Efficacy of Cannabidiol for Δ-9-Tetrahydrocannabinol-Induced Psychotic Symptoms, Schizophrenia, and Cannabis Use Disorders: A Narrative Review

Is There a Dose-Response Relationship Between Cannabis Use and Violence? A Longitudinal Study in Individuals with Severe Mental Disorders

Introduction: Recent longitudinal studies point toward the existence of a positive relationship between cannabis use and violence in people with severe mental disorders (SMD). However, the existence of a dose-response relationship between the frequency/severity of cannabis use and violence has seldom been investigated. Therefore, this study aims to determine if such a relationship exists in a psychiatric population. Methods: To do so, a total of 98 outpatients (81 males and 17 females, all over 18 years of age) with SMD were recruited at the Institut universitaire de santé mentale de Montréal (Montréal, Canada) and included in the analyses. Clinical evaluations were conducted every 3 months for a year. Substance use, violent behaviors, and potential covariables were assessed through self-reported assessments, urinary testing, as well as clinical, criminal, and police records. Using generalized estimating equations, the association between cannabis use frequency (nonusers, occasional, regular, and frequent users) and violence was investigated, as well as the association between the severity of cannabis use and violent behaviors. Results: It was found that cannabis use frequency and severity were significant predictors of violent behaviors. After adjustment for time, age, sex, ethnicity, diagnoses, impulsivity, and use of alcohol and stimulants, odds ratios were of 1.91 (p<0.001) between each frequency profile and 1.040 (p<0.001) for each increase of one point of the severity of cannabis use score (ranging from 0 to 79). Conclusions: Despite the high attrition rate, these findings may have important implications for clinicians as cannabis use may have serious consequences in psychiatric populations. Nevertheless, the mechanisms underlying this association remain unclear.

The Effects of Cannabidiol and δ-9-Tetrahydrocannabinol in Social Cognition: A Naturalistic Controlled Study

Background: Social cognition abilities such as empathy and the Theory of Mind (ToM) have been shown to be impaired in neuropsychiatric conditions such as psychotic, autistic, and bipolar disorders. The endocannabinoid system (ECS) seems to play a role in social behavior and emotional processing while it also seems to play a role in those neuropsychiatric conditions showing social cognition impairments. Main plant cannabinoids delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) modulate the ECS and, due to their opposite effects, have been proposed as both cause and treatment for neuropsychiatric-related disorders such as schizophrenia, anxiety, or post-traumatic stress disorder (PTSD). The aim of this study was to test the effects of THC and CBD on social cognition abilities in chronic cannabis users. Method: Eighteen members from a cannabis social club were tested for social cognition effects under the effects of different full spectrum cannabis extracts containing either THC, CBD, THC+CBD, or placebo in a naturalistic randomized double-blind crossover placebo-controlled study. Results: Results showed that participants under the effects of THC showed lower cognitive empathy when compared with the effects of CBD but not when those were compared with THC+CBD or placebo. Also, participants showed higher cognitive ToM under the effects of CBD when compared with the effects of placebo, but not when those were compared with THC or THC+CBD. However, we did not find differences on the emotional scales for empathy or ToM. Conclusions: This study provides evidence for the interaction between the effects of THC and CBD and social cognition abilities in a naturalistic environment, which can be of special interest for the clinical practice of medical cannabis on neuropsychiatric disorders. We show for the first time that CBD can improve ToM abilities in chronic cannabis users. Our results might help to understand the role of the ECS in social cognition, and their association with psychiatric and neurodevelopmental disorders such as schizophrenia or autism. Finally, we demonstrate how reliable methodologies can be implemented in naturalistic environments to collect valid ecological evidence outside classic laboratory settings.

Motivations for Cannabis Use in Individuals with Social Anxiety Disorder (SAD)

Social anxiety disorder (SAD) is a debilitating psychiatric condition. Consequently, it is common for those affected to resort to cannabis to cope with their symptoms. The primary objective of this study was to understand the differences between motivations for cannabis use in adults with and without SAD. We employed convergent, mixed methods to collect the data. Twenty-six individuals (age: 27.9 ± 7.3 years; 54% female) with and twenty-six (age: 27.4 ± 6.7 years; 50% female) without SAD were administered Marijuana Motives Measure (MMM). Motivations to initiate, continue, and maintain cannabis use were assessed in 12/26 participants in both groups using in-depth interviews. Cannabis weekly consumption was 3.8-fold and frequency 1.3-fold higher in the SAD group. Coping (F = 10.02; p <0.001; η2 = 0.46) and social (F = 2.81; p = 0.036; η2 = 0.19) motivations were also higher in the SAD group, after controlling for age, sex, and current CUD. The need to cope with symptoms of SAD may have been the driving force for repeated cannabis consumption. Psychoeducational programs educating children about the risk of using cannabis to cope with SAD should be implemented in vocational settings early on.

Recreational cannabis: Profile of cannabinoids present in marijuana samples supplied by the consuming population

As cannabis/marijuana is one of the most consumed psychoactive substances in the world, knowing the composition and type of cannabis sold in urban environments is a necessary input for the design of public health policies based on scientific evidence. This study characterized the main phytocannabinoids of marijuana samples (cigarettes or buds) obtained in urban and rural areas of the city of Medellín in October 2021. Non-probabilistic convenience sampling was carried out in which 87 marijuana samples donated by consumers were collected at different collection points throughout the city, and gas chromatography-mass spectrometry and flame ionization techniques were employed for the characterization of phytocannabinoids. Tetrahydrocannabinol (THC) was found to be the main constituent of circulating marijuana in Medellín, where 67.8% of the samples had a high or higher toxicological range for THC; the foregoing in a context where the deregulated market in practice limits the possibility that consumers have to calibrate or decide the concentration of cannabinoids in their doses.

Sex Differences in the Neuropsychiatric Effects and Pharmacokinetics of Cannabidiol: A Scoping Review

Cannabidiol (CBD) is a non-intoxicating cannabinoid compound with diverse molecular targets and potential therapeutic effects, including effects relevant to the treatment of psychiatric disorders. In this scoping review, we sought to determine the extent to which sex and gender have been considered as potential moderators of the neuropsychiatric effects and pharmacokinetics of CBD. In this case, 300 articles were screened, retrieved from searches in PubMed/Medline, Scopus, Google Scholar, PsycInfo and CINAHL, though only 12 met our eligibility criteria: eight studies in preclinical models and four studies in humans. Among the preclinical studies, three suggested that sex may influence long-term effects of gestational or adolescent exposure to CBD; two found no impact of sex on CBD modulation of addiction-relevant effects of Δ⁹-tetrahydrocannabinol (THC); two found antidepressant-like effects of CBD in males only; and one found greater plasma and liver CBD concentrations in females compared to males. Among the human studies, two found no sex difference in CBD pharmacokinetics in patient samples, one found greater plasma CBD concentrations in healthy females compared to males, and one found no evidence of sex differences in the effects of CBD on responses to trauma recall in patients with post-traumatic stress disorder (PTSD). No studies were identified that considered the role of gender in CBD treatment effects. We discuss potential implications and current limitations of the existing literature.

Understanding the Potential Benefits of Cannabidiol for Patients With Schizophrenia: A Narrative Review

Research suggests that cannabis-derived delta-9-tetrahydrocannabinol can be linked to the worsening of psychosis and/or other symptoms of schizophrenia. However, studies have shown that another major cannabinoid found in cannabis, cannabidiol (CBD), may be a potential alternative or adjunctive treatment for psychosis and schizophrenia. As such, herein we review the relevant literature relating to the safety and efficacy of CBD treatment in patients with schizophrenia, including the effects of CBD in treating the positive, negative, and cognitive symptoms of the disorder, as well as the molecular mechanisms by which CBD can reduce schizophrenic symptoms. The potential utility of CBD for mitigating cannabis cravings and cannabis withdrawal in this patient population will also be reviewed. Lastly, the dosing, method of drug delivery, length of treatment, and adverse effects of CBD in patients with schizophrenia are discussed. Thus, the goal of this narrative review is to help clinicians and researchers better understand the risks and benefits of this potential therapy for this patient population.

Phytocannabinoids and schizophrenia: Focus on adolescence as a critical window of enhanced vulnerability and opportunity for treatment

The recent shift in socio-political debates and growing liberalization of Cannabis use across the globe has raised concern regarding its impact on vulnerable populations such as adolescents. Concurrent with declining perception of Cannabis harms, more adolescents are using it daily in several countries and consuming marijuana strains with high content of psychotropic delta (9)-tetrahydrocannabinol (THC). These dual, related trends seem to facilitate the development of compromised social and cognitive performance at adulthood, which are described in preclinical and human studies. Cannabis exerts its effects via altering signalling within the endocannabinoid system (ECS), which modulates the stress circuitry during the neurodevelopment. In this context early interventions appear to circumvent the emergence of adult neurodevelopmental deficits. Accordingly, Cannabis sativa second-most abundant compound, cannabidiol (CBD), emerges as a potential therapeutic agent to treat neuropsychiatric disorders. We first focus on human and preclinical studies on the long-term effects induced by adolescent THC exposure as a "critical window" of enhanced neurophysiological vulnerability, which could be involved in the pathophysiology of schizophrenia and related primary psychotic disorders. Then, we focus on adolescence as a "window of opportunity" for early pharmacological treatment, as novel risk reduction strategy for neurodevelopmental disorders. Thus, we review current preclinical and clinical evidence regarding the efficacy of CBD in terms of positive, negative and cognitive symptoms treatment, safety profile, and molecular targets.

The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems. In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development. The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development. The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases. This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as "C. sativa L." or "medical cannabis"), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.

The Impact of THC and CBD in Schizophrenia: A Systematic Review

Background: People with schizophrenia are more likely to develop cannabis use disorder (CUD) and experience worse outcomes with use. Yet as cannabis is legalized for medical and recreational use, there is interest in its therapeutic potential. Objectives: To conduct a systematic review summarizing the design and results of controlled trials using defined doses of THC and CBD in schizophrenia. Method: A keyword search of eight online literature databases identified 11 eligible reports. Results: One placebo controlled trial (13 stable patients without CUD) found that intravenous THC increased psychosis and worsened learning/recall. Two reports of a functional magnetic resonance (fMRI) study of smoked or oral THC in 12 abstinent patients with schizophrenia and CUD found no change in symptoms and cognition, and an amelioration of impaired resting state brain function in areas implicated in reward function and the default mode network. One 4 week trial in acutely psychotic inpatients without CUD (mean age 30 y) found 800 mg CBD to be similarly efficacious to amisupride in improving psychosis and cognition. Two 6 week studies of CBD augmentation of antipsychotics in stable outpatients reported mixed results: CBD 600 mg was not more effective than placebo; CBD 1,000 mg reduced symptoms in a sample that did not exclude cannabis use and CUD. A brain fMRI and proton magnetic resonance spectroscopy study of single dose CBD in a sample that did not exclude CUD and cannabis use found that CBD improved symptoms and brain function during a learning/recall task and was associated with increased hippocampal glutamate. Discussion: There is substantial heterogeneity across studies in dose, method of drug delivery, length of treatment, patient age, whether patients with cannabis use/CUD were included or excluded, and whether patients were using antipsychotic medication. Conclusion: There is insufficient evidence for an effect of THC or CBD on symptoms, cognition, and neuroimaging measures of brain function in schizophrenia. At this time, research does not support recommending medical cannabis (THC or CBD) for treating patients with schizophrenia. Further research should examine THC and CBD in schizophrenia with and without comorbid CUD and consider the role of CBD in mitigating symptom exacerbation from THC.