiple substances; for both genders, the risk of transition was higher among those with repeated emergency admissions related to substance-induced psychosis. The cumulative transition rate from substance-induced psychosis to bipolar disorder was 4.5% (95% CI=3.6–5.5), and the risk of this transition was higher for women than for men. Conclusions: Transition rates from substance-induced psychosis to schizophrenia spectrum disorder were six times higher than transition rates to bipolar disorder. Gender, age, number of emergency admissions, and type of substance-induced psychosis affected the risk of transition.

Canadian Network for Mood and Anxiety Treatments (CANMAT) Task Force Report: A Systematic Review and Recommendations of Cannabis use in Bipolar Disorder and Major Depressive Disorder

BACKGROUND

Given the increasing acceptability and legalization of cannabis in some jurisdictions, clinicians need to improve their understanding of the effect of cannabis use on mood disorders.

OBJECTIVE

The purpose of this task force report is to examine the association between cannabis use and incidence, presentation, course and treatment of bipolar disorder and major depressive disorder, and the treatment of comorbid cannabis use disorder.

METHODS

We conducted a systematic literature review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, searching PubMed, Embase, PsycINFO, CINAHL and Cochrane Central Register of Controlled Trials from inception to October 2020 focusing on cannabis use and bipolar disorder or major depressive disorder, and treatment of comorbid cannabis use disorder. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach was used to evaluate the quality of evidence and clinical considerations were integrated to generate Canadian Network for Mood and Anxiety Treatments recommendations.

RESULTS

Of 12,691 publications, 56 met the criteria: 23 on bipolar disorder, 21 on major depressive disorder, 11 on both diagnoses and 1 on treatment of comorbid cannabis use disorder and major depressive disorder. Of 2,479,640 participants, 12,502 were comparison participants, 73,891 had bipolar disorder and 408,223 major depressive disorder without cannabis use. Of those with cannabis use, 2,761 had bipolar disorder and 5,044 major depressive disorder. The lifetime prevalence of cannabis use was 52%-71% and 6%-50% in bipolar disorder and major depressive disorder, respectively. Cannabis use was associated with worsening course and symptoms of both mood disorders, with more consistent associations in bipolar disorder than major depressive disorder: increased severity of depressive, manic and psychotic symptoms in bipolar disorder and depressive symptoms in major depressive disorder. Cannabis use was associated with increased suicidality and decreased functioning in both bipolar disorder and major depressive disorder. Treatment of comorbid cannabis use disorder and major depressive disorder did not show significant results.

CONCLUSION

The data indicate that cannabis use is associated with worsened course and functioning of bipolar disorder and major depressive disorder. Future studies should include more accurate determinations of type, amount and frequency of cannabis use and select comparison groups which allow to control for underlying common factors.

Cannabis use and related clinical variables in patients with obsessive-compulsive disorder

OBJECTIVE

Limited studies have investigated cannabis use in patients with obsessive-compulsive disorder (OCD), despite its widespread use by patients with psychiatric illnesses. The aim of this study was to assess the frequency, correlates, and clinical impact of cannabis use in an Italian sample of patients with OCD.

METHODS

Seventy consecutive outpatients with OCD were recruited from a tertiary specialized clinic. To assess cannabis-related variables, patients completed a questionnaire developed for the purpose of this study, investigating cannabis use-related habits and the influence of cannabis use on OCD symptoms and treatments. A set of clinician and self-reported questionnaires was administered to measure disease severity. The sample was then divided into three subgroups according to the pattern of cannabis use: "current users" (CUs), "past-users" (PUs), and "non-users" (NUs).

RESULTS

Approximately 42.8% of patients reported lifetime cannabis use and 14.3% reported current use. Approximately 10% of cannabis users reported an improvement in OCD symptoms secondary to cannabis use, while 23.3% reported an exacerbation of anxiety symptoms. CUs showed specific unfavorable clinical variables compared to PUs and NUs: a significant higher rate of lifetime use of tobacco, alcohol, and other substances, and a higher rate of pre-OCD onset comorbidities. Conversely, the three subgroups showed a similar severity of illness.

CONCLUSION

A considerable subgroup of patients with OCD showed a predisposition towards cannabis use and was associated with some specific clinical characteristics, suggesting the need for targeted consideration and interventions in this population.

Is early exposure to cannabis associated with bipolar disorder? Results from a Finnish birth cohort study

BACKGROUND AND AIMS

There are few longitudinal studies assessing the association of cannabis use and subsequent onset of bipolar disorder. We aimed to measure the association between early cannabis exposure and subsequent bipolar disorder.

DESIGN, SETTING AND PARTICIPANTS

Observational study linking a sample from the northern Finland birth cohort 1986 (n = 6325) to nation-wide register data to examine the association of life-time cannabis exposure at age 15/16 years and subsequent bipolar disorder until age 33 (until the end of 2018); 6325 individuals (48.8% males) were included in the analysis.

MEASUREMENTS

Cannabis exposure was measured via self-report. Bipolar disorder was measured via bipolar disorder-related diagnostic codes (ICD-10: F30.xx, F31.xx) collected from the Care Register for Health Care 2001-18, the Register of Primary Health Care Visits 2011-18, the medication reimbursement register of the Social Insurance Institution of Finland 2001-05 and the disability pensions of the Finnish Center for Pensions 2001-16. Potential confounders included demographic characteristics, parental psychiatric disorders, emotional and behavioral problems and other substance use.

FINDINGS

Three hundred and fifty-two adolescents (5.6%) reported any cannabis use until the age of 15-16 years. Of the whole sample, 66 (1.0%) were diagnosed with bipolar disorder. Adolescent cannabis use was associated with bipolar disorder [hazard ratio (HR) = 3.46; 95% confidence interval (CI) = 1.81-6.61]. This association remained statistically significant after adjusting for sex, family structure and parental psychiatric disorders (HR = 3.00; 95% CI = 1.47-6.13) and after further adjusting for adolescent emotional and behavioral problems (HR = 2.34; 95% CI = 1.11-4.94). Further adjustments for frequent alcohol intoxications, daily smoking and lifetime illicit drug use attenuated the associations to statistically non-significant.

CONCLUSIONS

In Finland, the positive association between early cannabis exposure and subsequent development of bipolar disorder appears to be confounded by other substance use.

Anxiety sensitivity and cannabis use motives among trauma-exposed young adult cannabis users

BACKGROUND AND OBJECTIVES

Anxiety sensitivity, or fear of anxious arousal, may be an important risk factor for problematic cannabis use. Specifically, anxiety sensitivity may motivate cannabis use to cope with distress, particularly among trauma-exposed individuals. The current study tested associations among anxiety sensitivity, its subdomains, and cannabis use motives in a sample of trauma-exposed cannabis users. We hypothesized elevated anxiety sensitivity, particularly cognitive concerns, would be associated with increased maladaptive coping use motives, after covarying for the number of traumas and cannabis use quantity.

METHOD

Hypotheses were tested in a cross-sectional study of trauma-exposed young adult cannabis users (N = 56) (Mage  = 20.7 years, 59% women, 73% white). Participants completed self-report measures, and a clinical interview assessing cannabis use quantity.

RESULTS

Multiple regression analyses indicated that elevated anxiety sensitivity was associated with increased cannabis use coping motives, after covarying for the number of traumas experienced and cannabis use quantity. Specifically, higher levels of anxiety sensitivity cognitive and social concerns were associated with coping motives for cannabis use.

DISCUSSION AND CONCLUSIONS

Anxiety sensitivity, particularly concerns about cognitive dyscontrol and negative social evaluations of anxious arousal, may motivate cannabis use to cope with stress among trauma-exposed cannabis users. Future research should include prospective studies with diverse samples to replicate results and determine whether intervening on anxiety sensitivity could reduce maladaptive coping motives for cannabis use.

SCIENTIFIC SIGNIFICANCE

The current study replicates prior research indicating anxiety sensitivity, particularly cognitive concerns, is associated with maladaptive cannabis use. Expanding on prior research, findings indicated anxiety sensitivity is associated with coping motives for cannabis use among trauma-exposed cannabis users.

Associations between cannabis use, cannabis use disorder, and mood disorders: longitudinal, genetic, and neurocognitive evidence

RATIONALE

Cannabis use among people with mood disorders increased in recent years. While comorbidity between cannabis use, cannabis use disorder (CUD), and mood disorders is high, the underlying mechanisms remain unclear.

OBJECTIVES

We aimed to evaluate (1) the epidemiological evidence for an association between cannabis use, CUD, and mood disorders; (2) prospective longitudinal, genetic, and neurocognitive evidence of underlying mechanisms; and (3) prognosis and treatment options for individuals with CUD and mood disorders.

METHODS

Narrative review of existing literature is identified through PubMed searches, reviews, and meta-analyses. Evidence was reviewed separately for depression, bipolar disorder, and suicide.

RESULTS

Current evidence is limited and mixed but suggestive of a bidirectional relationship between cannabis use, CUD, and the onset of depression. The evidence more consistently points to cannabis use preceding onset of bipolar disorder. Shared neurocognitive mechanisms and underlying genetic and environmental risk factors appear to explain part of the association. However, cannabis use itself may also influence the development of mood disorders, while others may initiate cannabis use to self-medicate symptoms. Comorbid cannabis use and CUD are associated with worse prognosis for depression and bipolar disorder including increased suicidal behaviors. Evidence for targeted treatments is limited.

CONCLUSIONS

The current evidence base is limited by the lack of well-controlled prospective longitudinal studies and clinical studies including comorbid individuals. Future studies in humans examining the causal pathways and potential mechanisms of the association between cannabis use, CUD, and mood disorder comorbidity are crucial for optimizing harm reduction and treatment strategies.

Frustrative nonreward and cannabinoid receptors: Chronic (but not acute) WIN 55,212-2 treatment increased resistance to change in two reward downshift tasks

Assessing the role of cannabinoid (CB) receptors in behavior is relevant given the trend toward the legalization of medicinal and recreational marijuana. The present research aims at bridging a gap in our understanding of CB-receptor function in animal models of frustrative nonreward. These experiments were designed to (1) determine the effects of chronic administration of the nonselective CB1-receptor agonist WIN 55,212-2 (WIN) on reward downshift in rats and (2) determine whether the effects of chronic WIN were reducible to acute effects. In Experiment 1, chronic WIN (7 daily injections, 10 mg/kg, ip) accelerated the recovery of consummatory behavior after a 32-to-4% sucrose downshift relative to vehicle controls. In addition, chronic WIN eliminated the preference for an unshifted lever when the other lever was subject to a 12-to-2 pellet downshift in free-choice trials, but only in animals with previous experience with a sucrose downshift. In Experiment 2, acute WIN (1 mg/kg, ip) reduced consummatory behavior, but did not affect recovery from a 32-to-4% sucrose downshift. The antagonist SR 141716A (3 mg/kg, ip) also failed to interfere with recovery after the sucrose downshift. In Experiment 3, acute WIN administration (1 mg/kg, ip) did not affect free-choice behavior after a pellet downshift, although it reduced lever pressing and increased magazine entries relative to vehicle controls. The effects of chronic WIN on frustrative nonreward were not reducible to acute effects of the drug. Chronic WIN treatment in rats, like chronic marijuana use in humans, seems to increase resistance to the effects of frustrative nonreward.

Bipolar Disorder and Polysubstance Use Disorder: Sociodemographic and Clinical Correlates

INTRODUCTION

Patients with bipolar disorder (BD) often show comorbidity with substance use disorder (SUD) with a negative impact on clinical course, prognosis, and functioning. The role of polysubstance use disorder (polySUD) is understudied. The aim of the present paper is to evaluate the sociodemographic and clinical characteristics associated with BD and comorbid SUD, focusing on polySUD, in order to phenotype this specific group of patients and implement adequate treatment and prevention strategies.

METHODS

A cross-sectional study was conducted involving 556 patients with a primary diagnosis of BD (376 without SUD, 101 with SUD, and 79 with polySUD). A semi-structured interview was administered to collect sociodemographic variables, clinical characteristics, and pharmacological treatment. ANOVA and chi-square tests were used to compare the three groups. Significantly different variables were then inserted in multivariate logistic regression.

RESULTS

Patients affected by BD and polySUD were younger, and more frequently males and single, than patients with SUD or without SUD. Indeed, the prevalence of patients affected by BD and polySUD living in residential facilities was higher than in the other groups. Moreover, earlier age at onset, higher prevalence of psychotic and residual symptoms, involuntary hospitalization, and a family history of psychiatric disorders were associated with polySUD in patients suffering from BD. Lastly, patients with BD and polySUD were more likely to take four or more medications, particularly benzodiazepines and other drugs. At the multinomial regression, younger age, male gender, early age at onset, psychotic and residual symptoms, positive family history of psychiatric disorders, and use of benzodiazepines remained significantly associated with polySUD in patients with BD.

CONCLUSION

Our findings show a specific profile of patients with BD and polySUD. It is important to conduct research on this topic in order to adopt specific therapeutic strategies, minimize the use of polypharmacy, and aim at full remission and mood stabilization.

Substance use as a risk factor for bipolar disorder: A systematic review

Detecting substance use as a predictor of bipolar disorder (BD) is important for clinicians to perform accurate and early diagnosis, as well as better manage the treatment of individuals with BD. The aim of this systematic review was to describe whether substance use is a predictor of BD. A literature search was conducted using the following databases: PubMed, PsycINFO, and Embase. All eligible studies published up to February 9, 2021 were included. This systematic review included 22 studies. We found that 66.7% of the studies assessing overall substance use found that overall substance use was a risk factor for BD. Regarding the specific substances assessed, cannabis use was described as a risk factor for BD in 55.6% of the studies, nonmedical use of prescription medications was a risk factor for BD in 50% of the studies, nicotine was found as a risk factor for BD in 50% of the studies, and alcohol use was described as a risk factor for BD in 42.9% of the studies assessing it. Only one study assessed whether cocaine use was a risk factor for BD and found a significant association. Interestingly, some studies suggested that the greater frequency of cannabis use was associated with greater risk to develop BD or hypomanic/manic symptoms. In conclusion, there is evidence supporting that substance use is a risk factor for BD. Importantly, when assessing the risk factors for BD related to psychoactive substance use, special attention should be given for the frequency of cannabis use.

Bipolar Disorder and Comorbid Use of Illicit Substances

Substance use disorders (SUD) are highly prevalent in bipolar disorder (BD) and significantly affect clinical outcomes. Incidence and management of illicit drug use differ from alcohol use disorders, nicotine use of behavioral addictions. It is not yet clear why people with bipolar disorder are at higher risk of addictive disorders, but recent data suggest common neurobiological and genetic underpinnings and epigenetic alterations. In the absence of specific diagnostic instruments, the clinical interview is conducive for the diagnosis. Treating SUD in bipolar disorder requires a comprehensive and multidisciplinary approach. Most treatment trials focus on single drugs, such as cannabis alone or in combination with alcohol, cocaine, or amphetamines. Synopsis of data provides limited evidence that lithium and valproate are effective for the treatment of mood symptoms in cannabis users and may reduce substance use. Furthermore, the neuroprotective agent citicoline may reduce cocaine consumption in BD subjects. However, many of the available studies had an open-label design and were of modest to small sample size. The very few available psychotherapeutic trials indicate no significant differences in outcomes between BD with or without SUD. Although SUD is one of the most important comorbidities in BD with a significant influence on clinical outcome, there is still a lack both of basic research and clinical trials, allowing for evidence-based and specific best practices.

Navigating the diagnostic challenges of bipolar disorder in youth

ABSTRACT

Bipolar disorder in youth is difficult to diagnose and treat, but early detection is important to mitigate risks and improve patient outcomes. This article evaluates the unique challenges of diagnosing and treating bipolar disorder in children and adolescents. Bipolar disorder is associated with a significant personal and societal health burden and frequently is misdiagnosed and incorrectly treated. More research is needed to understand the pathophysiology of bipolar disorder and which treatment options are best throughout the lifespan.

Who would try (or use more) cannabis if it were legal?

INTRODUCTION

This study sought to determine: (i) whether decriminalisation of cannabis use would increase the proportion who would try the drug; and (ii) the proportion who would use more cannabis; and (iii) explore their characteristics.

METHODS

Australian National Drug Strategy Household surveys were used to address (i)-(iii). Significant independent predictors of (i) and (ii) were identified using logistic regression.

RESULTS

An estimated 4.2% of the population aged 14 and over (n = 882 708) who have never tried cannabis before would try it, if use of the drug were made legal, while 2.6% of the population aged 14 and over (537 000) would use more cannabis if its use were made legal. Respondents were more likely to say they would try cannabis if they were male, younger or suffered from a mild, moderate and/or severe level of psychological stress. Respondents were more likely to say they would use more cannabis if they were male, younger, psychologically stressed and not currently frequent users of the drug.

DISCUSSION AND CONCLUSIONS

Decriminalisation of cannabis use is likely to result in an increase in consumption of the drug among young people with mental health problems. If cannabis use is decriminalised, Australian State and Territory Governments should make provision for a possible increase in demand for drug treatment and for public education on the risks associated with frequent/prolonged cannabis use.

Environmental Risk Factors in Bipolar Disorder and Psychotic Depression: A Systematic Review and Meta-Analysis of Prospective Studies

OBJECTIVE

The aim of this systematic review and meta-analysis was to study the association between specific environmental risk factors (ERF) and later development of Bipolar disorder and Psychotic depression.

METHODS

A systematic search of prospective studies was conducted in MEDLINE, EMBASE and PsycINFO databases, and supplemented by hand searching, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (registration number: CRD42018092253). Selected ERF included: pre-/peri-natal factors-paternal age at birth, maternal infection, obstetric complications, perinatal stress; early childhood factors-urbanicity at birth, childhood infection, childhood adversity; later life factors-substance misuse, ethnic minority and migration, urbanicity later in life, stressful life events, and traumatic head injury. Pooled effect sizes of the association between these ERF and affective psychoses were calculated from systematically selected studies. When studies examining each ERF were insufficient for meta-analysis, results were presented narratively.

RESULTS

Forty-six studies were included for quantitative analyses among selected ERF for affective psychosis, with significant association found for paternal age >40 years (OR 1.17, 95%CI 1.12-1.23), early (OR 1.52, 95%CI 1.07-2.17) and late (OR 1.32, 95%CI 1.05-1.67) gestational age, childhood adversity (OR 1.33, 95%CI 1.18-1.50), substance misuse (OR 2.87, 95%CI 1.63-5.50), and being from an ethnic minority (OR 1.99, 95%CI 1.39-2.84).

CONCLUSIONS

These results suggest some shared environmental load between non-affective and affective psychosis, implying generalized risks for psychosis rather than for specific diagnostic categories. Nonetheless, published studies for some ERF in the affective psychoses are scarce, and further longitudinal studies are needed.

Assessing Aerobic Fitness Level in Relation to Affective and Behavioral Functioning in Emerging Adult Cannabis Users

BACKGROUND

Cannabis use is common amongst emerging adults and increasingly linked to negative mood and neurocognitive performance. Aerobic fitness, however, may be positively linked. Therefore we assess the potential moderating influence of aerobic fitness on affective and behavioral functioning associated with cannabis.

METHODS

After 3-weeks of abstinence, 83 16-26 year-olds (38 cannabis, 45 controls) completed self-report inventories (BDI-II, STAI-state, FrSBe, BIS/BAS), an objective emotion functioning measure (PennCNP), and VO2 max testing. Multiple regressions assessed symptoms from past year cannabis use, VO2 max, and cannabis*VO2, controlling for alcohol, cotinine, gender, and BMI.

RESULTS

Past year cannabis use was associated with increased depressive symptoms (p=.04), BIS/BAS component (p=.002), and emotion recognition (p=.045).

CONCLUSIONS

Results suggest a robust association between past year cannabis use and depressive symptoms and behavioral and affective functioning. Aerobic fitness, however, did not moderate these relationships. Efforts should be made to inform the public of concerns regarding the potential negative impact of cannabis on mood.

Comorbid Cannabis Use Disorder with Major Depression and Generalized Anxiety Disorder: A Systematic Review with Meta-analysis of Nationally Representative Epidemiological Surveys

BACKGROUND

Studies have shown a high degree of comorbidity between cannabis use disorder (CUD) and other mental illnesses. However, there is a paucity of research on the comorbidity between CUD with major depression (MD) and generalized anxiety disorder (GAD). This systematic review with meta-analysis aimed to assess the prevalence and strength of association between co-morbid CUD with MD and GAD.

METHODS

An extensive search of Medline, CINAHL, PsycINFO, EMBASE, and grey literature were conducted to cover articles published between January 1^st, 1980, and July 31^st, 2020. Inclusion criteria were publications in English Language, original research, nationally representative samples, and non-clinical randomly selected adult populations. A systematic review and meta-analysis for the prevalence and ORs for comorbid CUD with MD or GAD were done.

RESULTS

A total of 67 articles were identified by the electronic searches. A full-text review yielded 8 publications on nationally representative epidemiological surveys. 12-month and lifetime comorbidity estimates were extracted and used for the meta-analysis. CUD was strongly associated with MDE (OR 3.22; 2.31 - 4.49) and with GAD (OR 2.99; 2.14 - 4.16).

LIMITATIONS

Limitations of this study include the heterogeneity observed due to the combination of studies from different geographic regions with different modifications of diagnostic criteria and varied response rates. This was addressed with a random-effects model.

CONCLUSION

This review confirms the evidence of high prevalence and a 3-fold comorbid association between CUD with MD and CUD with GAD. Implementation of evidence-based policy interventions with effective, integrated management of comorbid CUDs with psychiatric disorders may contribute to positive patient outcomes.

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.

Emotion regulation in emerging adults with major depressive disorder and frequent cannabis use

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Linear mixed modelling was used to analyze fMRI data on an emotion task.

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Cannabis use and major depressive disorder interacted with emotion regulation.

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The biggest effects were observed in the left temporal lobe.

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Emotion regulation strategy and depressive symptoms also predicted activity.

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The combination of MDD and cannabis was more complex than strictly additive.

In people with mental health issues, approximately 20% have co-occurring substance use, often involving cannabis. Although emotion regulation can be affected both by major depressive disorder (MDD) and by cannabis use, the relationship among all three factors is unknown. In this study, we used fMRI to evaluate the effect that cannabis use and MDD have on brain activation during an emotion regulation task. Differences were assessed in 74 emerging adults aged 16–23 with and without MDD who either used or did not use cannabis. Severity of depressive symptoms, emotion regulation style, and age of cannabis use onset were also measured. Both MDD and cannabis use interacted with the emotion regulation task in the left temporal lobe, however the location of the interaction differed for each factor. Specifically, MDD showed an interaction with emotion regulation in the middle temporal gyrus, whereas cannabis use showed an interaction in the superior temporal gyrus. Emotion regulation style predicted activity in the right superior frontal gyrus, however, this did not interact with MDD or cannabis use. Severity of depressive symptoms interacted with the emotion regulation task in the left middle temporal gyrus. The results highlight the influence of cannabis use and MDD on emotion regulation processing, suggesting that both may have a broader impact on the brain than previously thought.

Clinical Investigation on the Impact of Cannabis Abuse on Thyroid Hormones and Associated Psychiatric Manifestations in the Male Population

Cannabis abuse is a common public health issue and may lead to considerable adverse effects. Along with other effects, the dependence on cannabis consumption is a serious problem which has significant consequences on biochemical and clinical symptoms. This study intends to evaluate the harmful effects of the use of cannabis on thyroid hormonal levels, cardiovascular indicators, and psychotic symptoms in the included patients. This prospective multicenter study was conducted on cannabis-dependent patients with psychotic symptoms (n = 40) vs. healthy control subjects (n = 40). All participants were evaluated for psychiatric, biochemical, and cardiovascular physiological effects. Patients were selected through Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria and urine samples, exclusively for the evaluation of cannabis presence. Serum thyroid stimulating hormone (TSH), T3, and T4 levels were measured using the immunoassay technique. Patients were assessed for severity of depressive, schizophrenic, and manic symptoms using international ranking scales. Various quantifiable factors were also measured for the development of tolerance by cannabis. Among the patients of cannabis abuse, 47.5% were found with schizophrenia, 20% with schizoaffective symptoms, 10% with manic symptoms, and 22.5% with both manic and psychotic symptoms. In the group-group and within-group statistical analysis, the results of thyroid hormones and cardiovascular parameters were non-significant. The psychiatric assessment has shown highly significant (p < 0.001) difference of positive, negative, general psychopathology, and total scores [through Positive and Negative Syndrome Scale (PANSS) rating scales] in patients vs. the healthy control subjects. The study revealed that cannabis abuse did not significantly alter thyroid hormones and cardiovascular parameters due to the development of tolerance. However, the cannabis abuse might have a significant contributing role in the positive, negative, and manic symptoms in different psychiatric disorders.

The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review

Background: Cannabis is known to have a broad range of effects on behavior, including experiencing a "high" and tranquility/relaxation. However, there are several adverse behavioral sequalae that can arise from cannabis use, depending on frequency of use, potency (e.g., THC content), age of onset, and cumulative exposure. This systematic review examined evidence for cannabis-related adverse behavioral sequalae in otherwise healthy human subjects. Methods: Following PRISMA guidelines, we conducted a systematic review of cross-sectional and longitudinal studies from 1990 to 2020 that identified cannabis-related adverse behavioral outcomes in subjects without psychiatric and medical co-morbidities from PubMed and PsychInfo searches. Key search terms included "cannabis" OR "tetrahydrocannabinol" OR "cannabidiol" OR "marijuana" AND "anxiety" OR "depression" OR "psychosis" OR "schizophrenia" "OR "IQ" OR "memory" OR "attention" OR "impulsivity" OR "cognition" OR "education" OR "occupation". Results: Our search detected a total of 2,870 studies, from which we extracted 124 relevant studies from the literature on cannabis effects in the non-clinical population. Effects of cannabis on several behavioral sequelae including cognition, motivation, impulsivity, mood, anxiety, psychosis intelligence, and psychosocial functioning were identified. The preponderance of the evidence suggests that frequency of cannabis use, THC (but not CBD) content, age of onset, and cumulative cannabis exposure can all contribute to these adverse outcomes in individuals without a pre-existing medical condition or psychiatric disorder. The strongest evidence for the negative effects of cannabis are for psychosis and psychosocial functioning. Conclusions: Although more research is needed to determine risk factors for development of adverse behavioral sequelae of cannabis use, these findings underline the importance of understanding vulnerability to the adverse effects of cannabis, which has implications for prevention and treatment of problematic cannabis use.

Hit the chronic… physical activity: are cannabis associated mental health changes in adolescents attenuated by remaining active?

PURPOSE

High-frequency cannabis use in adolescents has been associated with adult mental illness. In contrast, physical activity has been demonstrated to benefit mental health status. The purpose of this study was to examine whether, within a 1-year prospective study design, changes in cannabis use frequency are associated with changes in mental health, and whether meeting physical activity guidelines moderates these associations.

METHODS

COMPASS (2012-2021) is a hierarchical longitudinal health data survey from a rolling cohort of secondary school students across Canada; student-level mental health data linked from Years 5 (2016/17) and 6 (2017/18) were analysed (n = 3173, 12 schools). Multilevel conditional change regression models were used to assess associations between mental health scores change, cannabis use change and physical activity guideline adherence change after adjusting for covariates.

RESULTS

Adopting at least weekly cannabis use was associated with increases in depressive and anxiety symptoms and decreases in psychosocial well-being. Maintaining physical activity guidelines across both years improved psychosocial well-being regardless of cannabis use frequency, and offset increases in depressive symptoms among individuals who adopted high frequency cannabis use. Physical activity adherence had no apparent relationship with anxiety symptoms.

CONCLUSION

Regardless of the sequence of events, adopting high frequency cannabis use may be a useful behavioural marker of current or future emotional distress, and the need for interventions to address mental health. Physical activity adherence may be one approach to minimizing potential changes in mental health associated with increasing cannabis use.

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.

Parsing impulsivity in individuals with anxiety and depression who use Cannabis

BACKGROUND

Individuals with anxiety/depression may impulsively use cannabis to acutely induce positive affect and attenuate aversive mood states. However, few studies have attempted to parse impulsivity displayed by anxious/depressed cannabis users. This investigation examined what aspects of impulsivity characterize those individuals using self-report and functional MRI (fMRI) measures.

METHODS

Individuals with any lifetime anxiety/depression diagnoses and problematic cannabis use ("Anx/Dep+CB"; n=42) were compared to a propensity score-matched group with very low cannabis use ("Anx/Dep-lowCB"; n=42), and a healthy control group (n=37). Impulsivity was measured using the UPPS-P Impulsivity Questionnaire and the Stop Signal Task (SST) during fMRI. For UPPS-P, regression models estimated group-by-impulsivity subscale interactions with post-hoc pairwise tests. For the SST, similar regression models were estimated with four a-priori regions of interest (ROIs; right opercularis, orbitalis, dorsal and ventral anterior insula) during stop-success and stop-failure processing. Null SST findings were followed up using Bayes factor analysis to quantify the evidence in support of the null hypothesis.

RESULTS

For the UPPS-P, a significant group-by-subscale interaction indicated that the Anx/Dep+CB group exhibited higher levels of impulsivity on the negative- and positive-urgency subscales relative to both comparison groups. Higher negative-urgency correlated with heavier lifetime cannabis use across groups. For the SST, there were no ROI task activation differences. Bayes factor analysis determined the null findings were at least three times more likely than the alternative hypothesis for all ROIs.

CONCLUSIONS

Impulsivity under periods of heightened affect, but not motor response inhibitions, characterized anxious/depressed individuals who use cannabis.

Marijuana use and major depressive disorder are additively associated with reduced verbal learning and altered cortical thickness

Marijuana (MJ) use and major depressive disorder (MDD) have both been associated with deficits in verbal learning and memory as well as structural brain abnormalities. It is not known if MJ use by those with MDD confers additional impairment. The goal of this study was to examine unique and combined effects of MDD and MJ use on verbal memory and brain structure. Young adults (n=141) aged 18-25 years with MJ use and no lifetime MDD (MJ, n=46), MDD and no MJ use (MDD, n=23), MJ use and lifetime MDD (MDD+MJ, n=24), and healthy controls without MDD or MJ use (CON, n=48) were enrolled. Participants completed the California Verbal Learning Test, Second Edition (CVLT-II), a measure of verbal learning and memory. A sub-sample of 82 participants also underwent a structural magnetic resonance imaging (MRI) scan. Group differences in CVLT-II performance, cortical thickness, and hippocampal volume were assessed. We found an additive effect of MDD and MJ on memory recall. Only MDD, but not MJ, was associated with poorer initial learning, fewer words recalled, more intrusion errors, and lower percent retention. There was also an additive effect of MDD and MJ use on reduced cortical thickness in the middle temporal gyrus. Findings indicate that MJ use and MDD have additive adverse associations with verbal recall and cortical thickness in the middle temporal gyrus, suggesting that MJ use among those with MDD may be contraindicated. Prospective studies are warranted to determine whether this association may be causal.

Associations between Psychiatric Disorders and Cannabis-Related Disorders Documented in Electronic Health Records

Data from a large network of community health centers connected via a single electronic health record (EHR) system examined associations between psychiatric disorders and documentation of a cannabis-related disorder among patients with reported cannabis use. Participants were adults who had at least one ambulatory visit at a clinic in three states between 1/1/2012 and 12/31/2016 and had either 1) a documented cannabis-related disorder indicated by an ICD-9/10 code on the problem list or encounter list or 2) documentation of cannabis use in the EHR social history section. Clinics included 101,405 patients with either cannabis use recorded in the social history of the EHR (n = 71,660) or a cannabis-related disorder documented in the encounter or problem list (n = 29,745). GEE logistic regression modeling estimated adjusted odds ratios (aOR). Odds of patients having cannabis-related disorder recorded on the encounter or problem list were higher for individuals with depression (aOR = 1.08, 95% CI: 1.04-1.13), anxiety (aOR = 1.16, CI: 1.11-1.21) and bipolar disorder (aOR = 1.16, CI: 1.10-1.23). A diagnosis of schizophrenia increased the odds of a cannabis-related disorder by 62% (aOR = 1.62, CI: 1.48- 1.78). Primary care providers should routinely screen for and document cannabis-related disorders and psychiatric disorders.

Cannabis Use and Internalizing/Externalizing Symptoms in Youth: A Canadian Population-Based Study

PURPOSE

With the recent legalization of cannabis for nonmedicinal purposes in Canada, it is becoming increasingly important to understand the potential mental health risks that cannabis may present. The objective of this study was to estimate associations between the frequency of cannabis use and the presence of elevated internalizing (e.g., anxiety and depression) and externalizing (e.g., conduct disorder and attention deficit hyperactivity disorder) symptoms within Ontario youth aged 12-17 years.

METHODS

The 2014 Ontario Child Health Study included Emotional and Behavioural Scales used to assess internalizing and externalizing symptoms. To assess associations between internalizing/externalizing symptoms and cannabis use, the Ontario Child Health Study-Emotional and Behavioural Scales were dichotomized using the upper quintile (those with the most severe symptoms). Logistic regression was used to estimate odds ratios (ORs) to quantify the association between the frequency of cannabis use and the presence of elevated internalizing and externalizing symptoms. Estimates used a recommended procedure (replicate bootstrap weighting) to address design effects.

RESULTS

A significant association between frequent cannabis use and elevated externalizing symptoms was observed with an OR of 2.17 (1.80-2.62) in males and 5.13 (4.24-6.21) in females. Similar significant associations were also observed between frequent cannabis use and elevated internalizing symptoms with an OR of 2.07 (1.74-2.47) in males and an OR of 3.40 (2.73-4.24) in females. These associations were still present after adjusting for age, binge drinking, smoking, and negative/positive parenting.

CONCLUSIONS

Cannabis use, especially in females and frequent users, is associated with elevated levels of internalizing and externalizing symptoms.

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.

Cannabis use: A co-existing condition in first-episode bipolar mania patients

BACKGROUND

An association between first-episode presentation of bipolar mania and concurrent cannabis use disorder has been well established in the current literature (Bally et al., 2014, Baethge et al., 2008). Previous studies have shown that 30-70% of patients admitted for a first manic episode had concurrent cannabis use (Bally et al., 2014). The exact mechanism of this association has yet to be confirmed.

AIMS

We aim to evaluate the prevalence of cannabis use in patients with bipolar disorder (BD) admitted to UTHealth Harris County Psychiatric Center (HCPC) for a first manic episode.

METHODS

In this retrospective cohort study, 15,969 inpatient records of patients admitted to HCPC between 2012-2013 were examined to identify patients admitted with a first manic episode according to ICD-9 criteria (single episode mania). The prevalence of multiple sociodemographic and clinical variables including cannabis positivity in urine drug screening (UDS) were examined.

RESULTS

Twenty patients were admitted for a first manic episode. Half of the patients were females; mean age was 28.65 ± 10.56 years and mean length of stay (LOS) was 7.15 ± 3.72 days. Fifteen patients received a UDS. Of these fifteen, seven were positive for cannabinoids (47%). One patient was positive for phencyclidine (in addition to cannabis) and one patient was positive for amphetamine (but not cannabis).

CONCLUSIONS

The prevalence of cannabis use was higher in first-episode mania patients compared to the general population. The influence of cannabis on the first episode of mania requires additional study.

Cannabis use in early adulthood is prospectively associated with prescriptions of antipsychotics, mood stabilizers, and antidepressants

OBJECTIVE

Cannabis is an acknowledged risk factor for some mental disorders, but for others the evidence is inconclusive. Prescribed medicinal drugs can be used as proxies for mental disorders. In this study, we investigate how use of cannabis is prospectively related to prescription of antipsychotics, mood stabilizers, antidepressants, and anxiolytics.

METHODS

Data on cannabis exposure and relevant confounders were obtained from 2,602 individuals in the longitudinal Young in Norway Study, providing survey data from four data collection waves between 1992 and 2006. Data were coupled with information about prescriptions for psychotropic drugs from the Norwegian Prescription Database between 2007 and 2015.

RESULTS

Past year cannabis use increased the risk of prescription of antipsychotics (OR = 5.56, 95 % CI 1.64 - 18.87), mood stabilizers (OR = 5.36, 95 % CI 1.99 - 14.44) and antidepressants (OR = 2.10, 95 % CI 1.36 - 3.25), after accounting for sociodemographic variables, conduct problems, additional drug use, mental distress, and prescriptions the year before cannabis use was measured.

CONCLUSIONS

In this study of young adults from the general population, past year cannabis use was associated with later prescriptions of antipsychotics, mood stabilizers, and antidepressants.

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.

Does cannabis use increase anxiety disorders? A literature review

PURPOSE OF REVIEW

Cannabis is widely used worldwide and cannabis use disorders are highly comorbid with anxiety disorders. In this review, we consider the recent literature on the effects of cannabis on the incidence, course, and treatment outcomes of anxiety disorders.

RECENT FINDINGS

Although cannabis use is mostly found to be associated with increased incidence of anxiety disorders, these findings are generally not sustained in adjusted analyses controlling for multiple confounders. There are some equivocal data suggesting higher risk for anxiety disorders among heavy cannabis users. The scarce data available indicates no clear effect of cannabis use on the course and treatment outcomes of anxiety disorders.

SUMMARY

Further research is needed focusing on trajectories of cannabis-induced acute anxiety, effects of cannabis use on treatment outcomes in anxiety disorders, and common genetic factors. Future epidemiological studies should utilize more precise measures of cannabis use and address several confounding factors which may affect the association between cannabis use and anxiety disorders.

An International Society of Bipolar Disorders task force report: Precursors and prodromes of bipolar disorder

OBJECTIVES

To clarify the clinical features preceding the onset of bipolar disorder (BD) has become a public health priority for the prevention of high morbidity and mortality. BD remains frequently under- or misdiagnosed, and under- or mistreated, often for years.

METHODS

We assessed the predictive value of precursors and prodromes of BD. We assessed precursors of first-lifetime manic or hypomanic episodes with/without mixed features in retrospective and prospective studies. The task force evaluated and summarized separately assessments of familial risk, premorbid personality traits, retrospective, and prospective studies.

RESULTS

Cyclothymic features, a family history of BD, retrospectively reported attenuated manic symptoms, prospectively identified subthreshold symptoms of hypomania, recurrence of depression, panic anxiety and psychotic features, have been identified as clinical precursors of BD. The prodromal symptoms like [hypo]mania often appears to be long enough to encourage early identification and timely intervention.

CONCLUSIONS

The predictive value of any risk factor identified remains largely unknown. Prospective controlled studies are urgently needed for prevention and effective treatment.

Bipolar disorder and the endocannabinoid system

OBJECTIVE

Bipolar disorder (BD) is a debilitating, lifelong neuropsychiatric illness characterised by unsteady mood states which vacillate from (hypo)mania to depression. Despite the availability of pharmaceutical agents which can be effective in ameliorating the acute affective symptoms and prevent episodic relapse, BD is inadequately treated in a subset of patients. The endocannabinoid system (ECS) is known to exert neuromodulatory effects on other neurotransmitter systems critical in governing emotions. Several studies ranging from clinical to molecular, as well as anecdotal evidence, have placed a spotlight on the potential role of the ECS in the pathophysiology of BD. In this perspective, we present advantages and disadvantages of cannabis use in the management of illness course of BD and provide mechanistic insights into how this system might contribute to the pathophysiology of BD.

RESULTS

We highlight the putative role of selective cannabinoid receptor 2 (CB2) agonists in BD and briefly discuss findings which provide a rationale for targeting the ECS to assuage the symptoms of BD. Further, data encourage basic and clinical studies to determine how cannabis and cannabinoids (CBs) can affect mood and to investigate emerging CB-based options as probable treatment approaches.

CONCLUSION

The probable role of the ECS has been almost neglected in BD; however, from data available which suggest a role of ECS in mood control, it is justified to support conducting comprehensive studies to determine whether ECS manipulation could positively affect BD. Based on the limited available data, we suggest that activation of CB2 may stabilise mood in this disorder.

Synthetic cannabinoid use disorder: an update for general psychiatrists

OBJECTIVE

Synthetic cannabinoid use disorder is emerging as a significant clinical issue. This article provides the general psychiatrist with an overview of the physical and psychiatric adverse effects of chronic synthetic cannabinoid use, as well as specific clinical responses.

METHOD

We performed electronic searches of Ovid MEDLINE and Ovid Embase to identify key articles, of all methodological designs, published up to June 2018.

RESULTS

The available evidence suggests that, compared to cannabis, use of synthetic cannabinoids is associated with the more rapid development of dependence, increased psychiatric risks and complex withdrawal, and serious physical adverse effects that include seizures, cardiotoxicity and death, denoting a potential need for more intensive management.

CONCLUSION

When synthetic cannabinoid use is identified, along with management of acute physical and psychiatric adverse effects, psychotherapeutic strategies to reduce use and/or harm are recommended.

A longitudinal analysis of cannabis use and mental health symptoms among gay, bisexual, and other men who have sex with men in Vancouver, Canada

BACKGROUND

Cannabis use, anxiety, and depression are common among gay, bisexual, and other men who have sex with men (gbMSM) and some report using cannabis to manage mental health symptoms.

METHODS

Sexually-active gbMSM aged ≥16 years were recruited into a longitudinal cohort through respondent-driven sampling and completed study visits every six months. Data on demographics, drug use, and anxiety and depression symptoms were collected via a self-administered computer-based survey. A study nurse determined previous mental health diagnoses and treatment. Using multivariable generalized linear mixed models, we examined factors associated with regular cannabis use (≥weekly in the previous 3 months) and, among individuals who reported anxiety or depression/bipolar diagnoses, factors associated with moderate/severe anxiety or depression symptoms.

RESULTS

Of 774 participants (551 HIV-negative, 223 HIV-seropositive), 250 (32.3%) reported regular cannabis use, 200 (26.4%) reported ever being diagnosed with anxiety, and 299 (39.3%) reported ever being diagnosed with depression or bipolar disorder at baseline. Regular cannabis use was positively associated with HIV-seropositivity (aOR = 2.23, 95%CI:1.40-3.54) and previous mental health diagnosis (aOR = 1.52, 95%CI: 1.00-2.31, p = 0.05). Among those previously diagnosed with anxiety or depression/bipolar disorder, regular cannabis use was not associated with moderate/severe anxiety (aOR = 1.16, 95%CI:0.69-1.94) or depression symptoms (aOR = 0.96, 95%CI:0.59-1.58), respectively.

LIMITATIONS

Because of observational study design, we are unable to determine absolute effect.

CONCLUSIONS

Regular cannabis use was more likely among HIV-positive gbMSM and those previously diagnosed with a mental health disorder. No association was found between regular cannabis use and severity of anxious or depressive symptoms among those diagnosed with these conditions.

Clinical and Environmental Risk Factors for Bipolar Disorder: Review of Prospective Studies

After participating in this activity, learners should be better able to:• Evaluate factors that have been identified in prospective studies as predicting the onset of bipolar disorder ABSTRACT: The prodromal phase of bipolar disorder (BD) remains incompletely characterized, limiting early detection of BD and delaying interventions that might limit future morbidity and disability. Retrospective and family-risk studies have consistently found evidence of prodromal psychopathology in subjects later diagnosed with BD. Here, we review prospective studies of clinical risk factors and exposures identified before diagnosis of BD: our findings are consistent with those from retrospective and family-risk studies. Affective psychopathology often precedes diagnosis to suggest a homotypic trajectory in developing BD. Early non-affective (heterotypic) psychopathological disturbances, including anxiety and disruptive behavior disorders, as well as environmental factors and exposures, have been found in prospective studies to increase the risk of BD, but tend to lack specificity in predicting BD. Findings from prospective studies are encouragingly similar to those of retrospective and family-risk studies.

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.

A Reciprocal Model of Pain and Substance Use: Transdiagnostic Considerations, Clinical Implications, and Future Directions

Pain and substance use are highly prevalent and co-occurring conditions that continue to garner increasing clinical and empirical interest. Although nicotine and tobacco, alcohol, and cannabis each confer acute analgesic effects, frequent or heavy use may contribute to the development and progression of chronic pain, and pain may be heightened during abstinence. Additionally, pain can be a potent motivator of substance self-administration, and it may contribute to escalating use and poorer substance-related treatment outcomes. We integrated converging lines of evidence to propose a reciprocal model in which pain and substance use are hypothesized to interact in the manner of a positive feedback loop, resulting in the exacerbation and maintenance of both conditions over time. Theoretical mechanisms in bidirectional pain-substance use relations are reviewed, including negative reinforcement, social cognitive processes, and allostatic load in overlapping neural circuitry. Finally, candidate transdiagnostic factors are identified, and we conclude with a discussion of clinical implications and future research directions.

Marijuana Use and Depressive Symptoms; Gender Differences in African American Adolescents

Introduction: This study aimed to examine gender differences in the bidirectional associations between marijuana use and depressive symptoms among African American adolescents. The study also tested gender differences in the effects of socioeconomic status, maternal support, and friends' drug use on adolescents' depressive symptoms and marijuana use. Methods: This is a secondary analysis of the Flint Adolescent Study (FAS). Six hundred and eighty one African American adolescents (335 males and 346 females) were followed for 3 years, from 1995 (mean age 16) to 1997 (mean age 19). Depressive symptoms (Brief Symptom Inventory) and marijuana use were measured annually during the follow up. We used multi-group latent growth curve modeling to explore the reciprocal associations between depressive symptoms and marijuana use over time based on gender. Results: Baseline marijuana use was predictive of an increase in depressive symptoms over time among male but not female African American adolescents. Baseline depressive symptoms were not predictive of an increase in marijuana use among male or female adolescents. Conclusion: Study findings suggest that male African American adolescents who use marijuana are at an increased risk of subsequent depressive symptoms. Interventions that combine screening and treatment for marijuana use and depression may be indicated for African American male adolescents.