Cannabidiol for the treatment of autism spectrum disorder: hope or hype?

Microbiota-based therapies as novel targets for autism spectrum disorder: A systematic review and meta-analysis

BACKGROUND

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by persistent deficits in social interaction and communication. Emerging evidence suggests that alterations in the gut-brain axis play a key role in the pathophysiology of ASD, and that microbiota-targeted interventions may offer therapeutic benefits. However, no clear consensus has been reached regarding the effectiveness of these strategies in ameliorating behavioral characteristics. This systematic review and meta-analysis (PROSPERO registration ID: CRD42023494067) aimed to evaluate the impact of microbiota-based interventions-including synbiotics, prebiotics, single-strain probiotics, probiotic blends, and fecal microbiota transplantation (FMT)-on behavioral outcomes in individuals with ASD, with particular emphasis on social functioning.

RESULTS

Of the 373 records initially identified, 20 studies met the inclusion criteria, comprising 16 randomized controlled trials and 4 open-label studies. The overall effect size indicated a statistically significant improvement in ASD-related behavioral symptoms following microbiota manipulation (Hedges' g = 0.47; 95 % CI: 0.30-0.64; p < 0.001; I2 = 33.01 %), representing a small but clinically relevant effect. Heterogeneity was classified as moderate. Among the interventions, FMT and probiotic blends yielded the most substantial effects. All major limitations of the current studies were thoroughly addressed and discussed to guide future experimental designs. Additionally, we examined preclinical evidence supporting the involvement of neural, immune, and metabolic pathways in mediating the observed behavioral improvements.

CONCLUSIONS

Our findings support the potential of microbiota-based therapies as a promising and well-tolerated strategy for improving behavioral symptoms in individuals with ASD. FMT and multi-strain probiotic formulations appear particularly effective. Nevertheless, further high-quality randomized controlled trials-especially involving FMT-are urgently needed to validate these results and guide clinical implementation. Thus, these findings provide a critical foundation for future investigations seeking to refine microbiota-based interventions and uncover the underlying mechanisms through which they influence ASD-related behaviors.

Persistent behavioural consequences of chronic adolescent cannabidiol (CBD) in a mouse model with increased susceptibility to Δ9-tetrahydrocannabinol and schizophrenia

Increasingly, the cannabis sativa plant compound cannabidiol (CBD) is used to treat various psychiatric and neurological health conditions which occur in early life or adolescence, including schizophrenia and autism spectrum disorder. However, behavioural effects CBD during adolescence have received limited attention, and the long-lasting behavioural consequences of adolescent CBD treatment are unknown. Thus, this study investigated the effects of chronic CBD in adolescence on behaviours in adulthood, in a mouse model of susceptibility to cannabinoid drugs and schizophrenia, i.e. Neuregulin 1 transmembrane domain heterozygous (Nrg1 TM HET) and wildtype-like (WT) controls. We also assessed if adolescent CBD may affect behavioural responses to acute low dose Δ9-tetrahydrocannabinol (THC) in adulthood. Male Nrg1 TM HET mice and WT controls were administered 30 mg/kg CBD daily intraperitoneally for 3 weeks in adolescence, and then at 5-6 months of age were tested for locomotion, social behaviour, sensorimotor gating and cognition, as well as sensitivity to acute THC-induced behaviours. Adolescent CBD supressed locomotion, exploration, and social behaviours, and reduced anxiety-like behaviours in adult mice. An acute THC challenge in adulthood suppressed social behaviours and acoustic startle in all mice, and adolescent CBD exacerbated THC-induced suppression of acoustic startle in Nrg1 mutant mice. CBD did not alter schizophrenia-relevant behaviours in Nrg1 TM HET mice. To conclude, adolescent CBD exposure had persistent effects on behavioural domains in adulthood including anxiety, locomotion and social behaviours. Furthermore, CBD exposure early in life affected behavioural responses to acute THC in the presence of a risk gene which enhances cannabinoid sensitivity.

Augmentation of Endogenous 2-Arachidonoylglycerol Mitigates Autistic Behaviors of BTBR Mice

The lipid-based endocannabinoid (eCB) system regulates a host of developmental, physiological, and pathological processes in the mammalian brain, and recent studies have suggested that dysfunction of eCB system may contribute to the neuropathology of autism spectrum disorder (ASD). However, specific contributions to ASD-related developmental, cognitive, and behavioral phenotypes remain largely unexplored. The current study was designed to investigate if enhancing eCB signaling by blocking 2-arachidonoylglycerol (2-AG) hydrolase can mitigate ASD-like behaviors in a mouse model, and if such effects are associated with suppression of inflammatory signaling, oxidative stress, or neuronal apoptosis. Intraperitoneal injection of the 2-AG hydrolase monoacylglycerol lipase (MAGL) JZL184 (4, 16, or 40 mg/kg) elevated 2-AG and reversed eCB system metabolic enzymes and receptors expression deficits in BTBR T + ltpr3tf/J (BTBR) mouse model of ASD. Moreover, the hyperactivity, excessive stereotypy, impaired social behavior, and cognitive deficits characteristic of this animal model were significantly improved by JZL184. Concomitantly, JZL184 administration reversed the abnormal pro- and anti-inflammatory cytokine concentrations measured in the hippocampus of BTBR mice. In addition, JZL184 reversed the observed overexpression of pro-apoptotic Bax and underexpression of anti-apoptotic Bcl-2 in BTBR mice and enhanced neuronal numbers in hippocampal CA1 and CA3 regions. We also found that the behavioral test battery influenced eCB concentrations independently of JZL184 treatment. Collectively, these findings suggest that augmenting eCB signaling can mitigate ASD-related phenotypes by suppressing neuroinflammation and neuronal apoptosis.

Nanoemulsions with cannabidiol reduced autistic-like behaviors and reversed decreased hippocampus viable cells and cerebral cortex neuronal death in a prenatal valproic acid rat model

The highly lipophilic nature and low aqueous solubility of cannabidiol (CBD) limit its oral bioavailability, resulting in poor intestinal absorption. To overcome these limitations, we proposed the production of a nanoemulsion with CBD to be included in the therapeutic treatment of autism spectrum disorder. The current study aimed to evaluate the effect of CBD-rich corn oil nanoemulsion treatment in male rats born to females exposed to valproic acid (VPA) during pregnancy on autistic-like behaviors and hippocampal histology. Offspring rats were treated orally twice daily with CBD nanoemulsions at different doses (1 and 2 mg/animal). The endpoints evaluated were anxiety, grooming time, exploratory activity, sociability, the social preference index, and hippocampal and cerebral cortex histology. All formulations were characterized as nanoemulsions and showed a reduced vesicle size (107.6 - 72.6 nm), low PDI (0.290-0.432), negative zeta potential (-40.6 mv), and good stability. Prenatal exposure to VPA increased anxiety and grooming time, and reduced exploratory activity, sociability, and the social preference index in the animals. Furthermore, VPA-exposed animals exhibited elevated neuronal death and a reduction in viable cells in the hippocampus. In conclusion, CBD nanoemulsion treatment reversed autistic-like behaviors, potentially by protecting against hippocampal neuronal death. The highly lipophilic nature and low aqueous solubility of cannabidiol (CBD) limit its oral bioavailability, resulting in poor intestinal absorption. To overcome these limitations, we proposed the production of a nanoemulsion with CBD to be included in the therapeutic treatment of autism spectrum disorder. The current study aimed to evaluate the effect of CBD-rich corn oil nanoemulsion treatment in male rats born to females exposed to valproic acid (VPA) during pregnancy on autistic-like behaviors and hippocampal histology. Offspring rats were treated orally twice daily with CBD nanoemulsions at different doses (1 and 2 mg/animal). The endpoints evaluated were anxiety, grooming time, exploratory activity, sociability, the social preference index, and hippocampal and cerebral cortex histology. All formulations were characterized as nanoemulsions and showed a reduced vesicle size (107.6 - 72.6 nm), low PDI (0.290-0.432), negative zeta potential (-40.6 mv), and good stability. Prenatal exposure to VPA increased anxiety and grooming time, and reduced exploratory activity, sociability, and the social preference index in the animals. Furthermore, VPA-exposed animals exhibited elevated neuronal death and a reduction in viable cells in the hippocampus. In conclusion, CBD nanoemulsion treatment reversed autistic-like behaviors, potentially by protecting against hippocampal neuronal death.

Therapeutic potential of cannabidiol polypharmacology in neuropsychiatric disorders

Cannabidiol (CBD), the primary non-intoxicating compound in cannabis, is currently approved for treating rare, treatment-resistant seizures. Recent preclinical research suggests that CBD's multifaceted mechanisms of action in the brain, which involve multiple molecular targets, underlie its neuroprotective, anti-inflammatory, anxiolytic, and antipsychotic effects. Clinical trials are also exploring CBD's therapeutic potential beyond its current uses. This review focuses on CBD's polypharmacological profile and discusses the latest preclinical and clinical findings regarding its efficacy in neuropsychiatric disorders. Existing evidence suggests that CBD's ability to modulate multiple signaling pathways may benefit neuropsychiatric disorders, and we propose further research areas to clarify its mechanisms, address data gaps, and refine its therapeutic indications.

Acute cannabidiol treatment reverses behavioral impairments induced by embryonic valproic acid exposure in male mice

Cannabidiol (CBD), the major non-psychotomimetic compound of the Cannabis sativa plant, has shown promising effects in addressing various symptoms associated with autism spectrum disorder (ASD). This neurodevelopmental disorder typically impacts cognitive, behavioral, social communication, and motor skills domains. However, effective treatments for the wide range of symptoms associated with the disorder are limited and may trigger undesirable effects. Embryonic exposure to valproic acid (VPA, 500 mg/kg at 12° day embryonic age) in rodents is a consolidated environmental model for studying behavioral and molecular characteristics related to ASD. Therefore, this study aimed to evaluate whether acute CBD could reverse behavioral impairments in adult mice (eight weeks) exposed to VPA in the embryonic period in four distinct trials. In independent groups of animals, the following assays were conducted: I) Pre-Pulse Inhibition Test (PPI), II) Marble Burying, III) Social Interaction, IV) Actimeter Test, and V) Novel Object Recognition Test (NOR). In the PPI paradigm, mice exposed to VPA showed PPI impairment, and CBD (30 and 60 mg/kg) reversed this disruption. CBD (60 mg/kg) respectively decreased the number of buried marbles, improved social interaction time, but failed to reduce stereotyped-like movements in the VPA group. In NOR test CBD at both doses reversed the impairment in index of recognition induced in VPA group. These findings suggest that acute CBD administration can ameliorate behavioral impairments associated with ASD in a well-established animal model for studying this neurodevelopmental disorder.

The Evolving Role of Cannabidiol-Rich Cannabis in People with Autism Spectrum Disorder: A Systematic Review

Autism spectrum disorder (ASD) is a neurological disease and lifelong condition. The treatment gap in ASD has led to growing interest in alternative therapies, particularly in phytocannabinoids, which are naturally present in Cannabis sativa. Studies indicate that treatment with cannabidiol (CBD)-rich cannabis may possess the potential to improve fundamental ASD symptoms as well as comorbid symptoms. This systematic review aims to assess the safety and efficacy of CBD-rich cannabis in alleviating the symptoms of ASD in both children and adults, addressing the treatment gap and growing interest in CBD as an alternative treatment. A comprehensive literature search was conducted in February 2024 using the PUBMED and Scopus databases while following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search focused on studies from 2020 onward involving human populations diagnosed with ASD and treated with CBD. Four studies met the inclusion criteria and were analyzed. The review included 353 participants with ASD from studies conducted in Israel, Turkey, and Brazil. The studies varied in design, sample size, dose, and treatment duration. Dosages of CBD were often combined with trace amounts of THC. Improvements were noted in behavioral symptoms, social responsiveness, and communication, but cognitive benefits were less consistent. Adverse effects ranged in severity. Mild effects such as somnolence and decreased appetite were common, while more concerning effects, including increased aggression, led to some cases of treatment discontinuation. CBD-rich cannabis shows promise in improving behavioral symptoms associated with ASD. However, variations in study designs, dosages, and outcome measures highlight the need for standardized assessment tools and further research to understand pharmacological interactions and optimize treatment protocols. Despite the mild adverse effects observed, larger, well-controlled trials are necessary to establish comprehensive safety and efficacy profiles.

Therapeutic potential of CBD in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by persistent deficits in social communication and interaction, as well as restricted and repetitive patterns of behavior. Despite extensive research, effective pharmacological interventions for ASD remain limited. Cannabidiol (CBD), a non-psychotomimetic compound of the Cannabis sativa plant, has potential therapeutic effects on several neurological and psychiatric disorders. CBD interacts with the endocannabinoid system, a complex cell-signaling system that plays a crucial role in regulating various physiological processes, maintaining homeostasis, participating in social and behavioral processing, and neuronal development and maturation with great relevance to ASD. Furthermore, preliminary findings from clinical trials indicate that CBD may have a modulatory effect on specific ASD symptoms and comorbidities in humans. Interestingly, emerging evidence suggests that CBD may influence the gut microbiota, with implications for the bidirectional communication between the gut and the central nervous system. CBD is a safe drug with low induction of side effects. As it has a multi-target pharmacological profile, it becomes a candidate compound for treating the central symptoms and comorbidities of ASD.

Cannabidiol attenuates seizure susceptibility and behavioural deficits in adult CDKL5R59X knock-in mice

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is caused by a loss-of-function mutation in CDKL5 gene, encoding a serine-threonine kinase highly expressed in the brain. CDD manifests with early-onset epilepsy, autism, motor impairment and severe intellectual disability. While there are no known treatments for CDD, the use of cannabidiol has recently been introduced into clinical practice for neurodevelopmental disorders. Given the increased clinical utilization of cannabidiol, we examined its efficacy in the CDKL5R59X knock-in (R59X) mice, a CDD model based on a human mutation that exhibits both lifelong seizure susceptibility and behavioural deficits. We found that cannabidiol pre-treatment rescued the increased seizure susceptibility in response to the chemoconvulsant pentylenetetrazol (PTZ), attenuated working memory and long-term memory impairments, and rescued social deficits in adult R59X mice. To elucidate a potential mechanism, we compared the developmental hippocampal and cortical expression of common endocannabinoid (eCB) targets in R59X mice and their wild-type littermates, including cannabinoid type 1 receptor (CB1R), transient receptor potential vanilloid type 1 (TRPV1) and 2 (TRPV2), G-coupled protein receptor 55 (GPR55) and adenosine receptor 1 (A1R). Many of these eCB targets were developmentally regulated in both R59X and wild-type mice. In addition, adult R59X mice demonstrated significantly decreased expression of CB1R and TRPV1 in the hippocampus, and TRPV2 in the cortex, while TRPV1 was increased in the cortex. These findings support the potential for dysregulation of eCB signalling as a plausible mechanism and therapeutic target in CDD, given the efficacy of cannabidiol to attenuate hyperexcitability and behavioural deficits in this disorder.

Cannabidiol is a behavioral modulator in BTBR mouse model of idiopathic autism

Introduction

The prevalence of Autism Spectrum Disorder (ASD) has drastically risen over the last two decades and is currently estimated to affect 1 in 36 children in the U.S., according to the center for disease control (CDC). This heterogenous neurodevelopmental disorder is characterized by impaired social interactions, communication deficits, and repetitive behaviors plus restricted interest. Autistic individuals also commonly present with a myriad of comorbidities, such as attention deficit hyperactivity disorder, anxiety, and seizures. To date, a pharmacological intervention for the treatment of core autistic symptoms has not been identified. Cannabidiol (CBD), the major nonpsychoactive constituent of Cannabis sativa, is suggested to have multiple therapeutic applications, but its effect(s) on idiopathic autism is unknown. We hypothesized that CBD will effectively attenuate the autism-like behaviors and autism-associated comorbid behaviors in BTBR T+Itpr3tf/J (BTBR) mice, an established mouse model of idiopathic ASD.

Methods

Male BTBR mice were injected intraperitoneally with either vehicle, 20 mg/kg CBD or 50 mg/kg CBD daily for two weeks beginning at postnatal day 21 ± 3. On the final treatment day, a battery of behavioral assays were used to evaluate the effects of CBD on the BTBR mice, as compared to age-matched, vehicle-treated C57BL/6 J mice.

Results

High dose (50 mg/kg) CBD treatment attenuated the elevated repetitive self-grooming behavior and hyperlocomotion in BTBR mice. The social deficits exhibited by the control BTBR mice were rescued by the 20 mg/kg CBD treatment.

Discussion

Our data indicate that different doses for CBD are needed for treating specific ASD-like behaviors. Together, our results suggest that CBD may be an effective drug to ameliorate repetitive/restricted behaviors, social deficits, and autism-associated hyperactivity.

Cannabidiol and its Potential Evidence-Based Psychiatric Benefits - A Critical Review

The endocannabinoid system shows promise as a novel target for treating psychiatric conditions. Cannabidiol (CBD), a naturally occurring cannabinoid, has been investigated in several psychiatric conditions, with diverse effects and an excellent safety profile compared to standard treatments. Even though the body of evidence from randomised clinical trials is growing, it remains relatively limited in most indications. This review comprises a comprehensive literature search to identify clinical studies on the effects of CBD in psychiatric conditions. The literature search included case studies, case reports, observational studies, and RCTs published in English before July 27, 2023, excluding studies involving nabiximols or cannabis extracts containing CBD and ∆9-tetrahydrocannabinol. Completed studies were considered, and all authors independently assessed relevant publications.Of the 150 articles identified, 54 publications were included, covering the effects of CBD on healthy subjects and various psychiatric conditions, such as schizophrenia, substance use disorders (SUDs), anxiety, post-traumatic stress disorder (PTSD), and autism spectrum disorders. No clinical studies have been published for other potential indications, such as alcohol use disorder, borderline personality disorder, depression, dementia, and attention-deficit/hyperactivity disorder. This critical review highlights that CBD can potentially ameliorate certain psychiatric conditions, including schizophrenia, SUDs, and PTSD. However, more controlled studies and clinical trials, particularly investigating the mid- to long-term use of CBD, are required to conclusively establish its efficacy and safety in treating these conditions. The complex effects of CBD on neural activity patterns, likely by impacting the endocannabinoid system, warrant further research to reveal its therapeutic potential in psychiatry.

Cannabidiol and positive effects on object recognition memory in an in vivo model of Fragile X Syndrome: Obligatory role of hippocampal GPR55 receptors

Cannabidiol (CBD), a non-psychotomimetic constituent of Cannabis sativa, has been recently approved for epileptic syndromes often associated with Autism spectrum disorder (ASD). However, the putative efficacy and mechanism of action of CBD in patients suffering from ASD and related comorbidities remain debated, especially because of the complex pharmacology of CBD. We used pharmacological, immunohistochemical and biochemical approaches to investigate the effects and mechanisms of action of CBD in the recently validated Fmr1-Δexon 8 rat model of ASD, that is also a model of Fragile X Syndrome (FXS), the leading monogenic cause of autism. CBD rescued the cognitive deficits displayed by juvenile Fmr1-Δexon 8 animals, without inducing tolerance after repeated administration. Blockade of CA1 hippocampal GPR55 receptors prevented the beneficial effect of both CBD and the fatty acid amide hydrolase (FAAH) inhibitor URB597 in the short-term recognition memory deficits displayed by Fmr1-Δexon 8 rats. Thus, CBD may exert its beneficial effects through CA1 hippocampal GPR55 receptors. Docking analysis further confirmed that the mechanism of action of CBD might involve competition for brain fatty acid binding proteins (FABPs) that deliver anandamide and related bioactive lipids to their catabolic enzyme FAAH. These findings demonstrate that CBD reduced cognitive deficits in a rat model of FXS and provide initial mechanistic insights into its therapeutic potential in neurodevelopmental disorders.

Highly purified cannabidiol in the treatment of drug-resistant epilepsies: A real-life impact on seizure frequency, quality of life, behavior, and sleep patterns from a single Italian center

Seizure frequency in treatment-resistant epilepsies seems to be decreased by cannabidiol (CBD), but contrasting data are available on its effect on sleep, behavior, and quality of life (QoL), and no data is reported on its effect on parental stress in patients with epilepsy (PWE). Thus, we conducted a retrospective study on a cohort of children and adults with drug-resistant epilepsy (DRE) who had been treated with highly purified, pharmaceutical-grade CBD to evaluate its effects on seizure frequency, QoL, behavior, parental stress, and sleep. Eighteen patients (12 adults and 6 children) were included in the cohort and followed for a median of 9 months. At the last follow-up (Tn), nine patients (50%) were considered CBD responders with at least a 50% decrease in seizure frequency. No serious adverse effects were found. No statistically significant differences were found concerning sleep, including daytime sleepiness, and no statistically significant effect was found on parental stress at Tn. An improvement was found for social interaction in quality of life (p < 0.05) for all patients. Our results demonstrate that CBD is a safe and effective antiseizure medication (ASM). CBD doesn't seem to affect sleep measures in adults and children or worsen daytime sleepiness. However, CBD improves specific QoL measures, which could indicate a possible use of CBD for other childhood disabilities. No impact of CBD was seen on parental stress, which could possibly be due to the limited follow-up or could mean that parental stress is not dependent on seizure frequency.

The Main Therapeutic Applications of Cannabidiol (CBD) and Its Potential Effects on Aging with Respect to Alzheimer's Disease

The use of cannabinoids (substances contained specifically in hemp plants) for therapeutic purposes has received increased attention in recent years. Presently, attention is paid to two main cannabinoids: delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). With respect to the psychotropic effects and dependence potential of THC (though it is very mild), its use is associated with certain restrictions, and thus the therapeutic properties of CBD are frequently emphasized because there are no limitations associated with the risk of dependence. Therefore, this review covers the main pharmacodynamic and pharmacokinetic features of CBD (including characteristics of endocannabinoidome) with respect to its possible beneficial effects on selected diseases in clinical practice. A substantial part of the text deals with the main effects of CBD on aging, including Alzheimer's disease and related underlying mechanisms.

Parental Perceptions and Usage of Unlicensed Cannabidiol Products in Children With Anxiety and Neurodevelopmental Disorders

OBJECTIVE

Data evaluating the use of unlicensed cannabidiol (CBD) products for the treatment of -symptoms associated with anxiety and neurodevelopmental disorders in children are limited despite increasing -product availability. The objectives of this study are to quantify the usage of unlicensed CBD products among pediatric patients diagnosed with anxiety and neurodevelopmental disorders and compare the -perceptions of CBD between parents who administer a CBD product to a child and parents who do not.

METHODS

A survey containing 31 items was designed after pretesting with pediatric health care professionals. The refined survey was distributed using Qualtrics Panels to a representative sample of US parents of a child 7 to 18 years of age diagnosed with attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and/or generalized anxiety disorder (GAD). Responses were analyzed with descriptive -statistics and compared using a χ2 or Mann-Whitney U test.

RESULTS

Of the 518 completed surveys, 162 parents (31.3%) reported the administration of an unlicensed CBD product to a child with ADHD, ASD, and/or GAD. The highest prevalence of use was found in the West geographic region and among children diagnosed with GAD or with 2 or more diagnoses (i.e., ADHD, ASD, GAD). Parents who administered CBD products had more positive views of product safety and higher -perceived community support for usage.

CONCLUSIONS

Nearly one-third of parents have administered an unlicensed CBD product to a child with ADHD, ASD, and GAD. Health care providers should assess pediatric patients for CBD use and be prepared to engage parents in conversations regarding the safety of these products.

The therapeutic potential of purified cannabidiol

The use of cannabidiol (CBD) for therapeutic purposes is receiving considerable attention, with speculation that CBD can be useful in a wide range of conditions. Only one product, a purified form of plant-derived CBD in solution (Epidiolex), is approved for the treatment of seizures in patients with Lennox-Gastaut syndrome, Dravet syndrome, or tuberous sclerosis complex. Appraisal of the therapeutic evidence base for CBD is complicated by the fact that CBD products sometimes have additional phytochemicals (like tetrahydrocannabinol (THC)) present, which can make the identification of the active pharmaceutical ingredient (API) in positive studies difficult. The aim of the present review is to critically review clinical studies using purified CBD products only, in order to establish the upcoming indications for which purified CBD might be beneficial. The areas in which there is the most clinical evidence to support the use of CBD are in the treatment of anxiety (positive data in 7 uncontrolled studies and 17 randomised controlled trials (RCTs)), psychosis and schizophrenia (positive data in 1 uncontrolled study and 8 RCTs), PTSD (positive data in 2 uncontrolled studies and 4 RCTs) and substance abuse (positive data in 2 uncontrolled studies and 3 RCTs). Seven uncontrolled studies support the use of CBD to improve sleep quality, but this has only been verified in one small RCT. Limited evidence supports the use of CBD for the treatment of Parkinson's (3 positive uncontrolled studies and 2 positive RCTs), autism (3 positive RCTs), smoking cessation (2 positive RCTs), graft-versus-host disease and intestinal permeability (1 positive RCT each). Current RCT evidence does not support the use of purified oral CBD in pain (at least as an acute analgesic) or for the treatment of COVID symptoms, cancer, Huntington's or type 2 diabetes. In conclusion, published clinical evidence does support the use of purified CBD in multiple indications beyond epilepsy. However, the evidence base is limited by the number of trials only investigating the acute effects of CBD, testing CBD in healthy volunteers, or in very small patient numbers. Large confirmatory phase 3 trials are required in all indications.

Implications of the endocannabinoid system and the therapeutic action of cannabinoids in autism spectrum disorder: A literature review

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, onset in early childhood and associated with cognitive, social, behavioral, and sensory impairments. The pathophysiology is still unclear, and it is believed that genetic and environmental factors are fully capable of influencing ASD, especially cell signaling and microglial functions. Furthermore, the endocannabinoid system (ECS) participates in the modulation of various brain processes and is also involved in the pathophysiological mechanisms of this condition. Due to the health and quality of life impacts of autism for the patient and his/her family and the lack of effective medications, the literature has elucidated the possibility that Cannabis phytocannabinoids act favorably on ASD symptoms, probably through the modulation of neurotransmitters, in addition to endogenous ligands derived from arachidonic acid, metabolizing enzymes and even transporters of the membrane. These findings support the notion that there are links between key features of ASD and ECS due to the favorable actions of cannabidiol (CBD) and other cannabinoids on symptoms related to behavioral and cognitive disorders, as well as deficits in communication and social interaction, hyperactivity, anxiety and sleep disorders. Thus, phytocannabinoids emerge as therapeutic alternatives for ASD.