Associations between adolescent cannabis use and brain structure in psychosis

Cannabis and Psychosis

Psychosis and cannabis use may overlap in multiple ways in young people. Research suggests that cannabis use increases risk for having psychotic symptoms, both attenuated (subthreshold) and acute. Cannabis use may also exacerbate psychosis symptoms among young people with underlying psychosis risk and psychotic disorders. Although there are suggestions for treating co-occurring psychosis and cannabis use in young people (e.g., incorporating cannabis use assessment and treatment strategies into specialized early psychosis care), there are many gaps in clinical trial research to support evidence-based treatment of these overlapping concerns.

Spanish versions and validation of a series of rating scales and visual analogue scales to assess the subjective effects of cannabis

Cannabis is being legalized for medical and recreational purposes all around the world. However, the understanding of the psychological effects of cannabis is still limited, and it has been previously linked to mental disorders such as schizophrenia. Lately, new scales have been created and adapted to measure its psychological effects. The aim of this study is to create Spanish versions of some of these scales and test their psychometric characteristics. One hundred sixteen participants were recruited from Cannabis Social Clubs (CSC) in Barcelona, Spain. Participants under the effects of their own cannabis completed the Cannabis Experience Questionnaire-modified version (CEQ-mv), Addiction Research Centre Inventory-18 (ARCI-18), Psychotomimetic States Inventory (PSI) and Visual Analogue Scales (VAS). Questionnaires were completed in the CSC, providing a naturalistic setting for the study. Exploratory factor analysis and internal consistency were analyzed. PSI was reduced from a 6-factor to a 4-factor model with adequate to low reliability, ARCI-18 was reduced from a 3-factor to a 2-factor model with good reliability, and VAS were reduced from a 4-factor to a 3-factor model, also with good reliability. These questionnaires showed adequate reliability and can be used in future studies to test the subjective effects of cannabis in clinical and naturalistic settings.

Prenatal risk factors and postnatal cannabis exposure: Assessing dual models of schizophrenia-like rodents

Schizophrenia (SCZ) is a multifactorial neurodevelopmental disorder caused by genetic and environmental alterations, especially during prenatal stages. On the other hand, cannabis consumption in adolescence has been also linked to an increased risk of developing SCZ. The combination of both hits has been proposed as the dual hit hypothesis of SCZ. We systematically reviewed prenatal environmental alterations and cannabis consumption during adolescence that are associated with an increased risk of SCZ, following the PRISMA model. The analysis focused on dual animal models where the first hit is prenatal environmental exposure and the second hit consists of postnatal cannabis exposure. The articles were evaluated by three independent reviewers based on inclusion criteria. We extracted the first author´s name, year, model species, sex and analysis. The articles reported on dual murine models and their effects on weight, behavior, genetics, electrophysiology and brain structure and function. We conclude that the defects caused by the dual hits depend on the sex of the model, as well as type of hits.

Cannabis and Psychosis

Psychosis and cannabis use may overlap in multiple ways in young people. Research suggests that cannabis use increases risk for having psychotic symptoms, both attenuated (subthreshold) and acute. Cannabis use may also exacerbate psychosis symptoms among young people with underlying psychosis risk and psychotic disorders. Although there are suggestions for treating co-occurring psychosis and cannabis use in young people (e.g., incorporating cannabis use assessment and treatment strategies into specialized early psychosis care), there are many gaps in clinical trial research to support evidence-based treatment of these overlapping concerns.

Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis

OBJECTIVES

The liberalisation of cannabis laws, the increasing availability and potency of cannabis has renewed concern about the risk of psychosis with cannabis.

METHODS

The objective of the WFSBP task force was to review the literature about this relationship.

RESULTS

Converging lines of evidence suggest that exposure to cannabis increases the risk for psychoses ranging from transient psychotic states to chronic recurrent psychosis. The greater the dose, and the earlier the age of exposure, the greater the risk. For some psychosis outcomes, the evidence supports some of the criteria of causality. However, alternate explanations including reverse causality and confounders cannot be conclusively excluded. Furthermore, cannabis is neither necessary nor sufficient to cause psychosis. More likely it is one of the multiple causal components. In those with established psychosis, cannabis has a negative impact on the course and expression of the illness. Emerging evidence also suggests alterations in the endocannabinoid system in psychotic disorders.

CONCLUSIONS

Given that exposure to cannabis and cannabinoids is modifiable, delaying or eliminating exposure to cannabis or cannabinoids, could potentially impact the rates of psychosis related to cannabis, especially in those who are at high risk for developing the disorder.

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.

The relationship between cannabis use and cognition in people with bipolar disorder: A systematic scoping review

Bipolar disorder (BD) and cannabis use are highly comorbid and are each associated with cognitive impairment.  Given the prevalence of cannabis use in people with BD, it is important to understand whether the two interact to impact cognitive function. We performed a systematic scoping review to determine what is currently known in this field. We systematically searched PubMed, Embase, CINAHL, Web of Science, and PsycINFO for studies on the relationship between cannabis use and cognition in people with BD or relevant animal models. Six observational human studies and no animal studies met inclusion criteria. Two studies found cannabis use in BD was associated with better performance in some cognitive domains, while three studies found no association. One study found cannabis use in BD was associated with worse overall cognition. Overall, most identified studies suggest cannabis use is not associated with significant cognitive impairment in BD; however, the scope of knowledge in this field is limited, and more systematic studies are clearly required. Future studies should focus on longitudinal and experimental trials, and well-controlled observational studies with rigorous quantification of the onset, frequency, quantity, duration, and type of cannabis use, as well as BD illness features.

Adverse Effects of Recreational and Medical Cannabis

PURPOSE OF REVIEW

This comprehensive review discusses the adverse effects known today about marijuana, for either medical or recreational use. It reviews the role of cannabis in the treatment of chronic pain, cognitive and neurological adverse effects, special cases and addiction.

RECENT FINDINGS

Cannabinoids work through the endocannabinoids system and inhibit the release of GABA and glutamate in the brain, impact neuromodulation, as well as dopamine, acetylcholine and norepinephrine release. They affect reward, learning and pain. The use of cannabis is increasing nationally and world-wide for both recreational and medicinal purposes, however, there is relatively only low quality evidence to the efficacy and adverse effects of this. Cannabis and its derivatives may be used for treatment of chronic pain. They are via CB1 receptors that are thought to modulate nociceptive signals in the brain. CB2 receptors in the DRG likely affect pain integration in the afferent pathways, and peripherally CB2 also affects noradrenergic pathways influencing pain. A large proportion of users may see more than 50% of chronic pain alleviation compared with placebo. Cannabis affects cognition, most notably executive function, memory and attention, and may deteriorate the boundary between emotional and executive processing. Cannabis impairs memory in the short run, which become more significant with chronic use, and may also be accompanied by poorer effort, slower processing and impacted attention. It is generally believed that long-term use and earlier age are risk factor for neurocognitive deficits; neuroimaging studies have shown reduced hippocampal volume and density. Executive functions and memory are worse in adolescent users versus adults. Cannabis addiction is different and likely less common than other addictive substances, but up to 10% of users meet criteria for lifetime cannabis dependence. Addiction patterns may be linked to genetic and epigenetic differences. It is still unclear whether abstinence reverses patterns of addiction, and more research is required into this topic.

SUMMARY

Cannabis use has become more abundant for both medical and recreational use. It carries likely benefits in the form of analgesia, anti-emesis and improved appetite in chronic patients. The evidence reviewing adverse effects of this use are still limited, however, exiting data points to a clear link with neurocognitive deterioration, backed by loss of brain volume and density. Addiction is likely complex and variable, and no good data exists to support treatment at this point. It is becoming clear that use in earlier ages carries a higher risk for long-term deficits. As with any other drug, these risks should be considered alongside benefits prior to a decision on cannabis use.

Adolescent Substance Abuse, Transgenerational Consequences and Epigenetics

Adolescence is the transitional period between childhood and adulthood and a critical period in brain development. Adolescence in humans is also associated with increased expression of risk-taking behaviors. Epidemiological and clinical studies, for example, show a surge of drug abuse and raise the hypothesis that the adolescent brain undergoes critical changes resulting in diminished control. Determining how substance abuse during this critical period might cause longterm neurobiological changes in cognition and behavior is therefore critically important. The present work aims to provide an evaluation of the transgenerational and multi-generational phenotypes derived from parent animals exposed to drugs of abuse only during their adolescence. Specifically, we will consider changes found following the administration of cannabinoids, nicotine, alcohol and opiates. In addition, epigenetic modifications of the genome following drug exposure will be discussed as emerging evidence of the underlying adverse transgenerational effects. Notwithstanding, much of the new data discussed here is from animal models, indicating that future clinical studies are much needed to better understand the neurobiological consequences and mechanisms of drug actions on the human brains' development and maturation.

The Future of Substance Abuse Now: Relationships among Adolescent Use of Vaping Devices, Marijuana, and Synthetic Cannabinoids

Background: Substances that can be vaped include nicotine, marijuana, cocaine, heroin, and a range of synthetic drugs called new psychoactive substances (NPS). Due to the rising popularity of vaping among adolescents, it is crucial to understand the relationships between vaping and illicit drug use. Objectives: This paper examined the prevalence and trends of using vaping devices, marijuana vaping, marijuana products, synthetic cannabinoids and mist contents among youth. Methods: The study utilized 5 sets of public cross-sectional national data from the "Monitoring the Future" surveys during 2014-2018. It employed logistic regression to analyze the data. Results: There was an increase from 10.5% in 2017 to 20.8% in 2018 for the past 30-day use of vaping devices among 12^th graders. Furthermore, there was an increase from 21.6% in 2017 to 34.5% in 2018 for the past 12-month use of marijuana via vaping device among 12^th-grade marijuana users. Additionally, there were significant associations between vaping device use and marijuana vaping, between vaping device use and marijuana use, between vaping device use and synthetic cannabinoids use, and between marijuana use and synthetic cannabinoids use from 2016 to 2018. Conclusions: Vaping emerged as another major route of marijuana administration among youth. Adolescent marijuana users had higher odds of using synthetic cannabinoids. This finding highlighted the importance of understanding what adolescent substance consumption pattern would be where marijuana was legalized. It also supported the hypothesis that vaping devices use correlates with, or is associated with, marijuana and synthetic cannabinoids use.

The Association Between Cannabis Use and Schizophrenia: Causative or Curative? A Systematic Review

Marijuana is one of the most abused substances in the world. Marijuana is getting legalized around the world. So, it is crucial to understand its effect on our mental health. Its impact on the schizophrenia spectrum needs our special attention. Even though marijuana has been around for a long time, its exact effects are still unknown. Schizophrenia is a chronic illness affecting approximately 20 million people worldwide. Schizophrenia and cannabis seem to have a close relationship, and we want to explore this. We want to know if marijuana is causing, exacerbating, or treating schizophrenia. This systematic review explores this question. We searched online resources like PubMed, PubMed Central, Cochrane Library, and Google Scholar for systematic reviews, traditional reviews, randomized controlled trials, and meta-analysis on cannabis and schizophrenia/ psychosis. We included human studies published in peer-reviewed journals in the English language in the last five years. After reviewing 96 initial results of our search, we excluded 25 duplicates, 29 abstracts, and 18 irrelevant articles. We did a quality assessment for the remaining 24 studies using various quality assessment tools. After the quality assessment, we found 12 articles were of low quality and excluded those. We included the remaining 12 final studies in our systematic review. Out of these 12 studies, five were traditional reviews, two systematic reviews, two meta-analysis, and three observational studies. Six of the articles were on cannabis’s effect on just schizophrenia or psychotic disorder. The other six included schizophrenia plus other psychiatric or neurological illnesses. Ten of the studies had data supporting the causative link between cannabis and schizophrenia. Eight records had data supporting the exacerbating effect of marijuana. Six studies had data supporting the therapeutic effect of the cannabidiol (CBD) component of cannabis. From the current data, we can conclude that the tetrahydrocannabinol (THC) component of cannabis can be the main culprit causing psychosis and schizophrenia in the at-risk population. THC can also be the one exacerbating symptoms and causing an adverse prognosis in already diagnosed patients. Even though CBD shows therapeutic effects and THC opposing effects, the data is minimal and low safety and efficacy warrants more research. The relation between cannabis and schizophrenia needs further investigation. We need more case-control studies and clinical trials with a larger population to get conclusive data.

The psychosis risk timeline: can we improve our preventive strategies? Part 2: adolescence and adulthood

Current understanding of psychosis development is relevant to patients' clinical outcomes in mental health services as a whole, given that psychotic symptoms can be a feature of many different diagnoses at different stages of life. Understanding the risk factors helps clinicians to contemplate primary, secondary and tertiary preventive strategies that it may be possible to implement. In this second article of a three-part series, the psychosis risk timeline is again considered, here focusing on risk factors more likely to be encountered during later childhood, adolescence and adulthood. These include environmental factors, substance misuse, and social and psychopathological aspects.

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DECLARATION OF INTEREST:

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