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Brain Research Dec 2015Marijuana is the most popular illegal drug worldwide. Recent trends indicate that this may soon change; not due to decreased marijuana use, but to an amendment in... (Review)
Review
Marijuana is the most popular illegal drug worldwide. Recent trends indicate that this may soon change; not due to decreased marijuana use, but to an amendment in marijuana's illegal status. The cannabinoid type 1 (CB1) receptor mediates marijuana's psychoactive and reinforcing properties. CB1 receptors are also part of the brain endocannabinoid (eCB) system and support numerous forms of learning and memory, including the conditioned reinforcing properties of cues predicting reward or punishment. This is accomplished via eCB-dependent alterations in mesolimbic dopamine function, which plays an obligatory role in reward learning and motivation. Presynaptic CB1 receptors control midbrain dopamine neuron activity and thereby shape phasic dopamine release in target regions, particularly the nucleus accumbens (NAc). By also regulating synaptic input to the NAc, CB1 receptors modulate NAc output onto downstream neurons of the basal ganglia motor circuit, and thereby support goal-directed behaviors. Abused drugs promote short- and long-term adaptations in eCB-regulation of mesolimbic dopamine function, and thereby hijack neural systems related to the pursuit of rewards to promote drug abuse. By pharmacologically targeting the CB1 receptors, marijuana has preferential access to this neuronal system and can potently alter eCB-dependent processing of reward-related stimuli. As marijuana legalization progresses, greater access to this drug should increase the utility of marijuana as a research tool to better understand the eCB system, which has the potential to advance cannabinoid-based treatments for drug addiction.
Topics: Animals; Brain; Cannabinoids; Dopamine; Humans; Marijuana Abuse; Marijuana Smoking; Reward
PubMed: 25463025
DOI: 10.1016/j.brainres.2014.11.034 -
International Journal of Environmental... Jul 2023Regular cannabis use during adolescence can lead to cognitive, psychological, and social consequences, causing significant distress. Although psychological interventions... (Review)
Review
Regular cannabis use during adolescence can lead to cognitive, psychological, and social consequences, causing significant distress. Although psychological interventions are the mainstay type of treatment for cannabis use disorder, the results remain mixed among youths. The objective of this review is twofold: to identify the existing psychological interventions for cannabis use among youths, and to assess the evidence regarding the effectiveness of those interventions. Randomized controlled trials focused exclusively on cannabis use among adolescents and young adults were included. Three databases-Embase, PsycInfo, and PubMed-were searched to identify relevant peer-reviewed manuscripts published before February 2022 in English and French. The risk of bias was assessed using the Cochrane Collaboration's tool. Twenty-five randomized controlled trials were included. Fourteen studies reported a significant outcome related to cannabis use. These were mainly non-intensive, online interventions that aimed to improve the patients' relationships and emotion regulation. This review highlights the need to conduct additional randomized control trials that target cannabis use disorder specifically among adolescents. These randomized control trials should also aim to reduce the risk of bias related to psychiatric comorbidities as well as detection and attrition problems.
Topics: Humans; Adolescent; Young Adult; Cannabis; Psychosocial Intervention; Marijuana Abuse; Randomized Controlled Trials as Topic
PubMed: 37510578
DOI: 10.3390/ijerph20146346 -
European Addiction Research 2017This paper explores European and national trends in specialised drug treatment entry for cannabis-related problems. The analysis is based on data for the years 2003-2014... (Review)
Review
This paper explores European and national trends in specialised drug treatment entry for cannabis-related problems. The analysis is based on data for the years 2003-2014 from 22 European countries. Between 2003 and 2014, the overall number and proportion of primary cannabis-related first-time entrants increased significantly. A joinpoint regression analysis indicates that the overall increase of cannabis treatment entries is continuous, although country-related differences are observed. Possible explanations for the increase and different time trends are discussed including an increase in cannabis prevalence and cannabis-related problems, changes in risk perception, increases in cannabis potency, changes in referral practices and increased availability and accessibility of treatment services.
Topics: Cannabis; Europe; Humans; Marijuana Abuse; Substance Abuse Treatment Centers; Substance-Related Disorders
PubMed: 28511182
DOI: 10.1159/000475810 -
Addiction (Abingdon, England) Sep 2017The relationship between cannabis and psychosis and schizophrenia has tested the field of addiction for decades, and in some ways serves as measure of our ability to... (Review)
Review
The relationship between cannabis and psychosis and schizophrenia has tested the field of addiction for decades, and in some ways serves as measure of our ability to provide a credible contribution to public health. As cannabis is used widely, many people are interested in the risks the drug poses to mental health. This paper focuses upon a seminal study examining this, the trajectory of subsequent research findings and what this has meant for understanding and communicating risk factor information. These studies provided evidence of a dose-response relationship between cannabis and psychosis, and that for those individuals with schizophrenia cannabis exacerbated their symptoms. The findings fit with a multi-causal model in which vulnerability interacts with a precipitating agent to produce a disease outcome. Even though this is a common model in epidemiology, it has proved difficult to communicate it in this case. This may be because at a population level the increased risk is weak and the vulnerabilities relatively rare. It may also be because people bring strongly held preconceptions to interpreting a complex multi-causal phenomenon.
Topics: Humans; Marijuana Abuse; Psychotic Disorders; Risk Factors; Schizophrenia
PubMed: 28419656
DOI: 10.1111/add.13826 -
European Addiction Research 2016Many studies have examined factors associated with the first onset of cannabis use and abuse. Currently, there is relatively little research regarding conditions under... (Review)
Review
BACKGROUND
Many studies have examined factors associated with the first onset of cannabis use and abuse. Currently, there is relatively little research regarding conditions under which cannabis dependence is more likely to emerge. Although previous studies have examined different potential determinants of cannabis dependence, to our knowledge, a systematic review is lacking.
AIMS
The study aims to identify recent findings regarding psychosocial determinants of cannabis dependence and to summarize them systematically.
METHODS
A literature search in 4 databases - Embase, Medline, PsycINFO and PSYNDEX - was conducted. Searches were limited to publications between 2000 and April 2014, English and German as languages and humans as study subjects.
RESULTS
Our search detected a total of 10,568 studies. Twenty-six studies finally met inclusion criteria. Consumption patterns such as a regular cannabis use independent of social context and an early onset of use (11-15 years) were correlates of cannabis dependence. Moreover, early reactions to cannabis use and coping-oriented use motives explained additional variance. Stress factors and critical life events such as parental separation and early parental death as well as mental and social conflicts have also been linked with development of cannabis dependence. Additionally, comorbid mental disorders correlated with cannabis dependence.
CONCLUSION
Numerous factors were shown to have an impact on transition to cannabis dependence. In particular, a wide range of mental disorders has been linked to an elevated risk of becoming dependent. The development of a dependence syndrome seems to be associated with diverse processes, in which social, biological and intra-individual factors interact in a complex manner. Nevertheless, the link between cannabis dependence and predisposing factors could not be resolved convincingly by most studies due to methodological weaknesses regarding dependence criteria.
Topics: Comorbidity; Diagnosis, Dual (Psychiatry); Humans; Marijuana Abuse; Mental Disorders; Risk Factors
PubMed: 26551358
DOI: 10.1159/000441777 -
The American Journal of Drug and... Jul 2017The use of cannabis has garnered more attention recently with ongoing efforts at marijuana legalization. The consequences of cannabis use are not clearly understood and... (Review)
Review
BACKGROUND
The use of cannabis has garnered more attention recently with ongoing efforts at marijuana legalization. The consequences of cannabis use are not clearly understood and remain a concern.
OBJECTIVES
To review the acute and persistent effects of cannabis use and associations with psychiatric disorders.
METHODS
Using Pubmed and PsychInfo, we conducted a narrative review of the literature on cannabis and psychiatric comorbidity using the keywords cannab*, marijuana, schizo*, psychosis, mood, depression, mania, bipolar, and anxiety.
RESULTS
There is substantial evidence of cannabis use leading to other illicit drug use and of an association between cannabis use and psychosis. A few reports suggest an association with bipolar disorder while the association with depression and anxiety disorders is mixed.
CONCLUSIONS
Whenever an association is observed between cannabis use and psychiatric disorders, the relationship is generally an adverse one. Age at the time of cannabis use appears to be an important factor with stronger associations observed between adolescent onset cannabis use and later onset of psychiatric disorders. Additional studies taking into account potential confounds (such as withdrawal symptoms, periods of abstinence, and other substance use) and moderators (such as age of initiation of cannabis use, the amount and frequency of drug use, prior history of childhood maltreatment, and gender) are needed to better understand the psychiatric consequences of cannabis use.
Topics: Adolescent; Age Factors; Age of Onset; Diagnosis, Dual (Psychiatry); Humans; Marijuana Abuse; Marijuana Smoking; Mental Disorders; Substance-Related Disorders
PubMed: 27612527
DOI: 10.1080/00952990.2016.1213273 -
Addiction (Abingdon, England) Mar 2020To summarize and evaluate our knowledge of the relationship between heavy cannabis use, cannabis use disorder (CUD) and the brain. (Review)
Review
AIMS
To summarize and evaluate our knowledge of the relationship between heavy cannabis use, cannabis use disorder (CUD) and the brain.
METHODS
Narrative review of relevant literature identified through existing systematic reviews, meta-analyses and a PubMed search. Epidemiology, clinical representations, potential causal mechanisms, assessments, treatment and prognosis are discussed.
RESULTS
Although causality is unclear, heavy and dependent cannabis use is consistently associated with a high prevalence of comorbid psychiatric disorders and learning and memory impairments that seem to recover after a period of abstinence. Evidence regarding other cognitive domains and neurological consequences, including cerebrovascular events, is limited and inconsistent. Abstinence after treatment is only achieved in a minority of cases; treatment targeted at reduction in use appears have some success. Potential moderators of the impact of CUD on the brain include age of onset, heaviness of use, CUD severity, the ratio of ∆9-tetrahydrocannabinol to cannabidiol and severity of comorbid disorders.
CONCLUSIONS
Current evidence of long-term effects of daily cannabis use and cannabis use disorder on brain-related outcomes is suggestive rather than conclusive, but use is associated with psychiatric morbidity and with cognitive impairments that recover after a period of abstinence.
Topics: Age of Onset; Brain; Causality; Cognition; Cognitive Dysfunction; Comorbidity; Dronabinol; Humans; Marijuana Abuse; Mental Disorders
PubMed: 31408248
DOI: 10.1111/add.14776 -
The International Journal on Drug Policy Apr 2017Social attitudes and cultural norms around the issue of substance abuse are shifting rapidly around the world, leading to complex and unpredictable consequences. On the... (Review)
Review
Social attitudes and cultural norms around the issue of substance abuse are shifting rapidly around the world, leading to complex and unpredictable consequences. On the positive side, efforts to more intensely disseminate the scientific evidence for the many connections between chronic substance use and the emergence of measurable and discrete brain dysfunctions, has ushered in an evolving climate of acceptance and a new era of improved access to more effective interventions, at least in the United States. On the negative side, there has been a steady erosion in the public perception of the harms associated with the use of popular drugs, especially cannabis. This worrisome trend has sprouted at the convergence of several forces that have combined, more or less fortuitously, to effectively change long-standing policies away from prohibition and toward decriminalization or legalization. These forces include the outsized popularity of the cannabis plant among recreational users, the unflagging campaign by corporate lobbyists and patient advocates to mainstream its medicinal use, and the honest realization in some quarters of the deleterious impact of the drug war and its draconian cannabis laws, in particular, on society's most vulnerable populations. Updating drug policies is a desirable goal, and significant changes may indeed be warranted. However, there is a real concern when policy changes are hurriedly implemented without the required input from the medical, scientific, or policy research communities. Regardless of how well intentioned, such initiatives are bound to magnify the potential for unintended adverse consequences in the form of far ranging health and social costs. To minimize this risk, science must be front and center in this important policy debate. Here, we review the state of the science on cannabis and cannabinoid health effects, both adverse and therapeutic. We focus on the prevalence of use in different populations, the mechanisms by which cannabis exerts its effects (i.e., via the endocannabinoid system), and the double-edged potential of this system to inspire new medications, on one hand, and to cause short and long term harmful effects on the other. By providing knowledge of cannabis' broad ranging effects, we hope to enable better decision making regarding cannabis legislation and policy implementation.
Topics: Endocannabinoids; Humans; Legislation, Drug; Marijuana Abuse; Medical Marijuana; Plant Extracts; Public Policy; Science
PubMed: 28189459
DOI: 10.1016/j.drugpo.2017.01.007 -
Medical Science Monitor : International... May 2023Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder in children and adults. In the substance use disorders (SUDs) population, ADHD... (Review)
Review
Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder in children and adults. In the substance use disorders (SUDs) population, ADHD prevalence reaches 23.1%, leading to more severe substance abuse progression and reduced treatment effectiveness. Cannabis is the most common illicit drug used among the ADHD population. The increasing popularity of medical marijuana (MM) has raised concerns about its potential impact on neurocognitive functions, particularly in adolescents. Persistent cannabis use can cause permanent changes in brain structures and circuits. This review aims to overview the comorbidity of ADHD and SUDs, focusing on cannabis use disorders. Theoretical models of the etiologies of ADHD and SUDs were investigated to establish a framework for analyzing their underlying neurocognitive mechanisms. The reward and motivational brain circuitries involving the default-mode network and the endocannabinoid system were emphasized. The high prevalence of SUDs in the ADHD population has ramifications, including earlier age of onset, self-medication, and reduced performance in various domains. Cannabis use disorders are particularly significant due to the increasingly widespread use of cannabis and its perceived safety. The review highlights the lack of theoretical background on the therapeutic properties of medicinal cannabis, criticizing its speculated applications in the ADHD population. This article reviews the current understanding of the association between ADHD and cannabis use, emphasizing the need for further research and a cautious approach to MM's potential therapeutic applications.
Topics: Adult; Adolescent; Child; Humans; Attention Deficit Disorder with Hyperactivity; Marijuana Abuse; Substance-Related Disorders; Brain; Comorbidity
PubMed: 37147797
DOI: 10.12659/MSM.939749 -
Viruses Jun 2021Cannabis continues to be the most used drug in the world today. Research shows that cannabis use is associated with a wide range of adverse health consequences that may... (Review)
Review
Cannabis continues to be the most used drug in the world today. Research shows that cannabis use is associated with a wide range of adverse health consequences that may involve almost every physiological and biochemical system including respiratory/pulmonary complications such as chronic cough and emphysema, impairment of immune function, and increased risk of acquiring or transmitting viral infections such as HIV, HCV, and others. The review of published research shows that cannabis use may impair immune function in many instances and thereby exerts an impact on viral infections including human immune deficiency virus (HIV), hepatitis C infection (HCV), and human T-cell lymphotropic type I and II virus (HTLV-I/II). The need for more research is also highlighted in the areas of long-term effects of cannabis use on pulmonary/respiratory diseases, immune dysfunction and the risk of infection transmission, and the molecular/genetic basis of immune dysfunction in chronic cannabis users.
Topics: HIV Infections; HTLV-II Infections; Hepatitis C; Humans; Immune System; Marijuana Abuse; Virus Diseases
PubMed: 34207524
DOI: 10.3390/v13061099