A systematic review of the effect of cannabidiol on cognitive function: Relevance to schizophrenia

Therapeutic-like activity of cannabidiolic acid methyl ester in the MK-801 mouse model of schizophrenia: Role for cannabinoid CB1 and serotonin-1A receptors

Schizophrenia is a psychotic disorder with an increasing prevalence and incidence over the last two decades. The condition presents with a diverse array of positive, negative, and cognitive impairments. Conventional treatments often yield unsatisfactory outcomes, especially with negative symptoms. We investigated the role of prefrontocortical (PFC) N-methyl-D-aspartate receptors (NMDARs) in the pathophysiology and development of schizophrenia. We explored the potential therapeutic effects of cannabidiolic acid (CBDA) methyl ester (HU-580), an analogue of CBDA known to act as an agonist of the serotonin-1A receptor (5-HT1AR) and an antagonist of cannabinoid type 1 receptor (CB1R). C57BL/6 mice were intraperitoneally administered the NMDAR antagonist, dizocilpine (MK-801, .3 mg/kg) once daily for 17 days. After 7 days, they were concurrently given HU-580 (.01 or .05 μg/kg) for 10 days. Behavioural deficits were assessed at two time points. We conducted enzyme-linked immunosorbent assays to measure the concentration of PFC 5-HT1AR and CB1R. We found that MK-801 effectively induced schizophrenia-related behaviours including hyperactivity, social withdrawal, increased forced swim immobility, and cognitive deficits. We discovered that low-dose HU-580 (.01 μg/kg), but not the high dose (.05 μg/kg), attenuated hyperactivity, forced swim immobility and cognitive deficits, particularly in female mice. Our results revealed that MK-801 downregulated both CB1R and 5-HT1AR, an effect that was blocked by both low- and high-dose HU-580. This study sheds light on the potential antipsychotic properties of HU-580, particularly in the context of NMDAR-induced dysfunction. Our findings could contribute significantly to our understanding of schizophrenia pathophysiology and offer a promising avenue for exploring the therapeutic potential of HU-580 and related compounds in alleviating symptoms.

Effects of acute cannabidiol on behavior and the endocannabinoid system in HIV-1 Tat transgenic female and male mice

Background

Some evidence suggests that cannabidiol (CBD) has potential to help alleviate HIV symptoms due to its antioxidant and anti-inflammatory properties. Here we examined acute CBD effects on various behaviors and the endocannabinoid system in HIV Tat transgenic mice.

Methods

Tat transgenic mice (female/male) were injected with CBD (3, 10, 30 mg/kg) and assessed for antinociception, activity, coordination, anxiety-like behavior, and recognition memory. Brains were taken to quantify endocannabinoids, cannabinoid receptors, and cannabinoid catabolic enzymes. Additionally, CBD and metabolite 7-hydroxy-CBD were quantified in the plasma and cortex.

Results

Tat decreased supraspinal-related nociception and locomotion. CBD and sex had little to no effects on any of the behavioral measures. For the endocannabinoid system male sex was associated with elevated concentration of the proinflammatory metabolite arachidonic acid in various CNS regions, including the cerebellum that also showed higher FAAH expression levels for Tat(+) males. GPR55 expression levels in the striatum and cerebellum were higher for females compared to males. CBD metabolism was altered by sex and Tat expression.

Conclusion

Findings indicate that acute CBD effects are not altered by HIV Tat, and acute CBD has no to minimal effects on behavior and the endocannabinoid system.

A phase III multisite randomised controlled trial to compare the efficacy of cannabidiol to placebo in the treatment of cannabis use disorder: the CBD-CUD study protocol

BACKGROUND

Cannabis use disorder (CUD) is increasingly common and contributes to a range of health and social problems. Cannabidiol (CBD) is a non-intoxicating cannabinoid recognised for its anticonvulsant, anxiolytic and antipsychotic effects with no habit-forming qualities. Results from a Phase IIa randomised clinical trial suggest that treatment with CBD for four weeks reduced non-prescribed cannabis use in people with CUD. This study examines the efficacy, safety and quality of life of longer-term CBD treatment for patients with moderate-to-severe CUD.

METHODS/DESIGN

A phase III multi-site, randomised, double-blinded, placebo controlled parallel design of a 12-week course of CBD to placebo, with follow-up at 24 weeks after enrolment. Two hundred and fifty adults with moderate-to-severe CUD (target 20% Aboriginal), with no significant medical, psychiatric or other substance use disorders from seven drug and alcohol clinics across NSW and VIC, Australia will be enrolled. Participants will be administered a daily dose of either 4 mL (100 mg/mL) of CBD or a placebo dispensed every 3-weeks. All participants will receive four-sessions of Cognitive Behavioural Therapy (CBT) based counselling. Primary endpoints are self-reported cannabis use days and analysis of cannabis metabolites in urine. Secondary endpoints include severity of CUD, withdrawal severity, cravings, quantity of use, motivation to stop and abstinence, medication safety, quality of life, physical/mental health, cognitive functioning, and patient treatment satisfaction. Qualitative research interviews will be conducted with Aboriginal participants to explore their perspectives on treatment.

DISCUSSION

Current psychosocial and behavioural treatments for CUD indicate that over 80% of patients relapse within 1-6 months of treatment. Pharmacological treatments are highly effective with other substance use disorders but there are no approved pharmacological treatments for CUD. CBD is a promising candidate for CUD treatment due to its potential efficacy for this indication and excellent safety profile. The anxiolytic, antipsychotic and neuroprotective effects of CBD may have added benefits by reducing many of the mental health and cognitive impairments reported in people with regular cannabis use.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Registry: ACTRN12623000526673 (Registered 19 May 2023).

Ameliorative Effect of Cannabidiol on Topiramate-Induced Memory Loss: The Role of Hippocampal and Prefrontal Cortical NMDA Receptors and CREB/BDNF Signaling Pathways in Rats

Cannabidiol (CBD) is a promising neurological agent with potential beneficial effects on memory and cognitive function. The combination of CBD and topiramate in the treatment of some neurological diseases has been of great interest. Since Topiramate-induced memory loss is a major drawback of its clinical application and the overall effect of the combination of CBD and topiramate on memory is still unclear, here we investigated the effect of CBD on topiramate-induced memory loss and the underlying molecular mechanisms. A one trial step-through inhibitory test was used to evaluate memory consolidation in rats. Moreover, the role of N-methyl-D-aspartate receptors (NMDARs) in the combination of CBD and topiramate in memory consolidation was evaluated through the intra-CA1 administration of MK-801 and NMDA. Western blot analysis was used to evaluate variations in brain-derived neurotrophic factor (BDNF) and phosphorylated cyclic AMP response element-binding protein (pCREB)/CREB ratio in the prefrontal cortex (PFC) and hippocampus (HPC). While the intraperitoneal (i.p.) administration of topiramate (50, 75, and 100 mg/kg) significantly reduced inhibitory time latency, the i.p. administration of CBD (20 and 40 mg/kg) could effectively reverse these effects. Similarly, the sub-effective doses of NMDA plus CBD (10 mg/kg) could improve the topiramate-induced memory loss along with an enhancement in BDNF and pCREB expression in the PFC and HPC. Contrarily, the administration of sub-effective doses of the NMDAR antagonist (MK-801) diminished the protective effects of CBD (20 mg/kg) on topiramate-induced memory loss associated with decreased BDNF and pCREB levels in the PFC and HPC. These findings suggest that CBD can improve topiramate-induced memory impairment, partially by the NMDARs of the PFC and HPC, possibly regulated by the CREB/BDNF signaling pathway.

THC improves behavioural schizophrenia-like deficits that CBD fails to overcome: a comprehensive multilevel approach using the Poly I:C maternal immune activation

Prenatal infections and cannabis use during adolescence are well-recognized risk factors for schizophrenia. As inflammation and oxidative stress (OS) contribute to this disorder, anti-inflammatory drugs have been proposed as potential therapies. This study aimed to evaluate the association between delta-9-tetrahydrocannabinol (THC) and schizophrenia-like abnormalities in a maternal immune activation (MIA) model. Additionally, we assessed the preventive effect of cannabidiol (CBD), a non-psychotropic/anti-inflammatory cannabinoid. THC and/or CBD were administered to Saline- and MIA-offspring during periadolescence. At adulthood, THC-exposed MIA-offspring showed significant improvements in sensorimotor gating deficits. Structural and metabolic brain changes were evaluated by magnetic resonance imaging, revealing cortical shrinkage in Saline- and enlargement in MIA-offspring after THC-exposure. Additionally, MIA-offspring displayed enlarged ventricles and decreased hippocampus, which were partially reverted by both cannabinoids. CBD prevented THC-induced reduction in the corpus callosum, despite affecting white matter structure. Post-mortem studies revealed detrimental effects of THC, including increased inflammation and oxidative stress. CBD partially reverted these pro-inflammatory alterations and modulated THC's effects on the endocannabinoid system. In conclusion, contrary to expectations, THC exhibited greater behavioural and morphometric benefits, despite promoting a pro-inflammatory state that CBD partially reverted. Further research is needed to elucidate the underlying mechanisms involved in the observed benefits of THC.

Effects of Cannabidiol Interactions with CYP2R1, CYP27B1, CYP24A1, and Vitamin D3 Receptors on Spatial Memory, Pain, Inflammation, and Aging in Vitamin D3 Deficiency Diet-Induced Rats

Introduction: The study was planned to investigate memory-enhancing, anti-inflammatory, and antiaging potential of cannabidiol (CBD) on vitamin D3 deficient diet (VDD)-induced rats. Materials and Methods: Cytochrome P-450 enzymes were analyzed by RT-PCR method and others biomarkers by enzyme-linked immunosorbent assay. Results: CYP2R1 and CYP27B1-mRNA were significantly increased by 39.29 and 38.37%, respectively, while; CYP24A1-mRNA was significantly reduced by 21.39% compared to VDD. Vitamin D3 receptor protein expression was significantly increased by 148.3%, 60.48%, and 142.03% in liver, kidney, and brain, respectively, compared to VDD group. Vitamin D3 metabolites and serotonin were significantly increased more than 60% and 100%, respectively, compared to VDD. Spatial memory (in terms of total distance, escape latency) and pain score were improved compared to VDD. Cytokines were significantly reduced than VDD. Besides, levels of superoxide dismutase (49.61%), glutathione peroxidase (178.87%), acetylcholine (25.40%), and klotho (145.57%) were significantly increased than VDD. Conclusions: Study findings supported that CBD interacts with CYP2R1, CYP27B1, CYP24A1, and vitamin D receptors, resulting in increased vitamin D3 metabolites, which improved memory, pain tolerance, reduced inflammation, and aging through modulating antioxidative enzymes, cytokines, and neurotransmitters in VDD-induced rats.

Effects of the Acute and Chronic Administration of Cannabidiol on Cognition in Humans and Animals: A Systematic Review

Introduction: The effects of cannabidiol (CBD) on cognition has been investigated in recent years to determine the therapeutic potential of this cannabinoid for a broad gamut of medical conditions, including neuropsychiatric disorders. The aim of the present study was to perform a systematic review of studies that analyzed the effects of the acute and chronic administration of CBD on cognition in humans and animals both to assess the cognitive safety of CBD and to determine a beneficial potential of CBD on cognition. Methods: The PubMed, Web of Science, PsycINFO, and Scopus databases were searched in December of 2022 for relevant articles using the following combinations of keywords: ("cannabidiol" OR "CBD") AND ("cognition" OR "processing cognitive" OR "memory" OR "language" OR "attention" OR "executive function" OR "social cognition" OR "perceptual motor ability" OR "processing speed"). Results: Fifty-nine articles were included in the present review (36 preclinical and 23 clinical trials). CBD seems not to have any negative effect on cognitive processing in rats. The clinical trials confirmed these findings in humans. One study found that repeated dosing with CBD may improve cognitive in people who use cannabis heavily but not individuals with neuropsychiatric disorders. Considering the context of neuropsychiatric disorders in animal models, CBD seems to reverse the harm caused by the experimental paradigms, such that the performance of these animals becomes similar to that of control animals. Conclusions: The results demonstrate that the chronic and acute administration of CBD seems not to impair cognition in humans without neuropsychiatric disorders. In addition, preclinical studies report promising results regarding the effects of CBD on the cognitive processing of animals. Future double-blind, placebo-controlled, randomized clinical trials with larger, less selective samples, with standardized tests, and using different doses of CBD in outpatients are of particular interest to elucidate the cognitive effects of CBD.

Cannabidiol versus placebo as adjunctive treatment in early psychosis: study protocol for randomized controlled trial

BACKGROUND

Psychotic disorders are a leading cause of disability in young adults. Antipsychotics have been the primary intervention for psychosis for over 60 years, and yet, we have made little progress in treating negative symptoms, neurocognition, and functional disability. There is growing evidence that cannabidiol (CBD) is effective in treating positive psychotic symptoms, possibly also negative and neurocognitive symptoms, and moreover is well tolerated compared to other psychotropic medications. Anecdotally, patients participating in the Cognitive Assessment and Risk Evaluation (CARE) Early Psychosis Treatment Program at the University of California, San Diego, are self-administering CBD and report subjective improvement in stress, anxiety, and ability to cope with symptoms. The overarching aim of the trial is to explore the effectiveness of CBD augmentation on symptoms and neurocognition in early psychosis while also exploring the mechanism of action of CBD and predictors of response to treatment. The mechanism by which cannabidiol has a therapeutic effect on psychosis is poorly understood. Recent evidence has suggested that CBD may reduce stress and pro-inflammatory biomarker levels. Endocannabinoids also have powerful roles in eating behavior, reward, and mood, indicating these neurotransmitters may play a role in reducing hyperphagia and metabolic abnormalities that are present early in the course of psychotic illness and exacerbated by antipsychotic medication. The neurophysiological effects of CBD have been studied in animal models of psychosis that show improvements in information processing in response to CBD, but there are no studies in individuals with early psychosis.

METHOD

A total of 120 individuals in the early stages of psychosis will be randomized to 1000 mg of CBD versus placebo as an adjunct to existing treatment in a 8-week, double-blind superiority randomized control trial. The primary outcome measures are symptoms and neurocognition.

DISCUSSION

We hypothesized that CBD will improve symptoms and neurocognition as well as secondary outcome measures of neurohormones, inflammation, eating behaviors, and information processing. Importantly, predictors, moderators, and mediators of the CBD effects will be examined. A better understanding of which individuals are likely to respond to CBD can inform treatment planning and personalize treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04411225. Registered on June 2, 2020.

Delta-9-Tetrahydrocannabinol, Cannabidiol, and Acute Psychotomimetic States: A Balancing Act of the Principal Phyto-Cannabinoids on Human Brain and Behavior

Background: THC and CBD are the principal phyto-cannabinoids in the cannabis plant. The differential and possibly antagonistic effects of these compounds on specific brain and behavioral responses, and the mechanisms underlying their effects have generated extensive interest in pre-clinical and clinical neuroscience investigations. Methods: In this double-blind randomized placebo-controlled counterbalanced Human Laboratory Study, we examined the effects of three different dose ratios of CBD:THC (1:1, 2:1, and 3:1) on "neural noise," an electrophysiological biomarker of psychosis known to be sensitive to cannabinoids as well as subjective and psychotomimetic effects. Healthy volunteers (n=28, 12 women) with at least one prior exposure to cannabis participated in the study. Outcomes: The lowest CBD (2.5 mg):THC (0.035 mg/kg) ratio (1:1) resulted in maximal attenuation of both THC-induced psychotomimetic effects (Positive and Negative Syndrome Scale [PANSS] positive: Anova Type Statistic [ATS]=7.83, pcorrected=0.015) and neural noise (ATS=8.83, pcorrected=0.009). Further addition of CBD did not reduce the subjective experience of THC-induced "high" (p>0.05 for all CBD doses). Interpretation: These novel results demonstrate that CBD attenuates specific THC-induced subjective and objective effects relevant to psychosis in a dose/ratio-dependent manner. Given the increasing global trend of cannabis liberalization and application for medical indications, these results assume considerable significance given the potential dose-related interactions of these key phyto-cannabinoids. Trial registration: The trial was registered in clinicaltrials.gov ID: NCT01180374.

CBD enhances the cognitive score of adolescent rats prenatally exposed to THC and fine-tunes relevant effectors of hippocampal plasticity

Introduction: An altered neurodevelopmental trajectory associated with prenatal exposure to ∆-9-tetrahydrocannabinol (THC) leads to aberrant cognitive processing through a perturbation in the effectors of hippocampal plasticity in the juvenile offspring. As adolescence presents a unique window of opportunity for "brain reprogramming", we aimed at assessing the role of the non-psychoactive phytocannabinoid cannabidiol (CBD) as a rescue strategy to temper prenatal THC-induced harm. Methods: To this aim, Wistar rats prenatally exposed to THC (2 mg/kg s.c.) or vehicle (gestational days 5-20) were tested for specific indexes of spatial and configural memory in the reinforcement-motivated Can test and in the aversion-driven Barnes maze test during adolescence. Markers of hippocampal excitatory plasticity and endocannabinoid signaling-NMDAR subunits NR1 and 2A-, mGluR5-, and their respective scaffold proteins PSD95- and Homer 1-; CB1R- and the neuromodulatory protein HINT1 mRNA levels were evaluated. CBD (40 mg/kg i.p.) was administered to the adolescent offspring before the cognitive tasks. Results: The present results show that prenatal THC impairs hippocampal memory functions and the underlying synaptic plasticity; CBD is able to mitigate cognitive impairment in both reinforcement- and aversion-related tasks and the neuroadaptation of hippocampal excitatory synapses and CB1R-related signaling. Discussion: While this research shows CBD potential in dampening prenatal THC-induced consequences, we point out the urgency to curb cannabis use during pregnancy in order to avoid detrimental bio-behavioral outcomes in the offspring.

The Effects of Cannabidiol on the Driving Performance of Healthy Adults: A Pilot RCT

Introduction

A common side effect of cannabidiol is drowsiness, which could impact safe driving. This study's purpose was to determine the feasibility and whether cannabidiol impacts simulated driving performance.

Methods

This was a randomized, parallel-group, sex-stratified, double-blind, pilot trial that consisted of a volunteer sample of healthy, currently driving college students. Participants were randomized and allocated to receive a placebo (n=19) or 300 mg cannabidiol (n=21) by oral syringe. Participants completed a ~40-minute driving simulation. A post-test survey assessed acceptability. The primary outcomes were mean SD of lateral position, total percent time the individual drove outside travel lanes, total collisions, time to initial collision, and mean brake reaction time. Outcomes were compared between groups using Student's t-tests and Cox proportional hazards models.

Results

None of the relationships were statistically significant, but the study was underpowered. Those receiving cannabidiol experienced slightly more collisions (0.90 vs 0.68, p=0.57) and had slightly higher mean SD of lateral position and slower brake reaction times (0.60 vs 0.58 seconds, p=0.61) than those who received placebo. Participants were satisfied with their experiences.

Conclusions

The design was feasible. Larger trials may be warranted because it is unclear whether the small differences in performance seen in the cannabidiol group were clinically relevant.

Mitofusin-2 mediates cannabidiol-induced neuroprotection against cerebral ischemia in rats

Cannabidiol (CBD) reportedly exerts protective effects against many psychiatric disorders and neurodegenerative diseases, but the mechanisms are poorly understood. In this study, we explored the molecular mechanism of CBD against cerebral ischemia. HT-22 cells or primary cortical neurons were subjected to oxygen-glucose deprivation insult followed by reoxygenation (OGD/R). In both HT-22 cells and primary cortical neurons, CBD pretreatment (0.1, 0.3, 1 μM) dose-dependently attenuated OGD/R-induced cell death and mitochondrial dysfunction, ameliorated OGD/R-induced endoplasmic reticulum (ER) stress, and increased the mitofusin-2 (MFN2) protein level in HT-22 cells and primary cortical neurons. Knockdown of MFN2 abolished the protective effects of CBD. CBD pretreatment also suppressed OGD/R-induced binding of Parkin to MFN2 and subsequent ubiquitination of MFN2. Overexpression of Parkin blocked the effects of CBD in reducing MFN2 ubiquitination and reduced cell viability, whereas overexpressing MFN2 abolished Parkin's detrimental effects. In vivo experiments were conducted on male rats subjected to middle cerebral artery occlusion (MCAO) insult, and administration of CBD (2.5, 5 mg · kg-1, i.p.) dose-dependently reduced the infarct volume and ER stress in the brains. Moreover, the level of MFN2 within the ischemic penumbra of rats was increased by CBD treatment, while the binding of Parkin to MFN2 and the ubiquitination of MFN2 was decreased. Finally, short hairpin RNA against MFN2 reversed CBD's protective effects. Together, these results demonstrate that CBD protects brain neurons against cerebral ischemia by reducing MFN2 degradation via disrupting Parkin's binding to MFN2, indicating that MFN2 is a potential target for the treatment of cerebral ischemia.

Cannabidiol: Bridge between Antioxidant Effect, Cellular Protection, and Cognitive and Physical Performance

The literature provides scientific evidence for the beneficial effects of cannabidiol (CBD), and these effects extend beyond epilepsy treatment (e.g., Lennox-Gastaut and Dravet syndromes), notably the influence on oxidative status, neurodegeneration, cellular protection, cognitive function, and physical performance. However, products containing CBD are not allowed to be marketed everywhere in the world, which may ultimately have a negative effect on health as a result of the uncontrolled CBD market. After the isolation of CBD follows the discovery of CB1 and CB2 receptors and the main enzymatic components (diacylglycerol lipase (DAG lipase), monoacyl glycerol lipase (MAGL), fatty acid amino hydrolase (FAAH)). At the same time, the antioxidant potential of CBD is due not only to the molecular structure but also to the fact that this compound increases the expression of the main endogenous antioxidant systems, superoxide dismutase (SOD), and glutathione peroxidase (GPx), through the nuclear complex erythroid 2-related factor (Nrf2)/Keep1. Regarding the role in the control of inflammation, this function is exercised by inhibiting (nuclear factor kappa B) NF-κB, and also the genes that encode the expression of molecules with a pro-inflammatory role (cytokines and metalloproteinases). The other effects of CBD on cognitive function and physical performance should not be excluded. In conclusion, the CBD market needs to be regulated more thoroughly, given the previously listed properties, with the mention that the safety profile is a very good one.

Effect of Cannabis on Memory Consolidation, Learning and Retrieval and Its Current Legal Status in India: A Review

Cannabis is one of the oldest crops grown, traditionally held religious attachments in various cultures for its medicinal use much before its introduction to Western medicine. Multiple preclinical and clinical investigations have explored the beneficial effects of cannabis in various neurocognitive and neurodegenerative diseases affecting the cognitive domains. Tetrahydrocannabinol (THC), the major psychoactive component, is responsible for cognition-related deficits, while cannabidiol (CBD), a non-psychoactive phytocannabinoid, has been shown to elicit neuroprotective activity. In the present integrative review, the authors focus on the effects of cannabis on the different cognitive domains, including learning, consolidation, and retrieval. The present study is the first attempt in which significant focus has been imparted on all three aspects of cognition, thus linking to its usage. Furthermore, the investigators have also depicted the current legal position of cannabis in India and the requirement for reforms.

Cannabinoids as Immune System Modulators: Cannabidiol Potential Therapeutic Approaches and Limitations

Introduction: Cannabidiol (CBD) is the second most abundant Phytocannabinoid in Cannabis extracts. CBD has a binding affinity for several cannabinoid and cannabinoid-associated receptors. Epidiolex (oral CBD solution) has been lately licensed by the Food and Drug Administration (FDA) for the treatment of pediatric epileptic seizures. Methods: In this review, we discussed the most promising applications of CBD for chronic inflammatory conditions, namely CBD's anti-inflammatory effects during inflammatory bowel disease, coronavirus disease (antiviral effect), brain pathologies (neuroprotective and anti-inflammatory properties), as well as CBD immunomodulatory and antitumoral activities in the tumor microenvironment. Special focus was shed on the main therapeutic mechanisms of action of CBD, particularly in the control of the immune system and the endocannabinoid system. Results: Findings suggest that CBD is a potent immunomodulatory drug as it has manifested immunosuppressive properties in the context of sterile inflammation (e.g., inflammatory bowel disease, rheumatoid arthritis, and neurodegenerative diseases), and immunoprotective effects during viral infections (e.g. COVID-19) Similarly, CBD has exhibited a selective response toward cancer types by engaging different targets and signaling pathways. These results are in favor of the primary function of the endocannabinoid system which is homeostatic maintenance. Conclusion: The presented evidence suggests that the endocannabinoid system is a prominent target for the treatment of inflammatory and autoimmune diseases, rheumatoid diseases, viral infections, neurological and psychological pathologies, and cancer. Moreover, the antitumoral activities of CBD have been suggested to be potentially used in combination with chemo- or immunotherapy during cancer. However, clinical results are still lacking, which raises a challenge to apply translational cannabis research to the human immune system.

Effects of cannabidiol on vacuous chewing movements, plasma glucose and oxidative stress indices in rats administered high dose risperidone

Atypical antipsychotics, despite their rapid dissociation from dopamine receptors and reduced tendency to induce oxidative stress, have been associated with difficult-to-manage movement disorders, including tardive dyskinesia (TD). The study set out to investigate the effects of cannabidiol (CBD), a potent antioxidant, on risperidone-induced behavioural and motor disturbances; namely vacuous chewing movements (VCM), and oxidative stress markers (e.g. superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), malondialdehyde (MDA), Nitric oxide (NO), and DPPH (2,2-diphenyl-1-picrylhydrazyl)). Oral risperidone (10 mg/kg) or oral CBD (5 mg/kg) were administered to six experimental groups. While risperidone alone was administered for 28 days, CBD concomitantly or in sequential order with risperidone, was administered for 28 days; and CBD alone was administered for 21 days. Behavioural, motor, and specific biochemical parameters, which included VCM, muscle tone, fasting blood sugar (FBS), and oxidative stress markers were assessed at different time points after the last dose of medication. Oral CBD (5 mg/kg) significantly reduced risperidone-induced elevated FBS when given after the administration of risperidone. Oral CBD also had effects on VCM when administered before risperidone and similarly, attenuated risperidone-induced increased muscle tone. It was also established that concomitant or sequential administration of CBD and risperidone did not have any adverse effects on cognition or locomotion. Both CBD and risperidone increased the activity of antioxidant enzymes and decreased the activity of pro-oxidant enzymes. This study suggests CBD could mitigate metabolic dysregulation and extrapyramidal side effects associated with risperidone without producing cognitive impairments.

Review: Cannabinoids as Medicinals

PURPOSE OF REVIEW

There have been many debates, discussions, and published writings about the therapeutic value of cannabis plant and the hundreds of cannabinoids it contains. Many states and countries have attempted, are attempting, or have already passed bills to allow legal use of cannabinoids, especially cannabidiol (CBD), as medicines to treat a wide range of clinical conditions without having been approved by a regulatory body. Therefore, by using PubMed and Google Scholar databases, we have reviewed published papers during the past 30 years on cannabinoids as medicines and comment on whether there is sufficient clinical evidence from well-designed clinical studies and trials to support the use of CBD or any other cannabinoids as medicines.

RECENT FINDINGS

Current research shows that CBD and other cannabinoids currently are not ready for formal indications as medicines to treat a wide range of clinical conditions as promoted except for several exceptions including limited use of CBD for treating two rare forms of epilepsy in young children and CBD in combination with THC for treating multiple-sclerosis-associated spasticity.

SUMMARY

Research indicates that CBD and several other cannabinoids have potential to treat multiple clinical conditions, but more preclinical, and clinical studies and clinical trials, which follow regulatory guidelines, are needed to formally recommend CBD and other cannabinoids as medicines.

Review: Cannabinoids as Medicinals

Purpose of review

There have been many debates, discussions, and published writings about the therapeutic value of cannabis plant and the hundreds of cannabinoids it contains. Many states and countries have attempted, are attempting, or have already passed bills to allow legal use of cannabinoids, especially cannabidiol (CBD), as medicines to treat a wide range of clinical conditions without having been approved by a regulatory body. Therefore, by using PubMed and Google Scholar databases, we have reviewed published papers during the past 30 years on cannabinoids as medicines and comment on whether there is sufficient clinical evidence from well-designed clinical studies and trials to support the use of CBD or any other cannabinoids as medicines.

Recent findings

Current research shows that CBD and other cannabinoids currently are not ready for formal indications as medicines to treat a wide range of clinical conditions as promoted except for several exceptions including limited use of CBD for treating two rare forms of epilepsy in young children and CBD in combination with THC for treating multiple-sclerosis-associated spasticity.

Summary

Research indicates that CBD and several other cannabinoids have potential to treat multiple clinical conditions, but more preclinical, and clinical studies and clinical trials, which follow regulatory guidelines, are needed to formally recommend CBD and other cannabinoids as medicines.

Cannabidiol (CBD) drives sex-dependent impairments in omission, but has no effect on reinforcer devaluation

Habits are inflexible behaviors that persist despite changes in outcome value. While habits allow for efficient responding, neuropsychiatric diseases such as drug addiction and obsessive-compulsive disorder are characterized by overreliance on habits. Recently, the commercially popular drug cannabidiol (CBD) has emerged as a potential treatment for addictive behaviors, though it is not entirely clear how it exerts this therapeutic effect. As brain endocannabinoids play a key role in habit formation, we sought to determine how CBD modifies goal-directed behaviors and habit formation. To explore this, mice were administered CBD (20mg/kg i.p.) or vehicle as a control and trained on random interval (RI30/60) or random ratio (RR10/20) schedules designed to elicit habitual or goal-directed lever pressing, respectively. Mice were tested for habitual responding using probe trials following reinforcer-specific devaluation as well as omission trials, where mice had to withhold responding to earn rewards. We found that while CBD had little effect on operant behaviors or reward devaluation, CBD inhibited goal-directed behavior in a sex-specific and contextdependent manner during the omission task. Beyond drug treatment, we found an effect of sex throughout training, reward devaluation, and omission. This work provides evidence that CBD has no effect on habit formation in a reward devaluation paradigm. However, the omission results suggest that CBD may slow learning of novel actionoutcome contingencies or decrease goal-directed behavior. This work calls for further examination of sex-dependent outcomes of CBD treatment and highlights the importance of investigating sex effects in habit-related experiments.

Medical cannabis and cannabidiol: A new harvest for Malawi

In February 2020 parliament passed the Cannabis Regulation Bill (2020) which regulates the cultivation and production of industrial hemp and medical cannabis. The country will only fully benefit from this development if the medical and scientific community can take the lead in enabling the country to exploit the plant's potential to help address some of our economic and public health challenges. This special communication provides some basic information on cannabis and discusses its history and medical uses. Cannabidiol (CBD) has emerged as one of the most important cannabis-derived phytochemicals and has formed the basis for the growth of the medical cannabis industry. The scientific data on the mechanisms of the effects of CBD on the human neuroendocrine-immune network is reviewed and the first effective cannabis-based FDA-approved treatment for epilepsy discussed. Some clinical research that is being done on the antipsychotic and neuroprotective properties of CBD is also reviewed. A case is made for the potential of CBD as a neuroprotective adjunctive therapy for the prevention of neuropsychological sequelae associated with complicated malaria. The safety profile of CBD is reviewed and finally, the potential importance of the re-medicalization of cannabis-based therapies for the broader field of phytomedicine is pointed out.

Acute effects of Δ9-tetrahydrocannabinol and cannabidiol on auditory mismatch negativity

RATIONALE

Mismatch negativity (MMN) is a candidate endophenotype for schizophrenia subserved by N-methyl-D-aspartate receptor (NMDAR) function and there is increasing evidence that prolonged cannabis use adversely affects MMN generation. Few human studies have investigated the acute effects of cannabinoids on brain-based biomarkers of NMDAR function and synaptic plasticity.

OBJECTIVES

The current study investigated the acute effects of Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD) alone and in combination on the mismatch negativity (MMN).

METHODS

In a randomised, double-blind, crossover placebo-controlled study, 18 frequent and 18 less-frequent cannabis users underwent 5 randomised drug sessions administered via vaporiser: (1) placebo; (2) THC 8 mg; (3) CBD 400 mg; (4) THC 8 mg + CBD 4 mg [THC + CBD_low]; (5) THC 12 mg + CBD 400 mg [THC + CBD_high]. Participants completed a multifeature MMN auditory oddball paradigm with duration, frequency and intensity deviants (6% each).

RESULTS

Relative to placebo, both THC and CBD were observed to increase duration and intensity MMN amplitude in less-frequent users, and THC also increased frequency MMN in this group. The addition of low-dose CBD added to THC attenuated the effect of THC on duration and intensity MMN amplitude in less-frequent users. The same pattern of effects was observed following high-dose CBD added to THC on duration and frequency MMN in frequent users.

CONCLUSIONS

The pattern of effects following CBD combined with THC on MMN may be subserved by different underlying neurobiological interactions within the endocannabinoid system that vary as a function of prior cannabis exposure. These results highlight the complex interplay between the acute effects of exogenous cannabinoids and NMDAR function. Further research is needed to determine how this process normalises after the acute effects dissipate and following repeated acute exposure.

A scoping review of the use of cannabidiol in psychiatric disorders

Cannabidiol (CBD) has become a fast-growing avenue for research in psychiatry, and clinicians are challenged with understanding the implications of CBD for treating mental health disorders. The goal of this review is to serve as a guide for mental health professionals by providing an overview of CBD and a synthesis the current evidence within major psychiatric disorders. PubMed and PsycINFO were searched for articles containing the terms "cannabidiol" in addition to major psychiatric disorders and symptoms, yielding 2952 articles. Only randomized controlled trials or within-subject studies investigating CBD as a treatment option for psychiatric disorders (N = 16) were included in the review. Studies were reviewed for psychotic disorders (n = 6), anxiety disorders (n = 3), substance use disorders (tobacco n = 3, cannabis n = 2, opioid n = 1), and insomnia (n = 1). There were no published studies that met inclusion criteria for alcohol or stimulant use disorder, PTSD, ADHD, autism spectrum disorder, or mood disorders. Synthesis of the CBD literature indicates it is generally safe and well tolerated. The most promising preliminary findings are related to the use of CBD in psychotic symptoms and anxiety. There is currently not enough high-quality evidence to suggest the clinical use of CBD for any psychiatric disorder.

European Psychiatric Association guidance on treatment of cognitive impairment in schizophrenia

Background

Although cognitive impairment is a core symptom of schizophrenia related to poorer outcomes in different functional domains, it still remains a major therapeutic challenge. To date, no comprehensive treatment guidelines for cognitive impairment in schizophrenia are implemented.

Methods

The aim of the present guidance paper is to provide a comprehensive meta-review of the current available evidence-based treatments for cognitive impairment in schizophrenia. The guidance is structured into three sections: pharmacological treatment, psychosocial interventions, and somatic treatments.

Results

Based on the reviewed evidence, this European Psychiatric Association guidance recommends an appropriate pharmacological management as a fundamental starting point in the treatment of cognitive impairment in schizophrenia. In particular, second-generation antipsychotics are recommended for their favorable cognitive profile compared to first-generation antipsychotics, although no clear superiority of a single second-generation antipsychotic has currently been found. Anticholinergic and benzodiazepine burdens should be kept to a minimum, considering the negative impact on cognitive functioning. Among psychosocial interventions, cognitive remediation and physical exercise are recommended for the treatment of cognitive impairment in schizophrenia. Noninvasive brain stimulation techniques could be taken into account as add-on therapy.

Conclusions

Overall, there is definitive progress in the field, but further research is needed to develop specific treatments for cognitive impairment in schizophrenia. The dissemination of this guidance paper may promote the development of shared guidelines concerning the treatment of cognitive functions in schizophrenia, with the purpose to improve the quality of care and to achieve recovery in this population.

Antipsychotic Drug Development: From Historical Evidence to Fresh Perspectives

Schizophrenia is a complex disorder of varied etiology, manifesting symptoms that can differ between patients and change throughout an individual's lifespan. Antipsychotic drugs have evolved through first (e.g., haloperidol), second (olanzapine and clozapine) and a possible third (aripiprazole) generation of drugs in an attempt to improve efficacy and tolerability, with minimal side-effects. Despite robust scientific efforts over the past 70 years, there remains a need to develop drugs with greater efficacy, particularly in relation to the negative and cognitive symptoms of schizophrenia, addressing treatment resistance, with a lower side-effects profile compared to existing antipsychotic drugs. Identifying and investigating novel therapeutic targets remains an important component of future antipsychotic drug discovery; however, mounting evidence demonstrates neurobiological, neuroanatomical and functional heterogeneity in cohorts of individuals with schizophrenia. This presents an opportunity to refresh the approach to drug trials to a more targeted strategy. By increasing understanding of the basic science and pharmacological mechanisms underlying the potential antipsychotic efficacy of novel therapeutics prior to clinical trials, new drugs may be appropriately directed to a target population of schizophrenia subjects based on the drug mechanisms and correlating biological sub-groupings of patient characteristics. Improving the lives of sub-populations of people with schizophrenia that share common biological characteristics and are likely to be responsive to a particular compound may be more achievable than aiming to treat the complexities of schizophrenia as a homogenous disorder. This approach to clinical trials in antipsychotic research is discussed in the present review.

Progress and Pitfalls in Developing Agents to Treat Neurocognitive Deficits Associated with Schizophrenia

Cognitive impairments associated with schizophrenia (CIAS) represent a central element of the symptomatology of this severe mental disorder. CIAS substantially determine the disease prognosis and hardly, if at all, respond to treatment with currently available antipsychotics. Remarkably, all drugs presently approved for the treatment of schizophrenia are, to varying degrees, dopamine D₂/D₃ receptor blockers. In turn, rapidly growing evidence suggests the immense significance of systems other than the dopaminergic system in the genesis of CIAS. Accordingly, current efforts addressing the unmet needs of patients with schizophrenia are primarily based on interventions in other non-dopaminergic systems. In this review article, we provide a brief overview of the available evidence on the importance of specific systems in the development of CIAS. In addition, we describe the promising targets for the development of new drugs that have been used so far. In doing so, we present the most important candidates that have been investigated in the field of the specific systems in recent years and present a summary of the results available at the time of drafting this review (May 2022), as well as the currently ongoing studies.

Cannabidiol prevents disruptions in sensorimotor gating induced by psychotomimetic drugs that last for 24-h with probable involvement of epigenetic changes in the ventral striatum

Cannabidiol (CBD), a major non-psychotomimetic component of the Cannabis sativa plant, shows therapeutic potential in several psychiatric disorders, including schizophrenia. The molecular mechanisms underlying the antipsychotic-like effects of CBD are not fully understood. Schizophrenia and antipsychotic treatment can modulate DNA methylation in the blood and brain, resulting in altered expression of diverse genes associated with this complex disorder. However, to date, the possible involvement of DNA methylation in the antipsychotic-like effects of CBD has not been investigated. Therefore, this study aimed at evaluating in mice submitted to the prepulse inhibition (PPI) model: i) the effects of a single injection of CBD or clozapine followed by AMPH or MK-801 on PPI and global DNA methylation changes in the ventral striatum and prefrontal cortex (PFC); and ii). if the acute antipsychotic-like effects of CBD would last for 24-h. AMPH (5 mg/kg) and MK-801 (0.5 mg/kg) impaired PPI. CBD (30 and 60 mg/kg), similar to clozapine (5 mg/kg), attenuated AMPH- and MK801-induced PPI disruption. AMPH, but not MK-801, increased global DNA methylation in the ventral striatum, an effect prevented by CBD. CBD and clozapine increased, by themselves, DNA methylation in the prefrontal cortex. The acute effects of CBD (30 or 60 mg/kg) on the PPI impairment induced by AMPH or MK-801 was also detectable 24 h later. Altogether, the results show that CBD induces acute antipsychotic-like effects that last for 24-h. It also modulates DNA methylation in the ventral striatum, suggesting a new potential mechanism for its antipsychotic-like effects.

Efficacy and safety of medical cannabinoids in children: a systematic review and meta-analysis

Despite the increased use of medical cannabinoids, the efficacy and safety of the treatment among children remain uncertain. The objective was to study the efficacy and safety of medical cannabinoids in children. The search included studies through 11-May-2020. Selection criteria included studies evaluating efficacy and safety outcomes of medical cannabinoids (tetrahydrocannabinol, cannabidiol and other cannabis derivatives) versus control in children, independently assessed by two reviewers. Eight studies were included, all of which are randomized controlled trials. Cannabidiol is associated with 50% reduction in seizures rate (Relative Risk (RR) = 1.69, 95% CI [1.20-2.36]) and caregiver global impression of change (Median Estimated difference = (- 1), 95%CI [- 1.39-(- 0.60)]) in Dravet syndrome, compared to placebo. While cannabidiol was associated with a reduction in reported seizure events (RR = 0.59, 95% CI [0.36-0.97]), no association was found in products contained also tetrahydrocannabinol (RR = 1.35, 95% CI [0.46-4.03]). Higher dose of cannabidiol was associated with decreased appetite (RR = 2.40, 95% CI [1.39-4.15]). A qualitative assessment suggests that medical cannabinoids might be associated with adverse mental events. In conclusion, cannabidiol is associated with clinical improvement in Dravet syndrome. However, cannabidiol is also associated with decreased appetite. Adverse mental events were reported as well, however, more research should be performed to assess well this outcome.

Cannabinoids for the treatment of cannabis use disorder: New avenues for reaching and helping youth?

Cannabis use peaks during adolescence and emerging adulthood, and cannabis use disorder (CUD) is associated with a wide range of adverse outcomes. This is particularly pertinent in youth, because the developing brain may be more vulnerable to adverse effects of frequent cannabis use. Combining evidence-based psychosocial interventions with safe and effective pharmacotherapy is a potential avenue to improve youth outcomes, but we lack approved CUD pharmacotherapies. Here, we review new potential avenues for helping youth with CUD, with a particular focus on cannabinoid-based treatments. Evidence from placebo-controlled RCTs suggests synthetic delta-9-tetrahydrocannabinol (THC) decreases withdrawal symptoms, but not cannabis use, in adults with daily cannabis use/CUD, while findings regarding formulations containing THC combined with cannabidiol (CBD) are mixed. Preliminary evidence from two placebo-controlled RCTs in adults with CUD suggests that both Fatty Acid Amide Hydrolase inhibitors and CBD can reduce cannabis use. However, larger trials are needed to strengthen the evidence. Findings from adults point to cannabinoid-based treatments as a potential strategy that should be examined in youth with CUD.

Cannabis, Cannabinoide und Cannabiskonsumstörungen

Keine Droge führt derzeit zu so intensiven, teilweise leidenschaftlich geführten Diskussionen wie Cannabis. Welche gesundheitlichen und sozialen Risiken birgt die Substanz, wenn sie zu Rauschzwecken gebraucht wird? Dieser Beitrag beschreibt die wichtigsten Cannabinoide, das endogene Cannabissystem sowie mögliche kurzund langfristige Risiken. Er zeigt zudem psychotherapeutische Behandlungsoptionen von Cannabismissbrauch und -abhängigkeit auf.

Cannabidiol enhances verbal episodic memory in healthy young participants: A randomized clinical trial

Cannabis contains a multitude of different compounds. One of them, cannabidiol - a non-psychoactive substance - might counteract negative effects of Δ-9-Tetrahydrocannabinol on hippocampus-dependent memory impairment. The aim of the present study was to investigate the effect of vaping cannabidiol on verbal episodic memory in healthy young subjects. We used a double-blind, placebo-controlled, randomized crossover trial in 39 healthy young subjects. Participants received once a single dose of cannabidiol e-liquid (0.25 ml, 5% cannabidiol, 12.5 mg cannabidiol) and once placebo for vaping after learning 15 unrelated nouns. The primary outcome measure was the short delay verbal memory performance (number of correctly free recalled nouns) 20 min after learning. 34 participants (mean age: 22.26 [3.04]) completed all visits and entered analyses (17 received cannabidiol and 17 received placebo first). Cannabidiol enhanced verbal episodic memory performance (placebo: 7.03 [2.34]; cannabidiol 7.71 [2.48]; adjusted group difference 0.68, 95% CI 0.01 to 1.35; R_2β = .028, p = .048). Importantly, we did not detect medication effects on secondary outcome measures attention or working memory performance, suggesting that CBD has no negative impact on these basic cognitive functions. The results are in line with the idea that vaping cannabidiol interacts with the central endocannabinoid system and is capable to modulate memory processes, a phenomenon with possible therapeutic potential. Further studies are needed to investigate optimal dose-response and time-response relationships.

Cannabidiol Attenuates MK-801-Induced Cognitive Symptoms of Schizophrenia in the Passive Avoidance Test in Mice

Schizophrenia is a chronic mental disorder that disturbs feelings and behavior. The symptoms of schizophrenia fall into three categories: positive, negative, and cognitive. Cognitive symptoms are characterized by memory loss or attentional deficits, and are especially difficult to treat. Thus, there is intense research into the development of new treatments for schizophrenia-related responses. One of the possible strategies is connected with cannabidiol (CBD), a cannabinoid compound. This research focuses on the role of CBD in different stages of memory (acquisition, consolidation, retrieval) connected with fear conditioning in the passive avoidance (PA) learning task in mice, as well as in the memory impairment typical of cognitive symptoms of schizophrenia. Memory impairment was provoked by an acute injection of the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (animal model of schizophrenia). Our results revealed that an acute injection of CBD (30 mg/kg; intraperitoneally (i.p.) improved all phases of long-term fear memory in the PA test in mice. Moreover, the acute injection of non-effective doses of CBD (1 or 5 mg/kg; i.p.) attenuated the memory impairment provoked by MK-801 (0.6 mg/kg; i.p.) in the consolidation and retrieval stages of fear memory, but not in the acquisition of memory. The present findings confirm that CBD has a positive influence on memory and learning processes in mice, and reveals that this cannabinoid compound is able to attenuate memory impairment connected with hypofunction of glutamate transmission in a murine model of schizophrenia.

Cannabidiol (CBD) and cognition in epilepsy

Anecdotal reports of the benefits of cannabis and its components in the treatment of epilepsy have been reported for millennia. However, only recently randomized controlled trial data in support of cannabidiol (CBD) became available resulting in its FDA approval for the treatment of seizures and epilepsy. One of the most common and debilitating comorbidities of epilepsy is cognitive impairment. This impairment has a multifactorial etiology including network dysfunction due to seizures, negative cognitive side effects from anti-seizure medications (ASMs), and mood disturbances. Knowing the effects of a particular ASM (either positive or negative) is vital for providers to counsel patients on expected side effects, and may result in choosing a particular regimen over the other if the patient already suffers from significant cognitive deficits. Unlike most other ASMs and other well-studied cannabinoids such as Δ9-tetrahydrocannabinol, CBD has been shown to have additional mechanisms of action (MOA) that result in neuroprotective, anti-inflammatory, anti-oxidant, and neurogenesis effects. These additional MOAs suggest that the use of CBD could lead to other actions including positive effects on cognition that may be independent of seizure control. This targeted review discusses the currently available data on CBD's effects on cognition in epilepsy. First, we review the proposed mechanisms by which CBD could exert effects on cognition. Then, we present the pre-clinical/animal data investigating cognitive effects of CBD in seizure/epilepsy models. Finally, we discuss the available human data, including the studies in people with epilepsy that included cognitive evaluations pre- and on-CBD, and studies investigating if CBD has any effects on brain structure or function in areas pertinent to memory and cognitive functions.

A Review of the Potential Use of Pinene and Linalool as Terpene-Based Medicines for Brain Health: Discovering Novel Therapeutics in the Flavours and Fragrances of Cannabis

"Medicinal cannabis" is defined as the use of cannabis-based products for the treatment of an illness. Investigations of cannabis compounds in psychiatric and neurological illnesses primarily focus on the major cannabinoids, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (Δ9-THC), which are hypothesised to benefit multiple illnesses manifesting cognitive impairment, neurodegeneration and neuro-inflammation, as well as chronic pain, epilepsy and post-traumatic stress disorder, respectively. The cannabis plant contains >500 compounds, including terpenes responsible for the flavour and fragrance profiles of plants. Recently, research has begun providing evidence on the potential use of certain plant-derived terpenes in modern medicine, demonstrating anti-oxidant, anti-inflammatory, and neuroprotective effects of these compounds. This review examined the effects of two key terpenes, pinene and linalool, on parameters relevant to neurological and psychiatric disorders, highlighting gaps in the literature and recommendations for future research into terpene therapeutics. Overall, evidence is mostly limited to preclinical studies and well-designed clinical trials are lacking. Nevertheless, existing data suggests that pinene and linalool are relevant candidates for further investigation as novel medicines for illnesses, including stroke, ischemia, inflammatory and neuropathic pain (including migraine), cognitive impairment (relevant to Alzheimer's disease and ageing), insomnia, anxiety, and depression. Linalool and pinene influence multiple neurotransmitter, inflammatory and neurotrophic signals as well as behaviour, demonstrating psycho-activity (albeit non-intoxicating). Optimising the phytochemical profile of cannabis chemovars to yield therapeutic levels of beneficial terpenes and cannabinoids, such as linalool, pinene and CBD, could present a unique opportunity to discover novel medicines to treat psychiatric and neurological illnesses; however, further research is needed.

Cannabidiol Confers Neuroprotection in Rats in a Model of Transient Global Cerebral Ischemia: Impact of Hippocampal Synaptic Neuroplasticity

Evidence for the clinical use of neuroprotective drugs for the treatment of cerebral ischemia (CI) is still greatly limited. Spatial/temporal disorientation and cognitive dysfunction are among the most prominent long-term sequelae of CI. Cannabidiol (CBD) is a non-psychotomimetic constituent of Cannabis sativa that exerts neuroprotective effects against experimental CI. The present study investigated possible neuroprotective mechanisms of action of CBD on spatial memory impairments that are caused by transient global cerebral ischemia (TGCI) in rats. Hippocampal synaptic plasticity is a fundamental mechanism of learning and memory. Thus, we also evaluated the impact of CBD on neuroplastic changes in the hippocampus after TGCI. Wistar rats were trained to learn an eight-arm aversive radial maze (AvRM) task and underwent either sham or TGCI surgery. The animals received vehicle or 10 mg/kg CBD (i.p.) 30 min before surgery, 3 h after surgery, and then once daily for 14 days. On days 7 and 14, we performed a retention memory test. Another group of rats that received the same pharmacological treatment was tested in the object location test (OLT). Brains were removed and processed to assess neuronal degeneration, synaptic protein levels, and dendritic remodeling in the hippocampus. Cannabidiol treatment attenuated ischemia-induced memory deficits. In rats that were subjected to TGCI, CBD attenuated hippocampal CA1 neurodegeneration and increased brain-derived neurotrophic factor levels. Additionally, CBD protected neurons against the deleterious effects of TGCI on dendritic spine number and the length of dendritic arborization. These results suggest that the neuroprotective effects of CBD against TGCI-induced memory impairments involve changes in synaptic plasticity in the hippocampus.

Cognitive performance and lifetime cannabis use in patients with first-episode schizophrenia spectrum disorder

INTRODUCTION

Cognitive impairment is among the core features of schizophrenia. In a healthy population, the cognitive deficit is often linked with cannabis abuse, and although the same would be expected in patients with schizophrenia, research has presented contradictory results.

METHODS

Participants were patients with first-episode schizophrenia (FES) spectrum disorder who had been lifetime cannabis users (N = 30), FES non-users (N = 53) as well as healthy controls (HC) also divided into cannabis users (N = 20) and non-users (N = 49). All participants underwent an extensive neurocognitive assessment and filled in a cannabis questionnaire, which allowed for a comparison of the four groups on cognitive functioning.

RESULTS

FES patients using cannabis showed less impaired cognitive functioning with the most prominent difference in visual memory compared to FES non-users. However, they differed neither in the clinical assessment of general psychopathology, positive and negative symptoms, nor in medication from the patient's non-users. A comparison of the HC who used cannabis, and those who did not, revealed no sizeable differences in cognitive performance between the groups.

CONCLUSIONS

The results delivered supporting evidence for the trend of superior neurocognitive performance in FES patients with a lifetime history of cannabis use compared to non-using patients.

Role of Cannabidiol in the Therapeutic Intervention for Substance Use Disorders

Drug treatments available for the management of substance use disorders (SUD) present multiple limitations in efficacy, lack of approved treatments or alarming relapse rates. These facts hamper the clinical outcome and the quality of life of the patients supporting the importance to develop new pharmacological agents. Lately, several reports suggest that cannabidiol (CBD) presents beneficial effects relevant for the management of neurological disorders such as epilepsy, multiple sclerosis, Parkinson’s, or Alzheimer’s diseases. Furthermore, there is a large body of evidence pointing out that CBD improves cognition, neurogenesis and presents anxiolytic, antidepressant, antipsychotic, and neuroprotective effects suggesting potential usefulness for the treatment of neuropsychiatric diseases and SUD. Here we review preclinical and clinical reports regarding the effects of CBD on the regulation of the reinforcing, motivational and withdrawal-related effects of different drugs of abuse such as alcohol, opioids (morphine, heroin), cannabinoids, nicotine, and psychostimulants (cocaine, amphetamine). Furthermore, a special section of the review is focused on the neurobiological mechanisms that might be underlying the ‘anti-addictive’ action of CBD through the regulation of dopaminergic, opioidergic, serotonergic, and endocannabinoid systems as well as hippocampal neurogenesis. The multimodal pharmacological profile described for CBD and the specific regulation of addictive behavior-related targets explains, at least in part, its therapeutic effects on the regulation of the reinforcing and motivational properties of different drugs of abuse. Moreover, the remarkable safety profile of CBD, its lack of reinforcing properties and the existence of approved medications containing this compound (Sativex®, Epidiolex®) increased the number of studies suggesting the potential of CBD as a therapeutic intervention for SUD. The rising number of publications with substantial results on the valuable therapeutic innovation of CBD for treating SUD, the undeniable need of new therapeutic agents to improve the clinical outcome of patients with SUD, and the upcoming clinical trials involving CBD endorse the relevance of this review.

What are the informational pathways that shape people's use of cannabidiol for medical purposes?

Background

Cannabidiol (CBD) is commonly used to manage symptoms in conditions and diseases for which there is limited clinical research for its application. How consumers arrive and decide to use CBD for medical treatment, despite lacking clinical evidence, is largely unknown. In this paper, we seek to identify the informational pathways through which consumers arrive at CBD for medical purposes.

Methods

GoFundMe.com campaigns fundraising to purchase CBD between June 2017 and May 2019 were collected using the Crowdfunding for Health Research Portal (CHRP). Product descriptions were thematically analyzed to determine pathways leading to incorporation of CBD into medical treatment. Campaign characteristics such as fundraising ask, funding received, location, campaign title, description, Facebook shares, and number of donors were recorded. Specific medical uses of CBD proposed in campaigns were tabulated.

Results

The study identified 164 crowdfunding campaigns primarily from the USA (n=159), with several from Canada (n=5). The campaigns requested $2,219,284.24 (median, $7000) and raised $610,612.87 (median, $1805) from 6825 donors (median, 26). Many campaigns asked for other treatments or illness-related costs not specific to CBD. The campaigns were shared 42,299 times on Facebook (median, 156 shares). Three informational pathways were identified leading to incorporation of CBD into medical treatment, which were self-directed research (n=149), recommendations from a trusted care provider (n=36), and/or experiential insights shared by someone associated with or influencing the crowdfunders personal network (n=30). The proposed uses of CBD were for cancer (n=96), seizure-inducing diseases/conditions (n=48), other/unspecified (n=6), joint/inflammatory diseases (n=6), mental health disorders (n=3), nervous system diseases (n=3), and autoimmune diseases (n=2).

Conclusions

Our results suggest that consumers crowdfunding come to CBD through internally motivated reasons versus exposure to advertisements or other forms of marketing. Campaign beneficiaries generally had an unmet medical need that other forms of treatment were not satisfying. Then, through one or more of the informational pathways identified, CBD is considered a potential solution.

Cannabis use and hippocampal subfield volumes in males with a first episode of a schizophrenia spectrum disorder and healthy controls

BACKGROUND

Both schizophrenia and cannabis use are associated with structural brain changes. The hippocampus is a region of particular interest due to its role in memory and select cognitive functions, impairment of which is a core feature of schizophrenia and has also been observed in substance abuse. This study aimed to explore the effects of recent/current cannabis use on hippocampal subfield volumes in male patients with first-episode schizophrenia spectrum disorders and matched controls.

METHODS

This cross-sectional, case-control study included 63 patients and 58 controls scanned on 3T MRI scanners, with hippocampal segmentation performed using recently validated Freesurfer v6.0 software. Cannabis use status was determined by self and carer report together with urine toxicology screening, and patients were categorised as recent/current users or non-users. We used multivariate analysis of covariance (MANCOVA) with age, scan sequence, scan quality, and total intracranial volume as covariates, with subsequent analysis of variance (ANOVA) to test the effects of diagnosis and cannabis use status on individual hippocampal subfields.

RESULTS

We found a group (patient/control) by cannabis use interaction effect in the subiculum, with decreased volumes observed in the cannabis non-using patients compared to the cannabis using patients, and decreased volumes in the cannabis using controls compared to the cannabis non-using controls.

CONCLUSION

The increased subiculum volume in cannabis using patients compared to cannabis non-using patients raises important questions regarding the pathophysiology of schizophrenia and the role of cannabis use therein.

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.

Binge Drinking, Alone or With Cannabis, During Adolescence Triggers Different Effects on Immediate Visual Memory in Men and Women

Background: This study examines the interaction between a history of binge drinking (BD), alone or with cannabis consumption, and the effects of acute alcohol exposure on immediate visual memory (IVM) (faces memory task, scenes memory task and IVM-IQ) in adolescents of both sexes. Method: Two hundred and ninety adolescents, grouped into refrainers, binge drinkers and subjects with a history of simultaneous BD/Cannabis co-use, received a risk dose of alcohol or a control drink. Results: Consumption Pattern (refrainers vs. binge drinkers vs. BD/Cannabis consumers) was not significant, while Treatment (acute alcohol vs. control drink) was significant in both sexes. Also, male binge drinkers' performance in the faces memory task was poorer than that of refrainers and BD/Cannabis consumers who consumed the control drink. BD/Cannabis consumers performed this task as capably as refrainers. In women, binge drinkers performed better than refrainers in scene memory and IVM-IQ tests when given alcohol, and binge drinkers performed worse than refrainers after consuming the control drink. Conclusions: Acute alcohol consumption worsens IVM. Cannabis exerts a buffering effect in men. A cognitive tolerance effect is observed in women. Exposure during adolescence to alcohol, alone or with cannabis, can trigger different cognitive effects in men and women that could endure into adulthood.

Cognitive and behavioral effects of cannabidiol in patients with treatment-resistant epilepsy

PURPOSE

Therapeutic use of cannabidiol (CBD) in intractable epilepsies has increased considerably over the last ten years. As more evidence for the potentially beneficial effects of CBD on different epilepsy types is emerging, it is important to monitor potential cognitive and behavioral side effects. So far, studies including standardized neuropsychological data in the context of treatment with CBD in epilepsy patients are sparse. The present open-label study examines cognitive and behavioral effects of CBD in children and adults with treatment resistant epilepsy.

METHOD

Thirty-nine patients with treatment-resistant epilepsy completed the study protocol, i.e. they were tested at baseline (T0) and after three months of CBD treatment (T1). Patients completed standardized neuropsychological tests on memory, executive functions and attention if they were capable. For cognitively impaired patients who could not complete cognitive tests, caregiver interviews were conducted and caregiver questionnaires completed.

RESULTS

Significant cognitive decline from T0 to T1 was observed on none of the included measures. There was a significant improvement on a measure of selective attention and on a caregiver-rated behavioral measure. More than 89% of all individual test results remained stable or showed reliable improvement from T0 to T1. Cognitive and behavioral changes from T0 to T1 were not significantly correlated with CBD dose. Improvements in short-term/working memory were significantly related to better therapy response.

CONCLUSION

No adverse group-level effects of CBD treatment were detected. On an individual level, most test results remained stable or were improved. Cognitive change was not related to CBD dose. The present results show that, from a cognitive and behavioral point of view, CBD seems to have an encouraging side-effect profile. The results need to be replicated with larger samples.

Subacute cannabidiol alters genome-wide DNA methylation in adult mouse hippocampus

Use of cannabidiol (CBD), the most abundant non-psychoactive compound found in cannabis (Cannabis sativa), has recently increased as a result of widespread availability of CBD-containing products. CBD is FDA-approved for the treatment of epilepsy and exhibits anxiolytic, antipsychotic, prosocial, and other behavioral effects in animal studies and clinical trials, however, the underlying mechanisms governing these phenotypes are still being elucidated. The epigenome, particularly DNA methylation, is responsive to environmental input and can govern persistent patterns of gene regulation affecting phenotype across the life course. In order to understand the epigenomic activity of cannabidiol exposure in the adult brain, 12-week-old male wild-type a/a Agouti viable yellow (A^vy ) mice were exposed to either 20 mg/kg CBD or vehicle daily by oral administration for 14 days. Hippocampal tissue was collected and reduced-representation bisulfite sequencing (RRBS) was performed. Analyses revealed 3,323 differentially methylated loci (DMLs) in CBD-exposed animals with a small skew toward global hypomethylation. Genes for cell adhesion and migration, dendritic spine development, and excitatory postsynaptic potential were found to be enriched in a gene ontology term analysis of DML-containing genes, and disease ontology enrichment revealed an overrepresentation of DMLs in gene sets associated with autism spectrum disorder, schizophrenia, and other phenotypes. These results suggest that the epigenome may be a key substrate for CBD's behavioral effects and provides a wealth of gene regulatory information for further study.

Investigation of the effects of cannabidiol on vacuous chewing movements, locomotion, oxidative stress and blood glucose in rats treated with oral haloperidol

Objectives: Tardive dyskinesia (TD) unlike acute dystonia may be irreversible. This study investigated the effects of oral cannabidiol (CBD) on haloperidol-induced vacuous chewing movement (VCM) model of TD. Methods: There were six experimental groups with different combinations of oral cannabidiol with 5 mg/kg of haloperidol given orally. Behavioural assays and FBS were measured. VCMs were assessed after the last dose of medication. Blood for oxidative stress assays was collected on the 8th day after the administration of the last dose of medication. Results: This study found that CBD co-administration with haloperidol attenuated the VCMs and increased motor tone produced by haloperidol. CBD alone at 5 mg/kg appears to have anxiolytic properties but may not be as effective as haloperidol which exhibited a greater anxiolytic effect at 5 mg/kg. Treatment with CBD alone at 5 mg/kg also appeared to enhance brain DPPH scavenging activity. Conclusions: We confirmed that CBD can ameliorate motor impairments produced by haloperidol. Our data suggest that CBD can be combined with haloperidol to prevent the emergent of extrapyramidal side effects and long-term movement disorders, such as acute dystonic disorder and TD.

Acute effects of naturalistic THC vs. CBD use on recognition memory: a preliminary study

The ratio of ∆9-tetrahydrocannabinol (THC) to cannabidiol (CBD) varies widely across cannabis strains. CBD has opposite effects to THC on a variety of cognitive functions, including acute THC-induced memory impairments. However, additional data are needed, especially under naturalistic conditions with higher potency forms of cannabis, commonly available in legal markets. The goal of this study was to collect preliminary data on the acute effects of different THC:CBD ratios on memory testing in a brief verbal recognition task under naturalistic conditions, using legal-market Colorado dispensary products. Thirty-two regular cannabis users consumed cannabis of differing THC and CBD levels purchased from a dispensary and were assessed via blood draw and a verbal recognition memory test both before (pretest) and after (posttest) ad libitum home administration in a mobile laboratory. Memory accuracy decreased as post-use THC blood levels increased (n = 29), whereas performance showed no relationship to CBD blood levels. When controlling for post-use THC blood levels as a covariate, participants using primarily THC-based strains showed significantly worse memory accuracy post-use, whereas subjects using strains containing both THC and CBD showed no differences between pre- and post-use memory performance. Using a brief and sensitive verbal recognition task, our study demonstrated that naturalistic, acute THC use impairs memory in a dose dependent manner, whereas the combination of CBD and THC was not associated with impairment.

Receptors and Channels Possibly Mediating the Effects of Phytocannabinoids on Seizures and Epilepsy

Epilepsy contributes to approximately 1% of the global disease burden. By affecting especially young children as well as older persons of all social and racial variety, epilepsy is a present disorder worldwide. Currently, only 65% of epileptic patients can be successfully treated with antiepileptic drugs. For this reason, alternative medicine receives more attention. Cannabis has been cultivated for over 6000 years to treat pain and insomnia and used since the 19th century to suppress epileptic seizures. The two best described phytocannabinoids, (−)-trans-Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD) are claimed to have positive effects on different neurological as well as neurodegenerative diseases, including epilepsy. There are different cannabinoids which act through different types of receptors and channels, including the cannabinoid receptor 1 and 2 (CB₁, CB₂), G protein-coupled receptor 55 (GPR55) and 18 (GPR18), opioid receptor µ and δ, transient receptor potential vanilloid type 1 (TRPV1) and 2 (TRPV2), type A γ-aminobutyric acid receptor (GABA_AR) and voltage-gated sodium channels (VGSC). The mechanisms and importance of the interaction between phytocannabinoids and their different sites of action regarding epileptic seizures and their clinical value are described in this review.

Conversion of cannabidiol (CBD) to Δ9-tetrahydrocannabinol (Δ9-THC) during protein precipitations prior to plasma samples analysis by chromatography - Troubles with reliable CBD quantitation when acidic precipitation agents are applied

The growing popularity of supplements containing cannabidiol (CBD), mainly CBD oils, in self-medication of humans and the increased interest in this compound in different preclinical and clinical trials stimulates the development of procedures of CBD analysis in plasma for the study of CBD pharmacology in people and animals or in establishing dose-therapeutic effect relationships of this compound. Preliminary removal of protein by its precipitation from plasma is still one of the willingly applied plasma sample preparation methods in many analytical procedures estimating plasma drug concentration, including CBD. The present paper shows that a significant amount of CBD transforms to Δ9-tetrahydrocannabinol (Δ9-THC) in a hot GC injection system when acidic precipitation agents, such as TFA, TCA, HClO₄, H₂SO₄, ZnSO₄ or CHCl₃, are used for plasma protein precipitation. The transformation degree depends on the temperature of the GC injector, the concentration of the precipitation agent and the incubation time of plasma with the precipitating agent. At the CBD plasma concentration equal to 50 ng/ml, which is approximately the mean level for patients treated for epileptic syndromes, the CBD transformation degree can exceed 20%. For a reliable estimate of CBD in blood plasma, neutral precipitation agents (e.g. ACN, MeOH, acetone) should be used when plasma deproteinization precedes GC analysis. The presented results are important not only for analysts cooperating with pharmacologists and for medicine doctors examining the activity of CBD-containing drugs in the therapeutic process, but also for forensic scientists who may erroneously find innocent people guilty of using marijuana or its preparations.