Cannabis Use and the Risk for Psychosis and Affective Disorders

The Role of Social Deprivation and Cannabis Use in Explaining Variation in the Incidence of Psychotic Disorders: Findings From the EU-GEI Study

BACKGROUND AND HYPOTHESIS

Recent findings suggest the incidence of first-episode psychotic disorders (FEP) varies according to setting-level deprivation and cannabis use, but these factors have not been investigated together. We hypothesized deprivation would be more strongly associated with variation in FEP incidence than the prevalence of daily or high-potency cannabis use between settings.

STUDY DESIGN

We used incidence data in people aged 18-64 years from 14 settings of the EU-GEI study. We estimated the prevalence of daily and high-potency cannabis use in controls as a proxy for usage in the population at-risk; multiple imputations by chained equations and poststratification weighting handled missing data and control representativeness, respectively. We modeled FEP incidence in random intercepts negative binomial regression models to investigate associations with the prevalence of cannabis use in controls, unemployment, and owner-occupancy in each setting, controlling for population density, age, sex, and migrant/ethnic group.

STUDY RESULTS

Lower owner-occupancy was independently associated with increased FEP (adjusted incidence rate ratio [aIRR]: 0.76, 95% CI: 0.61-0.95) and non-affective psychosis incidence (aIRR: 0.68, 95% CI: 0.55-0.83), after multivariable adjustment. Prevalence of daily cannabis use in controls was associated with the incidence of affective psychoses (aIRR: 1.53, 95% CI: 1.02-2.31). We found no association between FEP incidence and unemployment or high-potency cannabis use prevalence. Sensitivity analyses supported these findings.

CONCLUSIONS

Lower setting-level owner-occupancy and increased prevalence of daily cannabis use in controls independently contributed to setting-level variance in the incidence of different psychotic disorders. Public health interventions that reduce exposure to these harmful environmental factors could lower the population-level burden of psychotic disorders.

S.. Knowledge, Attitude, and Expectancies Related to Cannabis Use: A Cross-sectional Community Study Among College Students from Bangalore, Karnataka

Background

Cannabis use among youth is increasing; this study aimed to assess college students' knowledge, attitude, and expectancies toward cannabis use.

Methods

Cross-sectional survey using standardized tools among undergraduate and postgraduate college students in urban Bangalore, India (N = 405).

Results

Ten percent reported past three-month cannabis use, with 1% reporting daily use. Users were significantly older (median age 21, IQR 22,20 [vs. 20, IQR 21,19], p < .001) and belonged to families with higher monthly incomes (p = .02). Use was significantly higher among males than females (65.9% vs. 34.1%, p = .006) and postgraduate students than undergraduates (51.2% vs. 48%, p = .001). Users were also significantly more favorable toward cannabis use (median score 4, IQR 6,2 [vs. median 3, IQR 4,2], p = .005) and had more positive expectancies from use (median score 2, IQR 3,2 [vs. median 2, IQR 2,0], p = .001). Nearly 30% were unaware that cannabis can affect a person's ability to drive safely or that it can affect executive functions, including academic performance. Over one-third were unaware of the current legal status of cannabis in India. Overall, 36%, 25%, and 17%, respectively, said that cannabis use is safe when used for recreational purposes, cannabis should be legalized as it helps to relieve stress, and cannabis use among youngsters should be acceptable in society as it is "part of college life."

Conclusion

Findings build on existing literature on cannabis use among college youth in India, which can guide preventive interventions and policies for this vulnerable group.

The risk of cannabis use disorder is mediated by altered brain connectivity: A chronnectome study

The brain mechanisms underlying the risk of cannabis use disorder (CUD) are poorly understood. Several studies have reported changes in functional connectivity (FC) in CUD, although none have focused on the study of time-varying patterns of FC. To fill this important gap of knowledge, 39 individuals at risk for CUD and 55 controls, stratified by their score on a self-screening questionnaire for cannabis-related problems (CUDIT-R), underwent resting-state functional magnetic resonance imaging. Dynamic functional connectivity (dFNC) was estimated using independent component analysis, sliding-time window correlations, cluster states and meta-state indices of global dynamics and were compared among groups. At-risk individuals stayed longer in a cluster state with higher within and reduced between network dFNC for the subcortical, sensory-motor, visual, cognitive-control and default-mode networks, relative to controls. More globally, at-risk individuals had a greater number of meta-states and transitions between them and a longer state span and total distance between meta-states in the state space. Our findings suggest that the risk of CUD is associated with an increased dynamic fluidity and dynamic range of FC. This may result in altered stability and engagement of the brain networks, which can ultimately translate into altered cortical and subcortical function conveying CUD risk. Identifying these changes in brain function can pave the way for early pharmacological and neurostimulation treatment of CUD, as much as they could facilitate the stratification of high-risk individuals.

Development and initial validation of the cannabis-related psychosis risk literacy scale (CPRL): a multinational psychometric study

BACKGROUND

Public education efforts to address and reduce potential harms from cannabis use in Arab countries are either slow or inexistent, and do not follow the steadily increasing trends of cannabis use in Arab youth. Several decades of research on substance use, it can be suggested that being aware of, and knowing about, psychosis risk related to cannabis can at least limit the consumption of the substance. Motivated by a lack of measures specifically designed to measure literacy about cannabis-related psychosis risk in younger populations, and based on an extensive literature review, we aimed to create and validate a new self-report scale to assess the construct, the Cannabis-related Psychosis Risk Literacy Scale (CPRL), in the Arabic language.

METHOD

A cross-sectional study was carried-out during the period from September 2022 to June 2023, enrolling 1855 university students (mean age of 23.26 ± 4.96, 75.6% females) from three Arab countries (Egypt, Kuwait and Tunisia).

RESULTS

Starting from an initial pool of 20 items, both Exploratory Factor Analysis and Confirmatory Factor Analysis suggested that the remaining 8 items loaded into a single factor. The scale demonstrated good internal consistency, with both McDonald omega and Cronbach's alpha values exceeding 0.7 (omega = 0.85 / alpha = 0.85). The CPRL showed measurement invariance across gender and country at the configural, metric, and scalar levels. Concurrent validity of the CPRL was established by correlations with less favourable attitudes towards cannabis (r = -.14; p <.001). In addition, higher literacy levels were found in students who never used cannabis compared to lifetime users (4.18 ± 1.55 vs. 3.44 ± 1.20, t(1853) = 8.152, p <.001).

CONCLUSION

The newly developed CPRL scale offers a valid and reliable instrument for assessing and better understanding literacy about cannabis-related psychosis risk among Arabic-speaking young adults. We believe that this new scale is suitable as a screening tool of literacy, as an instrument for measuring the effect of public education interventions aimed at promoting cannabis-related psychosis risk literacy among young people, and as a research tool to facilitate future studies on the topic with a wider application.

Cannabis use and cannabis use disorders and their treatment in the Europe

This paper introduces the special issue on cannabis use in Europe. It describes data on the prevalence of cannabis use in Europe and the more limited data on the prevalence of cannabis use disorders, one of the most common forms of drug problem treated in many countries in Europe. It summarises what research has indicated about the adverse effects of acute and chronic cannabis use and discusses potential health system responses that may reduce some of these harms. These include public education about the risks of cannabis use; screening and brief interventions in primary medical settings; and specialist treatment for cannabis use disorders. It briefly indicates the special issues that may need to be addressed in dealing with the high rates of comorbidity between cannabis use disorders, other types of drug use disorders, and common mental disorders.

The effect of non-medical cannabis retailer proximity on use of mental health services for psychotic disorders in Ontario, Canada

BACKGROUND

Cannabis is associated with the onset and persistence of psychotic disorders. Evidence suggests that accessibility of substances is associated with an increased risk of use-related harms. We sought to examine the effect of residing in proximity to non-medical cannabis retailers on the prevalence of health service use for psychosis.

METHODS

We conducted a cross-sectional study using linked health administrative data, and used geospatial analyses to determine whether people in Ontario, Canada (aged 14-60 years) resided within walking (1.6 km) or driving (5.0 km) distance of non-medical cannabis retailers (open as of February-2020). We identified outpatient visits, emergency department (ED) visits, and hospitalizations for psychotic disorders between 01-April-2019 and 17-March-2020. We used zero-inflated Poisson regression models and gamma generalized linear models to estimate the association between cannabis retailer proximity and indicators of health service use.

RESULTS

Non-medical cannabis retailers were differentially located in areas with high levels of marginalization and pre-existing health service use for psychosis. People residing within walking or driving distance of a cannabis retailer had a higher rate of psychosis-related outpatient visits, ED visits, and hospitalizations, compared to people living outside these areas. This effect was stronger among those with no prior service use for psychosis.

CONCLUSIONS

Proximity to a non-medical cannabis retailer was associated with higher health service use for psychosis, even after adjustment for prior health service use. These findings suggest that opening of non-medical cannabis retailers could worsen the burden of psychosis on mental health services in areas with high-risk populations.

Recurrent cannabis-induced catatonia: a case report and comprehensive systematic literature review

Background

Catatonia presents itself as a complex neuropsychiatric syndrome, giving rise to various motor, speech, and behavioral challenges. It is noteworthy that approximately 10% of psychiatric hospital admissions can be attributed to this condition. It is imperative to note that cannabis-induced catatonia, while infrequent, has been linked to the use of marijuana. This connection has the potential to disrupt neurotransmitter systems, necessitating further research for a comprehensive understanding and effective treatment, particularly given the evolving trends in cannabis use. In this context, we shall delve into a unique case of recurrent cannabis-induced catatonia.

Case presentation

A 23-year-old gentleman, who has previously struggled with substance use disorder, experienced the emergence of mutism, social isolation, and a fixed gaze subsequent to his use of cannabis. Remarkably, despite the absence of hallucinations, he exhibited recurrent episodes of catatonia. These episodes were effectively addressed through a combination of electroconvulsive therapy (ECT) and lorazepam administration. Notably, when the lorazepam dosage was gradually reduced to below 2 mg per day, the catatonic symptoms resurfaced; however, they promptly abated upon reinstating the medication. The diagnosis of cannabis-induced catatonia was established, and its management primarily involved a therapeutic approach encompassing ECT and lorazepam. It is pertinent to underscore that this catatonic condition can be directly linked to the individual's cannabis usage.

Conclusion

The connection between cannabis and catatonia is intricate and not entirely comprehended. Although cannabis possesses therapeutic advantages, it can paradoxically trigger catatonia in certain individuals. Multiple factors, such as genetics, cannabinoids, and neurotransmitter systems, contribute to this intricacy, underscoring the necessity for additional research.

Psychosis superspectrum I: Nosology, etiology, and lifespan development

This review describes the Hierarchical Taxonomy of Psychopathology (HiTOP) model of psychosis-related psychopathology, the psychosis superspectrum. The HiTOP psychosis superspectrum was developed to address shortcomings of traditional diagnoses for psychotic disorders and related conditions including low reliability, arbitrary boundaries between psychopathology and normality, high symptom co-occurrence, and heterogeneity within diagnostic categories. The psychosis superspectrum is a transdiagnostic dimensional model comprising two spectra-psychoticism and detachment-which are in turn broken down into fourteen narrow components, and two auxiliary domains-cognition and functional impairment. The structure of the spectra and their components are shown to parallel the genetic structure of psychosis and related traits. Psychoticism and detachment have distinct patterns of association with urbanicity, migrant and ethnic minority status, childhood adversity, and cannabis use. The superspectrum also provides a useful model for describing the emergence and course of psychosis, as components of the superspectrum are relatively stable over time. Changes in psychoticism predict the onset of psychosis-related psychopathology, whereas changes in detachment and cognition define later course. Implications of the superspectrum for genetic, socio-environmental, and longitudinal research are discussed. A companion review focuses on neurobiology, treatment response, and clinical utility of the superspectrum, and future research directions.

Aberrant salience in cannabis-induced psychosis: a comparative study

Background

Natural Cannabis (NC) and Synthetic Cannabinoids (SCs) use can increase the risk and exacerbate the course of psychotic disorders. These could be influenced by the Aberrant Salience (AS) construct. It refers to an excess of attribution of meaning to stimuli that are otherwise regarded as neutral, thereby transform them into adverse, dangerous, or mysterious entities. This leads the patient to engage in aberrant and consequently incorrect interpretative efforts concerning the normal perception of reality and its relationship with our analytical abilities. AS appears to play a significant role in the onset and perpetuation of psychotic disorders. The internal conflict arising from aberrant attributions of significance leads to delusional thoughts, ultimately culminating in the establishment of a self-sustaining psychosis.

Aims

To examine the differences between psychoses course not associated with cannabis use and those associated with NC-use and SCs-use, in terms of psychotic and dissociative symptoms, AS, global functioning and suicidal ideation.

Methods

A sample of 62 patients with First Episode Psychosis (FEP) was divided into 3 groups: non cannabis users (non-users, N = 20); NC-users or rather Delta-9-tetrahydrocannabinol (THC) users (THC-users, N = 21); SCs-users, commonly referred to as SPICE-users (SPICE-users, N = 20). Each group underwent assessments at the onset of psychotic symptoms, as well as at the 3 months and 6 months marks, utilizing a range of psychopathological scales. These included the Positive and Negative Syndrome Scale (PANSS) for investigating psychotic symptoms, the Global Assessment of Functioning (GAF) scale for assessing overall functioning, the Dissociative Experiences Scale (DES-II) for measuring dissociative symptoms, the Scale for Suicide Ideation (SSI) for evaluating suicidal ideation and the Aberrant Salience Inventory (ASI) scale for gauging AS.

Results

SPICE-users showed more severe and persistent positive symptoms, while negative symptoms were mostly represented among non-users. Non-users showed better recovery than SPICE-users in global functioning. All groups showed a decrease in both ASI scores and subscale scores. SPICE-users exhibited higher global AS scores and less improvement in this aspect compared to other groups.

Conclusion

This study may help understanding the role of AS in both non-substance-related and substance-induced psychosis. This knowledge may lead clinician to a better diagnosis and identify patient-tailored psychopharmacological treatment.

Unhealthy behaviors associated with mental health disorders: a systematic comparative review of diet quality, sedentary behavior, and cannabis and tobacco use

Background

There are well-established literatures documenting the associations between mental disorders and unhealthy behaviors such as poor diet quality, sedentary behavior, and cannabis and tobacco use. Few studies have attempted to understand the respective findings in light of each other, however.

Objective

The purpose of this review was to assemble comparable data for each behavior-disorder association and assess the associations in terms of their overall strength. The review aimed to include a representative, but not exhaustive, range of studies that would allow for explorative comparisons.

Methods

Eligible studies were identified via Pubmed searches and citation searching, restricted to publications no older than 2015 written in English. To obtain comparable data, only studies that reported findings as odds ratios were included, and risk of bias related to study samples, behavioral measurement disparities, and control variables was assessed via sensitivity analyses. Findings for each disorder were compared on the basis of different measures of central tendency.

Results

From 3,682 records, 294 studies were included. The review found evidence of associations between each of the four unhealthy behaviors and psychosis, depression, anxiety, bipolar disorder, attention-deficit/hyperactivity disorder (ADHD), and post-traumatic stress disorder (PTSD), while personality disorder was only investigated in relation to cannabis and tobacco use. In overall comparison, the associations were generally of similar strength, and only the association between cannabis use and personality disorder was exceptional in terms of being significantly stronger than its counterparts across disorders and across behaviors. Analyses of bias risk identified some influence from behavioral measurement disparities and lack of adequate statistical control, but findings were generally robust across a range of sensitivity analyses.

Conclusion

This explorative and comparative review found that poor diet quality, sedentary behavior, and cannabis and tobacco use are about equally strongly associated with a range of different mental disorders. Given the general nature of these associations, we should probably understand them to reflect a general and shared etiology. However, the findings in this review should be regarded as tentative until confirmed by more comprehensive investigations.

Impact of non-medical cannabis legalization with market restrictions on health service use and incident cases of psychotic disorder in Ontario, Canada

BACKGROUND

Cannabis is a risk factor in the onset and persistence of psychotic disorders. There is concern that non-medical cannabis legalization in Canada may have population-level impacts on psychotic disorders. We sought to examine changes in health service use and incident cases of psychotic disorder following cannabis legalization, during a period of tight restrictions on retail stores and product types.

METHODS

We conducted a cross-sectional interrupted time-series analysis using linked population-based health administrative data from Ontario (Canada) from January 2014 to March 2020. We identified psychosis-related outpatient visits, emergency department visits, hospitalizations, and inpatient length of stay, as well as incident cases of psychotic disorders, among people aged 14 to 60 years.

RESULTS

We did not find evidence of increases in health service use or incident cases of psychotic disorders over the short-term (17 month) period following cannabis legalization. However, we found clear increasing trends in health service use and incident cases of substance-induced psychotic disorders over the entire observation window (2014-2020).

CONCLUSION

Our findings suggest that the initial period of tight market restriction following legalization of non-medical cannabis was not associated with an increase in health service use or frequency of psychotic disorders. A longer post-legalization observation period, which includes expansion of the commercial cannabis market, is needed to fully understand the population-level impacts of non-medical cannabis legalization; thus, it would be premature to conclude that the legalization of non-medical cannabis did not lead to increases in health service use and incident cases of psychotic disorder.

Differential associations of adolescent versus young adult cannabis initiation with longitudinal brain change and behavior

Leveraging ~10 years of prospective longitudinal data on 704 participants, we examined the effects of adolescent versus young adult cannabis initiation on MRI-assessed cortical thickness development and behavior. Data were obtained from the IMAGEN study conducted across eight European sites. We identified IMAGEN participants who reported being cannabis-naïve at baseline and had data available at baseline, 5-year, and 9-year follow-up visits. Cannabis use was assessed with the European School Survey Project on Alcohol and Drugs. T1-weighted MR images were processed through the CIVET pipeline. Cannabis initiation occurring during adolescence (14-19 years) and young adulthood (19-22 years) was associated with differing patterns of longitudinal cortical thickness change. Associations between adolescent cannabis initiation and cortical thickness change were observed primarily in dorso- and ventrolateral portions of the prefrontal cortex. In contrast, cannabis initiation occurring between 19 and 22 years of age was associated with thickness change in temporal and cortical midline areas. Follow-up analysis revealed that longitudinal brain change related to adolescent initiation persisted into young adulthood and partially mediated the association between adolescent cannabis use and past-month cocaine, ecstasy, and cannabis use at age 22. Extent of cannabis initiation during young adulthood (from 19 to 22 years) had an indirect effect on psychotic symptoms at age 22 through thickness change in temporal areas. Results suggest that developmental timing of cannabis exposure may have a marked effect on neuroanatomical correlates of cannabis use as well as associated behavioral sequelae. Critically, this work provides a foundation for neurodevelopmentally informed models of cannabis exposure in humans.

The endocannabinoid system as a putative target for the development of novel drugs for the treatment of psychiatric illnesses

Cannabis is well established to impact affective states, emotion and perceptual processing, primarily through its interactions with the endocannabinoid system. While cannabis use is quite prevalent in many individuals afflicted with psychiatric illnesses, there is considerable controversy as to whether cannabis may worsen these conditions or provide some form of therapeutic benefit. The development of pharmacological agents which interact with components of the endocannabinoid system in more localized and discrete ways then via phytocannabinoids found in cannabis, has allowed the investigation if direct targeting of the endocannabinoid system itself may represent a novel approach to treat psychiatric illness without the potential untoward side effects associated with cannabis. Herein we review the current body of literature regarding the various pharmacological tools that have been developed to target the endocannabinoid system, their impact in preclinical models of psychiatric illness and the recent data emerging of their utilization in clinical trials for psychiatric illnesses, with a specific focus on substance use disorders, trauma-related disorders, and autism. We highlight several candidate drugs which target endocannabinoid function, particularly inhibitors of endocannabinoid metabolism or modulators of cannabinoid receptor signaling, which have emerged as potential candidates for the treatment of psychiatric conditions, particularly substance use disorder, anxiety and trauma-related disorders and autism spectrum disorders. Although there needs to be ongoing clinical work to establish the potential utility of endocannabinoid-based drugs for the treatment of psychiatric illnesses, the current data available is quite promising and shows indications of several potential candidate diseases which may benefit from this approach.

Do Anxiety Symptoms Mediate the Association Between Cannabis Use Frequency and Psychotic-Like Experiences in Emerging Adult Undergraduates?

OBJECTIVE

Cannabis is commonly used by Canadian emerging adults (ages 18-25 years), many of whom attend post-secondary institutions. Frequent cannabis use is linked with psychotic-like experiences (PLEs); however, the exact nature of this association remains unclear. Anxiety symptoms may mediate this association, as they are prevalent in emerging adults and have been independently linked with both cannabis use and PLEs. Past work found that anxiety mediated the association between cannabis use frequency and attenuated positive psychotic symptoms (further along the psychosis continuum than PLEs), however this research had yet to be validated in the Canadian population, and trait rather than state anxiety (frequency of anxiety symptoms) was studied. Thus, our primary objective was to examine if anxiety symptoms mediated the association between cannabis use frequency and PLEs in Canadian emerging adult undergraduates. Despite known sex differences in cannabis use, expression of anxiety, and PLEs, past work did not evaluate the potential impact of biological sex on the anxiety-mediated model, and thus is the secondary objective of the present study.

METHODS

1,266 first-/second-year emerging adult undergraduates from five Canadian universities provided cross-sectional, self-report survey data in fall 2021 semester. Validated measures of cannabis use frequency, anxiety, and PLEs were administered.

RESULTS

Path analyses supported mediation from cannabis use to PLEs through anxiety (b  =  0.07, P < 0.001, 95% bootstrap CI [0.03, 0.10]). No direct effect was found (P  =  0.457), suggesting that the cannabis-to-PLEs association was mediated by anxiety. Mediation did not depend on biological sex (i.e., bootstrapped 95% CIs crossed zero).

CONCLUSIONS

Anxiety symptoms mediated the association between cannabis use and PLEs in emerging adults regardless of their biological sex. Assuming replication in prospective research, results highlight anxiety as an important intervention target in frequent cannabis-using emerging adults, to potentially prevent development/worsening of PLEs, and in turn psychotic illness.

Association of cannabis, cannabidiol and synthetic cannabinoid use with mental health in UK adolescents

BACKGROUND

Cannabis has been associated with poorer mental health, but little is known of the effect of synthetic cannabinoids or cannabidiol (often referred to as CBD).

AIMS

To investigate associations of cannabis, synthetic cannabinoids and cannabidiol with mental health in adolescence.

METHOD

We conducted a cross-sectional analysis with 13- to 14-year-old adolescents across England and Wales in 2019-2020. Multilevel logistic regression was used to examine the association of lifetime use of cannabis, synthetic cannabinoids and cannabidiol with self-reported symptoms of probable depression, anxiety, conduct disorder and auditory hallucinations.

RESULTS

Of the 6672 adolescents who participated, 5.2% reported using of cannabis, 1.9% reported using cannabidiol and 0.6% reported using synthetic cannabinoids. After correction for multiple testing, adolescents who had used these substances were significantly more likely to report a probable depressive, anxiety or conduct disorder, as well as auditory hallucinations, than those who had not. Adjustment for socioeconomic disadvantage had little effect on associations, but weekly tobacco use resulted in marked attenuation of associations. The association of cannabis use with probable anxiety and depressive disorders was weaker in those who reported using cannabidiol than those who did not. There was little evidence of an interaction between synthetic cannabinoids and cannabidiol.

CONCLUSIONS

To our knowledge, this study provides the first general population evidence that synthetic cannabinoids and cannabidiol are associated with probable mental health disorders in adolescence. These associations require replication, ideally with prospective cohorts and stronger study designs.

Integrating Substance Misuse Specialists in a Youth Early Psychosis Service: Increasing Mental Health Clinicians' Knowledge and Confidence

Substance misuse and mental health disorders are commonly occurring co-morbidities in young people. This paper reports on a pilot project to embed three specialist Alcohol and Other Drug (AoD) workers to be embedded in a youth early psychosis service to upskill mental health clinicians in managing substance misuse. Evaluation of the project used a mixed methods approach. Quantitative results showed that clinical staff members' knowledge of substance misuse, knowledge of AoD treatments and services, and overall confidence in working with young people with a substance misuse issue improved following implementation of the project. Qualitative results indicated four themes which emerged: defining the role of the AoD workers; support and upskilling of the mental health staff; openness and effective communication between the embedded workers and mental health teams; and barriers to collaboration. The results provide support for the embedding of specialist alcohol and drug workers in youth mental health services.

Emerging adult perceptions of higher-risk cannabis consumption behaviours

BACKGROUND

Emerging adults have the highest cannabis consumption rates in Canada and are among the most vulnerable to cannabis-related harms. Since certain cannabis consumption behaviours carry greater risks of harm, the Lower-Risk Cannabis Use Guidelines (LRCUG) provide harm reduction strategies. To address a critical gap in the literature, the current study examined emerging adults' awareness of the guidelines and perceptions of higher-risk cannabis consumption behaviours identified within the LRCUG.

METHODS

Emerging adults (N = 653) between the ages of 18-25 years were recruited from across Canada. Participants were presented with five vignettes depicting a character's cannabis consumption behaviours. Each vignette focused on a unique aspect of the character's consumption (frequency, polysubstance use, family history of mental illness, method of consumption, and potency). Participants were randomly assigned to one of three conditions within each of the five vignettes that were altered to capture varying levels of risk (e.g. weekly, almost daily, or daily consumption). Following each vignette, participants were asked to respond to four items relating to overall risk of harm, cognitive health, physical health, and mental health.

RESULTS

Participants perceived: (1) frequent consumption to be associated with greater risks than less frequent consumption; (2) simultaneous consumption of cannabis and tobacco as being associated with higher risk of harm, yet no difference between simultaneous consumption of cannabis and alcohol or cannabis consumption alone; (3) consuming cannabis with a family history of psychosis or substance use disorder as being associated with greater overall risk than consumption with no family history; (4) smoking and vaping cannabis as associated with more risk than ingesting edibles; and (5) higher-potency THC-dominant strains as being associated with more risk than lower-potency CBD-dominant strains, yet no difference between the two higher-potency THC-dominant strains.

CONCLUSIONS

While emerging adults seemed to appreciate the risks associated with some cannabis consumption behaviours, they had difficulty identifying appropriate levels of harm of other higher-risk behaviours. Through an improved understanding of emerging adult perceptions, effective education campaigns should be designed to improve the awareness of cannabis risks and encourage the uptake of harm reduction awareness and strategies.

Risk-thresholds for the association between frequency of cannabis use and the development of psychosis: a systematic review and meta-analysis

BACKGROUND

Epidemiological studies show a dose-response association between cannabis use and the risk of psychosis. This review aimed to determine whether there are identifiable risk-thresholds between the frequency of cannabis use and psychosis development.

METHODS

Systematic search of Embase, MEDLINE, PsycINFO, CINAHL, and Web of Science for relevant studies (1 January 2010-26 April 2021). Case-control or cohort studies that investigated the relationship between cannabis use and the risk of psychosis development that reported effect estimates [odds ratios (OR), hazard ratios (HR), risk ratios (RR)] or the raw data to calculate them, with information on the frequency of cannabis consumption were included. Effect estimates were extracted from individual studies and converted to RR. Two-stage dose-response multivariable meta-analytic models were utilized and sensitivity analyses conducted. The Newcastle Ottawa Scale was used to assess the risk of bias of included studies.

RESULTS

Ten original (three cohorts, seven case-control) studies were included, including 7390 participants with an age range of 12-65 years. Random-effect model meta-analyses showed a significant log-linear dose-response association between cannabis use frequency and psychosis development. A restricted cubic-splines model provided the best fit for the data, with the risk of psychosis significantly increasing for weekly or more frequent cannabis use [RR = 1.01, 95% confidence interval (CI) 0.93-1.11 yearly; RR = 1.10, 95% CI 0.97-1.25 monthly; RR = 1.35, 95% CI 1.19-1.52 weekly; RR = 1.76, 95% CI 1.47-2.12 daily].

CONCLUSION

Individuals using cannabis frequently are at increased risk of psychosis, with no significant risk associated with less frequent use. Public health prevention messages should convey these risk-thresholds, which should be refined through further work.

Inflammation Markers Among Schizophrenia Patients Who Use Cannabis

OBJECTIVES

The mechanism of inflammation of the immune system, for example, such circulatory markers as the neutrophil-to-lymphocyte ratio (NLR) and mean platelet volume (MPV), has been shown in many studies to be associated with schizophrenia. In addition, it has been shown that the cannabidiol component reduces the activation of the acquired immune system. This study examined the differences in the levels of NLR and MPV among schizophrenia patients with cannabis use versus those without.

METHODS

In 2019 to 2020, a retrospective cross-sectional study was conducted based on digital medical records. Demographic, clinical, and complete blood cell count data were collected from records of rehospitalization of active psychotic schizophrenia inpatients. Data on NLR, MPV values, and demographic and clinical characteristics were compared between the groups and according to the degree of prevalence of cannabis use.

RESULTS

No differences were found in the NLR and MPV values between the groups.

CONCLUSION

The results were contrary to our expectations. These results may be explained by the presentation of a "pseudo-balanced" picture created when multiple processes affect inflammatory indices.

Schizotypal traits in a large sample of high-school and university students from Tunisia: correlates and measurement invariance of the arabic schizotypal personality questionnaire across age and sex

BACKGROUND

The main goal of the present study was to examine the characteristics of schizotypal traits and their correlations with genetic (i.e., family history of mental illness), demographic (i.e., age, sex), environmental (e.g., income, urbanicity, tobacco/alcohol/cannabis use), and psychological (i.e., personal history of mental illness other than psychosis) factors in Tunisian high-school and university students. Our secondary goal was to contribute the literature by examining the factor structure and factorial invariance of the Arabic Schizotypal Personality Questionnaire (SPQ) across sex and age (adolescents [12-18 years] vs. young adults [18-35 years]) groups.

METHOD

This was a cross-sectional study involving 3166 students: 1160 (36.6%) high-school students (53.0% females, aged 14.9 ± 1.8); and 2006 (63.4%) university students (63.9% females, aged 21.8 ± 2.3). All students were asked to complete a paper-and-pencil self-administered questionnaire containing sociodemographic characteristics as well as the Arabic version of the SPQ.

RESULTS

The total sample yielded total SPQ scores of 24.1 ± 16.6 out of 74. The SPQ yielded good composite reliability as attested by McDonald's omega values ranging from .68 to .80 for all nine subscales. Confirmatory Factor Analysis indicated that fit of the 9-factor model of SPQ scores was acceptable. This model is invariant (at the configural, metric and structural levels) across sex and age. Except for "Odd or eccentric behavior", all schizotypy features were significantly higher among female students compared to males. Multivariable analyses showed that female sex, being a university student, lowest family incomes, tobacco use, and having a personal history of psychiatric illness were significantly associated with higher positive, negative and disorganized schizotypy subscales scores.

CONCLUSION

Future research still needs to confirm our findings and investigate the contribution of the identified factors in the development of clinical psychosis. We can also conclude that the Arabic SPQ is appropriate for measuring and comparing schizotypy across age and sex in clinical and research settings. These findings are highly relevant and essential for ensuring the clinical utility and applicability of the SPQ in cross-cultural research.

Associations between primary care recorded cannabis use and mental ill health in the UK: a population-based retrospective cohort study using UK primary care data

BACKGROUND

Cannabis use is a global public health issue associated with increased risks of developing mental health disorders, especially in young people. We aimed to investigate the relationships between cannabis exposure and risks of receiving mental illness diagnoses or treatment as outcomes.

METHODS

A population based, retrospective, open cohort study using patients recorded in 'IQVIA medical research data', a UK primary care database. Read codes were used to confirm patients with recorded exposure to cannabis use who were matched up to two unexposed patients. We examined the risk of developing three categories of mental ill health: depression, anxiety or serious mental illness (SMI).

RESULTS

At study entry, the exposed cohort had an increased likelihood of having experienced mental ill health [odds ratio (OR) 4.13; 95% confidence interval (CI) 3.99-4.27] and mental ill health-related prescription (OR 2.95; 95% CI 2.86-3.05) compared to the unexposed group. During the study period we found that exposure to cannabis was associated with an increased risk of developing any mental disorder [adjusted hazard ratio (aHR) 2.73; 95% CI 2.59-2.88], also noted when examining by subtype of disorder: anxiety (aHR 2.46; 95% CI 2.29-2.64), depression (aHR 2.34; 95% CI 2.20-2.49) and SMI (aHR 6.41; 95% CI 5.42-7.57). These results remained robust in sensitivity analyses.

CONCLUSION

These findings point to the potential need for a public health approach to the management of people misusing cannabis. However, there is a gross under-recording of cannabis use in GP records, as seen by the prevalence of recorded cannabis exposure substantially lower than self-reported survey records.

Recommendations for Reducing the Risk of Cannabis Use-Related Adverse Psychosis Outcomes: A Public Mental Health-Oriented Evidence Review

Objective: Cannabis use is increasingly normalized; psychosis is a major adverse health outcome. We reviewed evidence on cannabis use-related risk factors for psychosis outcomes at different stages toward recommendations for risk reduction by individuals involved in cannabis use. Methods: We searched primary databases for pertinent literature/data 2016 onward, principally relying on reviews and high-quality studies which were narratively summarized and quality-graded; recommendations were developed by international expert consensus. Results: Genetic risks, and mental health/substance use problem histories elevate the risks for cannabis-related psychosis. Early age-of-use-onset, frequency-of-use, product composition (i.e., THC potency), use mode and other substance co-use all influence psychosis risks; the protective effects of CBD are uncertain. Continuous cannabis use may adversely affect psychosis-related treatment and medication effects. Risk factor combinations further amplify the odds of adverse psychosis outcomes. Conclusions: Reductions in the identified cannabis-related risks factors-short of abstinence-may decrease risks of related adverse psychosis outcomes, and thereby protect cannabis users' health.

Adolescent suicidal behaviour in Namibia: a cross-sectional study of prevalence and correlates among 3,152 school learners aged 12-17 years

BACKGROUND

While adolescent suicidal behaviour (ideation, planning, and attempt) remains a global public health concern, available county-specific evidence on the phenomenon from African countries is relatively less than enough. The present study was conducted to estimate the 12-month prevalence and describe some of the associated factors of suicide behaviour among school-going adolescents aged 12-17 years old in Namibia.

METHODS

Participants (n = 4531) answered a self-administered anonymous questionnaire developed and validated for the nationally representative Namibia World Health Organization Global School-based Student Health Survey conducted in 2013. We applied univariate, bivariable, and multivariable statistical approaches to the data.

RESULTS

Of the 3,152 analytical sample, 20.2% (95% confidence interval [CI]: 18.3-22.2%) reported suicidal ideation, 25.2% (95% CI: 22.3-28.4%) engaged in suicide planning, and 24.5% (95% CI: 20.9-28.6%) attempted suicide during the previous 12 months. Of those who attempted suicide, 14.6% (95% CI: 12.5-16.9%) reported one-time suicide attempt, and 9.9% (95% CI: 8.1-12.1%) attempted suicide at least twice in the previous 12 months. The final adjusted multivariable models showed physical attack victimisation, bullying victimisation, loneliness, and parental intrusion of privacy as key factors associated with increased likelihood of suicidal ideation, planning, one-time suicide attempt, and repeated attempted suicide. Cannabis use showed the strongest association with increased relative risk of repeated attempted suicide.

CONCLUSION

The evidence highlights the importance of paying more attention to addressing the mental health needs (including those related to psychological and social wellness) of school-going adolescents in Namibia. While the current study suggests that further research is warranted to explicate the pathways to adolescent suicide in Namibia, identifying and understanding the correlates (at the individual-level, family-level, interpersonal-level, school context and the broader community context) of adolescent suicidal ideations and non-fatal suicidal behaviours are useful for intervention and prevention programmes.

THC and CBD: Villain versus Hero? Insights into Adolescent Exposure

Cannabis is the most used drug of abuse worldwide. It is well established that the most abundant phytocannabinoids in this plant are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). These two compounds have remarkably similar chemical structures yet vastly different effects in the brain. By binding to the same receptors, THC is psychoactive, while CBD has anxiolytic and antipsychotic properties. Lately, a variety of hemp-based products, including CBD and THC, have become widely available in the food and health industry, and medical and recreational use of cannabis has been legalized in many states/countries. As a result, people, including youths, are consuming CBD because it is considered “safe”. An extensive literature exists evaluating the harmful effects of THC in both adults and adolescents, but little is known about the long-term effects of CBD exposure, especially in adolescence. The aim of this review is to collect preclinical and clinical evidence about the effects of cannabidiol.

Clinical features and factors related to lifetime suicidal ideation and suicide attempts in patients who have had substance-induced psychosis across their lifetime

Suicidal behaviors are common among patients with substance use disorders (SUD). However, the prevalence and clinical factors related to suicide behaviors among patients who have had substance-induced psychosis (SIP) is unknown. This study aims to explore the prevalence, clinical features, and factors related to lifetime suicidal ideation (SI) and suicide attempts (SA) in patients who have had SIP across their lifetime. A cross-sectional study was conducted in an outpatient center for addiction treatment between 01/01/2010 and 12/31/2021. 601 patients were evaluated with validated scales and questionnaires (79.03% males; M age 38.11±10.11 years). The prevalence of SI and SA was 55.4% and 33.6%, respectively. SI was independently related to any type of lifetime abuse, depressive spectrum disorders, benzodiazepine use disorder, borderline personality disorder, and the level of depressive symptoms. SA was independently associated with lifetime physical abuse, benzodiazepine use disorder, the number of psychotic symptoms, borderline personality disorder, and the level of depressive symptoms. The main factors related to SI and SA in those patients should be evaluated in daily clinical practice and considered in any approach to clinical practice as well as in health policies targeting suicide prevention.

Neuroimaging revealed long-lasting glucose metabolism changes to morphine withdrawal in rats pretreated with the cannabinoid agonist CP-55,940 during periadolescence

This study evaluates the long-term effects of a six and 14-week morphine withdrawal in rats pretreated with a cannabinoid agonist (CP-55,940, CP) during periadolescence. Wistar rats (33 males; 32 females) were treated with CP or its vehicle (VH) from postnatal day (PND) 28-38. At PND100, rats performed morphine self-administration (MSA, 15d/12 h/session). Eight groups were defined according to pretreatment (CP), treatment (morphine), and sex. Three [¹⁸F]FDG-PET brain images were acquired: after MSA, and after six and 14 weeks of withdrawal. PET data were analyzed with SPM12. Endocannabinoid (EC) markers were evaluated in frozen brain tissue at endpoint. Females showed a higher mean number of self-injections than males. A main Sex effect on global brain metabolism was found. FDG uptake in males was discrete, whereas females showed greater brain metabolism changes mainly in areas of the limbic system after morphine treatment. Moreover, the morphine-induced metabolic pattern in females was exacerbated when CP was previously present. In addition, the CP-Saline male group showed reduced CB1R, MAGL expression, and NAPE/FAAH ratio compared to the control group, and morphine was able to reverse CB1R and MAGL expression almost to control levels. In conclusion, females showed greater and longer-lasting metabolic changes after morphine withdrawal than males, indicating a higher vulnerability and a different sensitivity to morphine in subjects pre-exposed to CP. In contrast, males primarily showed changes in EC markers. Together, our results suggest that CP pre-exposure contributes to the modulation of brain metabolism and EC systems in a sex-dependent manner.

First episode psychosis with and without the use of cannabis and synthetic cannabinoids: Psychopathology, global functioning and suicidal ideation and antipsychotic effectiveness

BACKGROUND

Natural Cannabis (NC) and Synthetic Cannabinoids (SCs) use can increase the risk of developing psychotic disorders and exacerbate their course.

AIMS

To examine the differences between psychoses not associated with cannabis use and those associated with NC and SCs use, evaluating psychotic symptoms, global functioning, dissociative symptoms and suicidal ideation.

METHODS

The sample of 61 patients with First Episode Psychosis (FEP) was divided into 3 groups: non-Cannabis users (non-users, N = 20); NC users (THC-users, N = 21); SCs users (SPICE-users, N = 20). Each group was assessed at FEP and after 3 and 9 months through specific psychopathological scales.

RESULTS

THC-users, and even more SPICE-users, displayed much more severe positive symptoms than non-users. Negative symptoms were higher among non-users. After 9 months the non-users had recovered significantly better than SPICE-users in their global functioning. Dissociative symptoms were significantly greater in substance users. Finally, suicidal ideation was higher in SPICE-users than in both THC-users and non-users.

DISCUSSION

The psychoses induced by NC and SCs showed different symptomatic pictures and outcomes from each other and when compared to the psychoses not associated with the use of substances; such knowledge could be relevant in identifying a specific drug treatment.

Cannabis in Adolescence: Lasting Cognitive Alterations and Underlying Mechanisms

Cannabis consumption during adolescence is an area of particular concern, owing to changes in the social and political perception of the drug, and presents a scientific, medical, and economic challenge. Major social and economic interests continue to push toward cannabis legalization as well as pharmaceutical development. As a result, shifting perceptions of both legal and illicit cannabis use across the population have changed the collective evaluation of the potential dangers of the product. The wave of cannabis legalization therefore comes with new responsibility to educate the public on potential risks and known dangers associated with both recreational and medical cannabis. Among these is the risk of long-term cognitive and psychological consequences, particularly following early-life initiation of use, compounded by high-potency and/or synthetic cannabis, and heavy/frequent use of the drug. Underlying these cognitive and psychiatric consequences are lasting aberrations in the development of synaptic function, often secondary to epigenetic changes. Additional factors such as genetic risk and environmental influences or nondrug toxic insults during development are also profound contributors to these long-term functional alterations following adolescent cannabis use. Preclinical studies indicate that exposure to cannabinoids during specific windows of vulnerability (e.g., adolescence) impacts neurodevelopmental processes and behavior by durably changing dendritic structure and synaptic functions, including those normally mediated by endogenous cannabinoids and neuronal circuits.

The Relationship Between Cannabis, Cognition, and Schizophrenia: It's Complicated

The consequences of cannabis use, especially in the context of schizophrenia, have gained increased importance with the legalization of cannabis in North America and across the globe. Cannabis use has multifaceted impacts on cognition in schizophrenia patients and healthy subjects. Healthy subjects, particularly those who initiated cannabis use at earlier ages and used high-potency cannabis for longer durations, exhibited poorer cognition mainly in working memory and attention. Cannabis use in schizophrenia has been associated with symptom exacerbation, longer and more frequent psychotic episodes, and poorer treatment outcomes. However, cannabis-using patients have better overall cognitive performance compared to patients who were not cannabis users. Interestingly, these effects were only apparent in lifetime cannabis users, but not in current (or within last 6 months) users. Moreover, higher frequency and earlier age of cannabis use initiation (i.e., before 17 years of age) were associated with better cognitive performance, although they had an earlier illness onset. Three possible hypotheses seem to come forward to explain this paradox. First, some components of cannabis may have antipsychotic or cognitive-enhancing properties. Secondly, chronic cannabis use may alter endocannabinoid signaling in the brain which could be a protective factor for developing psychosis or cognitive impairments. A third explanation could be their representation of a phenotypically distinct patient group with more intact cognitive functioning and less neurodevelopmental pathology. Multiple factors need to be considered to understand the complex relationship between cannabis, cognitive function, and schizophrenia. In short, age at initiation, duration and rate of cannabis use, abstinence duration, co-use of substances and alcohol, prescribed medications, relative cannabinoid composition and potency of cannabis, presence of genetic and environmental vulnerability factors are prominent contributors to the variability in outcomes. Animal studies support the disruptive effects of Δ9-tetrahydrocannabinol (THC) administration during adolescence on attention and memory performance. They provide insights about interaction of cannabinoid receptors with other neurotransmitter systems, such as GABA and glutamate, and other regulatory molecules, such as PSD95 and synaptophysin. Cannabidiol (CBD), on the other hand, can improve cognitive deficits seen in neurodevelopmental and chemically-induced animal models of schizophrenia. Future studies focusing on bridging the translational gaps between human and animal studies, through the use of translationally relevant methods of exposure (e.g., vaping), consistent behavioral assessments, and congruent circuit interrogations (e.g., imaging) will help to further clarify this complex picture.

Effects of cannabis regulation in Switzerland: Study protocol of a randomized controlled trial

Background

Cannabis is the most widely used illicit substance. Various countries have legalized cannabis for recreational use. Evidence on the health effects of cannabis regulation remains unclear and is mainly based on observational studies. To date, there is no randomized controlled study evaluating the impact of cannabis regulation for recreational use compared to the illicit market on relevant health indicators. The present study ("Weed Care") is the first to evaluate the impact of regulated cannabis access in pharmacies versus a waiting list control group representing the illicit market on problematic cannabis use as well as on mental and physical health.

Methods

The study is divided into two parts-a randomized controlled study of 6 months followed by an observational study of 2 years. Participants (N = 374) are randomly assigned to either the experimental group with access to legal cannabis in pharmacies or to the waiting list control group representing the current legal framework in Switzerland, namely the illicit market. After 6 months, all participants will have access to legal cannabis for the following 2 years (observational study). The primary outcome is problematic cannabis use as measured with the Cannabis Use Disorders Identification Test-Revised (CUDIT-R). Secondary outcomes are cannabis use patterns, mental disorders (e.g., depression, anxiety, and psychosis) and physical health (e.g., respiratory symptoms). Primary and secondary outcomes will be assessed online every 6 months. The study is approved by the responsible ethics committee as well as by the Swiss Federal Office of Public Health.

Discussion

Findings from this study may provide a scientific basis for future discussions about addiction medicine and cannabis policy in Switzerland.

Clinical Trial Registration

ClinicalTrials.gov (NCT05522205). https://clinicaltrials.gov/ct2/show/NCT05522205.

Delta-8-THC association with psychosis: A case report with literature review

BACKGROUND

Cannabis (Δ⁹-THC) is the most commonly consumed illicit drug. The Agricultural Improvement Act of 2018 removed hemp, a strain of Cannabis sativa, as a controlled substance. This law allowed the plant to be processed into its components, which contain <0.3% Δ⁹-THC. As a result, delta-8-tetrahydrocannabinol (Δ⁸-THC), a federally unregulated substance, grew in popularity in 2020. Δ⁸-THC is readily available in most gas stations or head shops and may be considered harmless by patients. However, an increasing number of patients admitted for psychiatric hospitalization report use, with limited literature on the effects.

CASE PRESENTATIONS

This case report describes three individual cases of patients who required admission to a university psychiatric hospital after the regular use solely of Δ⁸-THC. All three patients developed psychotic and paranoid symptoms concurrently with the use of Δ⁸-THC, with a severity exceeding their previous historical presentations. The presenting psychotic symptoms were also atypical for all three patients. New-onset violence and visual hallucinations were noted in two of the patients, one patient with no previous psychiatric history and one patient while on a therapeutic dose of his antipsychotic. In the third case, a new onset of bizarre, fixed delusions of puppies dissolving in the bathtub developed.

CONCLUSION

This report adds to the limited body of evidence on Δ⁸-THC documenting a temporal association between Δ⁸-THC use and the development of psychotic symptoms. A strong body of research already correlates the continued use of Δ⁹-THC with psychosis, and Δ⁸-THC acts at the same CB₁ and CB₂ receptors as Δ⁹-THC. Therefore, it is hypothesized that Δ⁸-THC may have similar adverse psychiatric effects as Δ⁹-THC. These conclusions are not without speculation, due to the need for self or collateral-reporting of Δ⁸-THC use as urine drug screening cannot distinguish Δ⁸-THC from Δ⁹-THC, and the patients' symptoms could be explained by medication non-adherence and primary psychotic disorders. However, physicians should be encouraged to gather a specific history of Δ⁸-THC use and treat patients with Δ⁸-THC-related intoxication and symptoms.

Epidemiology of Untreated Psychoses in 3 Diverse Settings in the Global South: The International Research Program on Psychotic Disorders in Diverse Settings (INTREPID II)

Importance

Less than 10% of research on psychotic disorders has been conducted in settings in the Global South, which refers broadly to the regions of Latin America, Asia, Africa, and Oceania. There is a lack of basic epidemiological data on the distribution of and risks for psychoses that can inform the development of services in many parts of the world.

Objective

To compare demographic and clinical profiles of cohorts of cases and rates of untreated psychoses (proxy for incidence) across and within 3 economically and socially diverse settings in the Global South. Two hypotheses were tested: (1) demographic and clinical profiles of cases with an untreated psychotic disorder vary across setting and (2) rates of untreated psychotic disorders vary across and within setting by clinical and demographic group.

Design, Setting, and Participants

The International Research Program on Psychotic Disorders in Diverse Settings (INTREPID II) comprises incidence, case-control, and cohort studies of untreated psychoses in catchment areas in 3 countries in the Global South: Kancheepuram District, India; Ibadan, Nigeria; and northern Trinidad. Participants were individuals with an untreated psychotic disorder. This incidence study was conducted from May 1, 2018, to July 31, 2020. In each setting, comprehensive systems were implemented to identify and assess all individuals with an untreated psychosis during a 2-year period. Data were analyzed from January 1 to May 1, 2022.

Main Outcomes and Measures

The presence of an untreated psychotic disorder, assessed using the Schedules for Clinical Assessment in Neuropsychiatry, which incorporate the Present State Examination.

Results

Identified were a total of 1038 cases, including 64 through leakage studies (Kancheepuram: 268; median [IQR] age, 42 [33-50] years; 154 women [57.5%]; 114 men [42.5%]; Ibadan: 196; median [IQR] age, 34 [26-41] years; 93 women [47.4%]; 103 men [52.6%]; Trinidad: 574; median [IQR] age, 30 [23-40] years; 235 women [40.9%]; 339 men [59.1%]). Marked variations were found across and within settings in the sex, age, and clinical profiles of cases (eg, lower percentage of men, older age at onset, longer duration of psychosis, and lower percentage of affective psychosis in Kancheepuram compared with Ibadan and Trinidad) and in rates of untreated psychosis. Age- and sex-standardized rates of untreated psychoses were approximately 3 times higher in Trinidad (59.1/100 000 person-years; 95% CI, 54.2-64.0) compared with Kancheepuram (20.7/100 000 person-years; 95% CI, 18.2-23.2) and Ibadan (14.4/100 000 person-years; 95% CI, 12.3-16.5). In Trinidad, rates were approximately 2 times higher in the African Trinidadian population (85.4/100 000 person-years; 95% CI, 76.0-94.9) compared with the Indian Trinidadian (43.9/100 000 person-years; 95% CI, 35.7-52.2) and mixed populations (50.7/100 000 person-years; 95% CI, 42.0-59.5).

Conclusions and Relevance

This analysis adds to research that suggests that core aspects of psychosis vary by historic, economic, and social context, with far-reaching implications for understanding and treatment of psychoses globally.

Cannabis Practices Among a Gender-Diverse Sample of Young Adults

Background

Gender is an important factor in understanding cannabis patterns, yet few studies have explored cannabis patterns among gender minority (GM) individuals - particularly among high-risk age groups including young adults. The evolving cannabis market is reshaping typical patterns of cannabis use in the U.S. The combination of these factors warrants increased efforts to examine cannabis practices in gender-diverse samples.

Methods

Online survey participants between 18-34 years (N=2377) from the U.S. provided information on cannabis practices from May - July 2021. Gender differences across several cannabis outcomes (onset, methods of consumption, product potency, frequency, and quantity) were assessed. Bivariate tests and multiple regression models examined associations between gender (cisgender men: n=1020; cisgender women: n=1178; and GM: n=179) and cannabis outcomes adjusting for sociodemographic characteristics.

Results

In regression models adjusted for sociodemographic characteristics, GM identity was associated with later age of onset and lower likelihood of daily use compared to cisgender men and women. Identifying as GM or cisgender woman was associated with fewer lifetime methods of consumption and lower plant and concentrate potency usage.

Conclusions

Findings provide initial insights into potential gender differences in cannabis practices from a sample of heavy cannabis users. GM young adults report use patterns indicative of lower risk compared to cisgender men and women in our sample. Future investigations of gender differences in cannabis use that explore specific gender minority categories and that include alternative sampling strategies are needed to better understand differential risks associated with gender.

Cognitive functioning and cannabis use in first-episode psychosis

AIM

Cannabis use is common in people with psychotic disorders. However, the effect of cannabis on cognition in psychosis remains unclear. Our study investigates relationships between the history of cannabis use and cognitive performance in patients with first-episode psychosis (FEP) during a one-year follow-up.

METHODS

The present study included FEP (N = 91) and control (N = 61) groups. Cannabis use was evaluated with a self-report questionnaire, clinical assessment, and medical records during a lifetime and 12 months prior to the treatment onset (recent). Symptoms of psychosis and anxiety were evaluated on the brief psychiatric rating scale. Negative symptoms were assessed using the scale for the assessment of negative symptoms. Cognitive tests were used to evaluate neurocognition (summarized in the g factor) and social cognition. Crude regression analyses for the g factor included variables of cannabis use as independent variables. Full regression models were controlled for gender, education, and clinical symptoms.

RESULTS

In the FEP group, men used cannabis more frequently than women. In the crude regression model for FEP patients, never having used cannabis was associated with a better neurocognitive profile at 12 months. In the full model, more severe anxiety symptoms were associated with better neurocognition at two months, and less severe negative symptoms were associated with better neurocognition at 12 months. Cannabis use was not associated with social cognition. No associations between cognitive performance and cannabis use emerged in the controls.

CONCLUSION

Negative and affective symptom severity in FEP was associated with cognitive performance to a greater degree than a lifetime history of cannabis use.

Development and initial validation of a reliable German self-report measure to assess acute cannabis intoxication-effects (CanTox-17)

OBJECTIVES

Both positive and negative including psychotic-like cannabis intoxication effects are well-established. Yet, consequences for consumption patterns, addictive behavior or psychotic developments are poorly researched in general, in Germany not at all. Thus, objective was to develop the first German-language questionnaire operationalizing acute cannabis intoxication effects, based on the original "Cannabis Experience Questionnaire" (CEQ).

METHODS

After expert translation of the CEQ, items related to acute intoxication effects were presented to a sample of 537 cannabis users. Four- and five-factorial solutions of explorative factor analysis with a randomly split sub-sample 1 were cross-validated by confirmatory factor analysis on sub-sample 2.

RESULTS

After content review of factors and analysis of external validity, a 17 item four-factorial model was approved. Factors are (1) "paranoia/dysphoria", (2) "confusion/disorientation", (3) "euphoria/creativity", (4) "psychosis-like/loss of reality". Model fit is satisfactory (RMSEA = 0.058, SRMR = 0.065, CFI = 0.929, TLI = 0.914). Correlations with corresponding external measures support construct validity.

CONCLUSIONS

The present questionnaire is a time-efficient, valid and reliable instrument. Thus, predictors of different cannabis intoxication effects can be analysed for the first time in German-speaking area, as well as their significance for substance use or psychosis risk.

Cannabis smoking increases the risk of suicide ideation and suicide attempt in young individuals of 11-21 years: A systematic review and meta-analysis

BACKGROUND

Cannabis is the most frequently consumed drug around the world. Its use has been associated with increased suicide behaviors; nonetheless, the association of cannabis smoking and suicide behaviors in adolescents has not yet been established. The aim of this systematic review and meta-analysis was to evaluate the risk of suicide attempt, suicidal ideation or suicide planning in individuals of 11-21 years of age who smoke cannabis.

METHODS

We performed an online searched using PubMed, EBSCO and Science Direct databases, up to July 2021. We calculated odds ratio with 95% confidence intervals to evaluate the association between suicide attempt, suicidal ideation or suicide planning and cannabis smoking in individuals of 11-21 years of age.

RESULTS

Twenty studies reported suicide attempts in 34,859 young individuals, suicidal ideation in 26, 937 individuals, and suicide planning in 9054 young individuals. We found an increased risk of suicide attempt in cannabis smokers than in non-cannabis users (OR: 2.33; 95% CI: 1.78-3.05; Z p value; <0.0001; I² = 97.12%), as well as a significant association between cannabis smoking and suicidal ideation (OR: 2.04; 95%CI: 1.64-2.53; Z p value: <0.001; I²: 94.88) and suicide planning (OR: 1.674; 95% CI: 1.554-1.804; Z p value: 0.000; I²: 92.609). Subgroup analyses showed that American teens have an increased risk of suicidal ideation; the meta-regression analysis revealed that age was negatively associated with the risk of suicide attempt.

CONCLUSIONS

This meta-analysis shows that cannabis smoking increased the risk of suicide attempt, suicidal ideation and suicide planning in young individuals of 11-21 years of age. The high risk of suicide behaviors could vary depending on the population studied; therefore, more studies are necessary to corroborate the risk of presenting suicide behaviors in individuals of 11-21 years of age who smoke cannabis.

Association of Polymorphism within the Putative miRNA Target Site in the 3'UTR Region of the DRD2 Gene with Neuroticism in Patients with Substance Use Disorder

The study aims at looking into associations between the polymorphism rs6276 that occurs in the putative miRNA target site in the 3'UTR region of the DRD2 gene in patients with substance use disorder (SUD) comorbid with a maniacal syndrome (SUD MANIA). In our study, we did not state any essential difference in DRD2 rs6276 genotype frequencies in the studied samples of SUD MANIA, SUD, and control subjects. A significant result was found for the SUD MANIA group vs. SUD vs. controls on the Neuroticism Scale of NEO FFI test, and DRD2 rs6276 (p = 0.0320) accounted for 1.7% of the variance. The G/G homozygous variants were linked with lower results on the neuroticism scale in the SUD MANIA group because G/G alleles may serve a protective role in the expression of neuroticism in patients with SUD MANIA. So far, there have been no data in the literature on the relationship between the miRSNP rs6276 region in the DRD2 gene and neuroticism (personal traits) in patients with a diagnosis of substance use disorder comorbid with the affective, maniacal type disturbances related to SUD. This is the first report on this topic.

Trajectories of adolescent psychotic-like experiences and early cannabis exposure: Results from a Finnish Birth Cohort Study

BACKGROUND

Longitudinal studies examining the effect of cannabis exposure (CE) on the prognosis of adolescents with psychotic-like experiences (PLEs) are scarce. We examined trajectories of mental health in adolescents with PLEs and cannabis exposure.

METHODS

The Northern Finland Birth Cohort 1986 (n = 6552) with linkage to nationwide register data was used. Information on lifetime cannabis exposure was collected when participants were aged 15/16. Register-based outcome data on diagnoses made in clinical practice were obtained until age 33. Logistic regression was used to study the association of PLE/CE patterns and subsequent psychiatric disorders. The group with neither PLEs nor CE was utilized as the reference group. Parental psychiatric disorders, family structure, sex, frequent alcohol intoxications, daily smoking and illicit substance use other than cannabis were adjusted for.

RESULTS

In all, 6552 subjects (49.2 % males) were included in analysis. PLEs with cannabis exposure were associated with any psychiatric disorder (OR = 2.59; 95 % CI 1.82-3.68), psychotic disorders (OR = 3.86; 95 % CI 1.83-8.11), mood disorders (OR 4.07; 95 % CI 2.74-6.04), depressive disorders (OR = 4.35; 95 % CI 2.93-6.48), anxiety disorders (OR = 2.06; 95 % CI 1.34-3.17) and substance use disorders (OR = 2.26; 95 % CI 1.13-4.50) compared to reference group. Effect sizes were greater for group with both PLEs and cannabis use than for group with PLEs only.

CONCLUSIONS

Early-onset cannabis use is an adverse prognostic marker for adolescents with PLEs after extensive confounder control including other substance use.

Psychosocial markers of age at onset in bipolar disorder: a machine learning approach

BACKGROUND

Bipolar disorder is a chronic and severe mental health disorder. Early stratification of individuals into subgroups based on age at onset (AAO) has the potential to inform diagnosis and early intervention. Yet, the psychosocial predictors associated with AAO are unknown.

AIMS

We aim to identify psychosocial factors associated with bipolar disorder AAO.

METHOD

Using data from the Bipolar Disorder Research Network UK, we employed least absolute shrinkage and selection operator regression to identify psychosocial factors associated with bipolar disorder AAO. Twenty-eight factors were entered into our model, with AAO as our outcome measure.

RESULTS

We included 1022 participants with bipolar disorder (μ = 23.0, s.d. ± 9.86) in our model. Six variables predicted an earlier AAO: childhood abuse (β = -0.2855), regular cannabis use in the year before onset (β = -0.2765), death of a close family friend or relative in the 6 months before onset (β = -0.2435), family history of suicide (β = -0.1385), schizotypal personality traits (β = -0.1055) and irritable temperament (β = -0.0685). Five predicted a later AAO: the average number of alcohol units consumed per week in the year before onset (β = 0.1385); birth of a child in the 6 months before onset (β = 0.2755); death of parent, partner, child or sibling in the 6 months before onset (β = 0.3125); seeking work without success for 1 month or more in the 6 months before onset (β = 0.3505) and a major financial crisis in the 6 months before onset (β = 0.4575).

CONCLUSIONS

The identified predictor variables have the potential to help stratify high-risk individuals into likely AAO groups, to inform treatment provision and early intervention.

Can epigenetics shine a light on the biological pathways underlying major mental disorders?

A significant proportion of the global burden of disease can be attributed to mental illness. Despite important advances in identifying risk factors for mental health conditions, the biological processing underlying causal pathways to disease onset remain poorly understood. This represents a limitation to implement effective prevention and the development of novel pharmacological treatments. Epigenetic mechanisms have emerged as mediators of environmental and genetic risk factors which might play a role in disease onset, including childhood adversity (CA) and cannabis use (CU). Particularly, human research exploring DNA methylation has provided new and promising insights into the role of biological pathways implicated in the aetio-pathogenesis of psychiatric conditions, including: monoaminergic (Serotonin and Dopamine), GABAergic, glutamatergic, neurogenesis, inflammatory and immune response and oxidative stress. While these epigenetic changes have been often studied as disease-specific, similarly to the investigation of environmental risk factors, they are often transdiagnostic. Therefore, we aim to review the existing literature on DNA methylation from human studies of psychiatric diseases (i) to identify epigenetic modifications mapping onto biological pathways either transdiagnostically or specifically related to psychiatric diseases such as Eating Disorders, Post-traumatic Stress Disorder, Bipolar and Psychotic Disorder, Depression, Autism Spectrum Disorder and Anxiety Disorder, and (ii) to investigate a convergence between some of these epigenetic modifications and the exposure to known risk factors for psychiatric disorders such as CA and CU, as well as to other epigenetic confounders in psychiatry research.

A network approach to relationships between cannabis use characteristics and psychopathology in the general population

Cannabis use characteristics, such as earlier initiation and frequent use, have been associated with an increased risk for developing psychotic experiences and psychotic disorders. However, little is known how these characteristics relate to specific aspects of sub-clinical psychopathology in the general population. Here, we explore the relationships between cannabis use characteristics and psychopathology in a large general population sample (N = 2,544, mean age 29.2 years, 47% women) by employing a network approach. This allows for the identification of unique associations between two cannabis use characteristics (lifetime cumulative frequency of cannabis use, age of cannabis use initiation), and specific psychotic experiences and affective symptoms, while controlling for early risk factors (childhood trauma, urban upbringing). We found particularly pronounced unique positive associations between frequency of cannabis use and specific delusional experiences (persecutory delusions and thought broadcasting). Age of cannabis use initiation was negatively related to visual hallucinatory experiences and irritability, implying that these experiences become more likely the earlier use is initiated. Earlier initiation, but not lifetime frequency of cannabis use, was related to early risk factors. These findings suggest that cannabis use characteristics may contribute differentially to risk for specific psychotic experiences and affective symptoms in the general population.

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.

Public Health Implications of Cannabis Legalization: An Exploration of Adolescent Use and Evidence-Based Interventions

This article examines the relaxation of state marijuana laws, changes in adolescent use of marijuana, and implications for drug education. Under federal law, use of marijuana remains illegal. In spite of this federal legislation, as of 1 June 2021, 36 states, four territories and the District of Columbia have enacted medical marijuana laws. There are 17 states, two territories and the District of Columbia that have also passed recreational marijuana laws. One of the concerns regarding the enactment of legislation that has increased access to marijuana is the possibility of increased adolescent use of marijuana. While there are documented benefits of marijuana use for certain medical conditions, we know that marijuana use by young people can interfere with brain development, so increased marijuana use by adolescents raises legitimate health concerns. A review of results from national survey data, including CDC’s YRBS, Monitoring the Future, and the National Household Survey on Drug Use, allows us to document changes in marijuana use over time. Increased legal access to marijuana also has implications for educational programming. A “Reefer Madness” type educational approach no longer works (if it ever did). We explore various strategies, including prevention programs for education about marijuana, and make recommendations for health educators.

The Efficacy of Cannabis in Reducing Back Pain: A Systematic Review

OBJECTIVE

To critically analyze the evidence and efficacy of cannabis to treat surgical and nonsurgical back pain via a Systematic Review.

METHODS

We conducted a systematic review to investigate the efficacy of cannabis to treat non-surgical and surgical back pain. A literature search was performed with MEDLINE and Embase databases. Only RCTs and prospective cohort studies with concurrent control were included in this study. Risk of bias and quality grading was assessed for each included study.

RESULTS

Database searches returned 1738 non-duplicated results. An initial screening excluded 1716 results. Twenty-two full text articles were assessed for eligibility. Four articles ultimately met pre-determined eligibility and were included in the study. Two studies addressed post-SCI pain while other two studies addressed low back pain. No studies specifically examined the use of cannabis for surgical back pain. The type of cannabis varied between study and included THC, dronabinol, and Nabilone. A total of 110 patients were included in the four studies reviewed. In each study, there was a quantifiable advantage of cannabis therapy for alleviating back pain. There were no serious adverse effects reported.

CONCLUSIONS

In all articles, cannabis was shown to be effective to treat back pain with an acceptable side effect profile. However, long-term follow up is lacking. As medicinal cannabis is being used more commonly for analgesic effect and patients are "self-prescribing" cannabis for back pain, additional studies are needed for healthcare providers to confidently recommend cannabis therapy for back pain.

STUDY DESIGN

Systematic review.

Association of Cannabis Use-Related Predictor Variables and Self-Reported Psychotic Disorders: U.S. Adults, 2001-2002 and 2012-2013

OBJECTIVE

The authors sought to determine the association of cannabis indicators with self-reported psychotic disorders in the U.S. general population.

METHODS

Participants were from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; 2001-2002; N=43,093) and NESARC-III (2012-2013; N=36,309). Logistic regression was used to estimate standardized prevalences of past-year self-reported psychotic disorders within each survey and to evaluate the association of past-year self-reported psychotic disorders with indicators of nonmedical cannabis use (any use; frequent use [at least three times/week], daily/near-daily use, and DSM-IV cannabis use disorder) compared with those with no past-year nonmedical cannabis use. Whether the strength of associations differed between surveys was indicated by difference-in-difference tests (between-survey contrasts) and ratios of odds ratios between surveys.

RESULTS

Self-reported psychotic disorders were significantly more prevalent among participants with any nonmedical cannabis use than those without (2001-2002: 1.65% compared with 0.27%; 2012-2013: 1.89% compared with 0.68%). In 2001-2002, self-reported psychotic disorders were unrelated to either frequent use or daily/near-daily use. However, in 2012 - 2013, compared with nonusers, self-reported psychotic disorders were more common among participants with frequent use and those with daily/near-daily nonmedical cannabis use (2012-2013: 2.79% and 2.52%, respectively, compared with 0.68% among nonusers). Self-reported psychotic disorders were significantly more prevalent among participants with cannabis use disorder than nonusers in both surveys (2001-2002: 2.55% compared with 0.27%; 2012 - 2013: 3.38% compared with 0.68%). The strength of these associations did not change over time.

CONCLUSIONS

Data from the U.S. general population, especially more recent data, suggest associations between self-reported psychotic disorder and frequent nonmedical cannabis use and cannabis use disorder. Clinicians and policy makers should consider these relationships when monitoring patients and formulating programs.

Cannabis use disorder and dissociation: A report from a prospective first-episode psychosis study

BACKGROUND

Cannabis is the most used recreational drug worldwide. Its use can increase the risk of developing psychotic disorders and exacerbate their course. However, the relationship between cannabis use and dissociative symptoms has been scarcely investigated.

AIMS

To examine differences in psychotic and dissociative symptoms, and in functioning in first-episode psychotic patients (FEPp) using cannabis compared with those not using cannabis.

METHODS

Between January 2014 and December 2019, seventy FEPp with cannabis use disorder (N = 35) and without it (N = 35) were recruited in psychiatric inpatient facilities in the Italian regions of Lazio and Piemonte. All subjects were assessed at FEP, after 4 and 8 months, using the Positive and Negative Syndrome Scale (PANSS), the Global Assessment of Functioning (GAF) scale and the Dissociative Experiences Scale - II (DES-II). Detailed information on the pattern of cannabis and other substance use were collected.

RESULTS

FEP using cannabis showed higher levels of positive symptomatology, dissociative experiences and worse functioning than their non-user counterpart, despite a comparable antipsychotic treatment. At an eight-month prospective evaluation, FEP using cannabis still showed higher levels of positive symptomatology and dissociation. Moreover, global functioning worsened over time in FEPp using cannabis, whereas it improved those not using it.

DISCUSSION

Our findings suggest that a greater degree of dissociation and positive symptoms at FEPp and their persistence over time may characterise cannabis-associated psychosis. Both these factors might explain the overall functioning worsening over time that we observed in the cannabis-user group compared to the functioning improvement in the non-user group.

Duration of Untreated Disorder and Cannabis Use: An Observational Study on a Cohort of Young Italian Patients Experiencing Psychotic Experiences and Dissociative Symptoms

BACKGROUND

The Duration of Untreated Psychosis (DUP) is the time between the first-episode psychosis (FEP) and the initiation of antipsychotic treatment. It is an important predictor of several disease-related outcomes in psychotic disorders. The aim of this manuscript is investigating the influence of cannabis on the DUP and its clinical correlates.

METHODS

During years 2014-2019, sixty-two FEP patients with and without cannabis use disorder (CUD) were recruited from several Italian psychiatric hospitals. The subjects were then divided into two groups based on the duration of the DUP and assessed at the beginning of the antipsychotic treatment and after 3 and 6 months, using the Positive and Negative Syndrome Scale (PANSS), the Global Assessment of Functioning (GAF) scale, and the Dissociative Experiences Scale (DES-II).

RESULTS

As expected, a longer DUP was associated with worse symptoms and cannabis use did not seem to affect the DUP, but both were related with more dissociative symptoms at onset and over time.

DISCUSSION

According to our study, cannabis use can be a predictor of FEP and DUP, and of disease outcome. However, several factors might influence the relationship between cannabis use and DUP. Preventing cannabis use and early diagnosis of psychotic disorders might impact the disease by reducing the persistence of symptoms and limiting dissociative experiences.