Regulation of DNA Methylation by Cannabidiol and Its Implications for Psychiatry: New Insights from In Vivo and In Silico Models


“Cannabidiol (CBD) is a non-psychotomimetic compound present in cannabis sativa. Many recent studies have indicated that CBD has a promising therapeutic profile for stress-related psychiatric disorders, such as anxiety, schizophrenia and depression. Such a diverse profile has been associated with its complex pharmacology, since CBD can target different neurotransmitter receptors, enzymes, transporters and ion channels. However, the precise contribution of each of those mechanisms for CBD effects is still not yet completely understood. Considering that epigenetic changes make the bridge between gene expression and environment interactions, we review and discuss herein how CBD affects one of the main epigenetic mechanisms associated with the development of stress-related psychiatric disorders: DNA methylation (DNAm). Evidence from in vivo and in silico studies indicate that CBD can regulate the activity of the enzymes responsible for DNAm, due to directly binding to the enzymes and/or by indirectly regulating their activities as a consequence of neurotransmitter-mediated signaling. The implications of this new potential pharmacological target for CBD are discussed in light of its therapeutic and neurodevelopmental effects.”

Incidence and Predictors of Cannabis-Related Poisoning and Mental and Behavioral Disorders among Patients with Medical Cannabis Authorization: A Cohort Study

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“Objective: As medical cannabis use increases in North America, establishing its safety profile is a priority. The objective of this study was to assess rates of emergency department (ED) visits and hospitalizations due to poisoning by cannabis, and cannabis-related mental health disorders among medically authorized cannabis patients in Ontario, Canada, between 2014 and 2017.

Methods: This is a retrospective cohort study of patients who received medical cannabis authorization in Ontario, Canada, using data collected in participating cannabis clinics. Outcomes included ED visit/hospitalization with a main diagnosis code for: cannabis/cannabinoid poisoning; and mental/behavioral disorders due to cannabis use. Cox proportional hazard regressions were utilized to analyze the data.

Results: From 29,153 patients who received medical authorization, 23,091 satisfied the inclusion criteria. During a median follow-up of 240 days, 14 patients visited the ED or were hospitalized for cannabis poisoning-with an incidence rate of 8.06 per 10,000 person-years (95% CI: 4.8-13.6). A total of 26 patients visited the ED or were hospitalized for mental and behavioral disorders due to cannabis use-with an incidence rate of 15.0 per 10,000 person-years (95% CI: 10.2-22.0). Predictors of cannabis-related mental and behavioral disorders include prior substance use disorders, other mental disorders, age, diabetes, and chronic obstructive pulmonary disease.

Conclusions: The results suggest that the incidence of cannabis poisoning or cannabis-related mental and behavioral disorders was low among patients who were authorized to use cannabis for medical care. Identified predictors can help to target patients with potential risk of the studied outcomes.”

Inducing Effects of Illegal Drugs to Improve Mental Health by Self-Regulation Therapy: A Pilot Study

ijerph-logo“This study consists of a brief psychological intervention, which uses Self-Regulation Therapy (SRT, procedure based on suggestion and classical conditioning), to improve coping with stress and emotionality by reproducing the positive effects of illegal drugs: cannabis, cocaine, ecstasy.

Results: SRT was superior to non-intervention for the 4 coping strategies (η2 = 0.829, 0.453, 0.411 and 0.606) and for positive (η2 = 0.371) and negative emotionality (η2 = 0.419). An improvement in scores was evidenced in the follow-up scores compared to the pre-intervention measures.

Conclusions: This study shows for the first time that it is possible to use illegal drugs, considered harmful to public health, to improve young people’s coping capacity and emotionality by reproducing their positive effects with SRT.”

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

Archive of "Frontiers in Psychiatry".“”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.”

“Overall, it appears that the importance of the terpene profile of plants to humans extends further than mere olfactory and gustatory delight. Rather, these compounds have the potential for use as treatments for serious chronic neurological and psychiatric illnesses.”

Cannabis sativa L. as a Natural Drug Meeting the Criteria of a Multitarget Approach to Treatment

ijms-logo“Cannabis sativa L. turned out to be a valuable source of chemical compounds of various structures, showing pharmacological activity. The most important groups of compounds include phytocannabinoids and terpenes.

The pharmacological activity of Cannabis (in epilepsy, sclerosis multiplex (SM), vomiting and nausea, pain, appetite loss, inflammatory bowel diseases (IBDs), Parkinson’s disease, Tourette’s syndrome, schizophrenia, glaucoma, and coronavirus disease 2019 (COVID-19)), which has been proven so far, results from the affinity of these compounds predominantly for the receptors of the endocannabinoid system (the cannabinoid receptor type 1 (CB1), type two (CB2), and the G protein-coupled receptor 55 (GPR55)) but, also, for peroxisome proliferator-activated receptor (PPAR), glycine receptors, serotonin receptors (5-HT), transient receptor potential channels (TRP), and GPR, opioid receptors.

The synergism of action of phytochemicals present in Cannabis sp. raw material is also expressed in their increased bioavailability and penetration through the blood-brain barrier. This review provides an overview of phytochemistry and pharmacology of compounds present in Cannabis extracts in the context of the current knowledge about their synergistic actions and the implications of clinical use in the treatment of selected diseases.”

Cannabidiol: A Potential New Alternative for the Treatment of Anxiety, Depression, and Psychotic Disorders

biomolecules-logo“The potential therapeutic use of some Cannabis sativa plant compounds has been attracting great interest, especially for managing neuropsychiatric disorders due to the relative lack of efficacy of the current treatments.

Numerous studies have been carried out using the main phytocannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD). CBD displays an interesting pharmacological profile without the potential for becoming a drug of abuse, unlike THC.

In this review, we focused on the anxiolytic, antidepressant, and antipsychotic effects of CBD found in animal and human studies. In rodents, results suggest that the effects of CBD depend on the dose, the strain, the administration time course (acute vs. chronic), and the route of administration. In addition, certain key targets have been related with these CBD pharmacological actions, including cannabinoid receptors (CB1r and CB2r), 5-HT1A receptor and neurogenesis factors.

Preliminary clinical trials also support the efficacy of CBD as an anxiolytic, antipsychotic, and antidepressant, and more importantly, a positive risk-benefit profile. These promising results support the development of large-scale studies to further evaluate CBD as a potential new drug for the treatment of these psychiatric disorders.”

A single dose of cannabidiol modulates medial temporal and striatal function during fear processing in people at clinical high risk for psychosis

 Translational Psychiatry“Emotional dysregulation and anxiety are common in people at clinical high risk for psychosis (CHR) and are associated with altered neural responses to emotional stimuli in the striatum and medial temporal lobe.

Using a randomised, double-blind, parallel-group design, 33 CHR patients were randomised to a single oral dose of CBD (600 mg) or placebo. Healthy controls (n = 19) were studied under identical conditions but did not receive any drug. Participants were scanned with functional magnetic resonance imaging (fMRI) during a fearful face-processing paradigm. Activation related to the CHR state and to the effects of CBD was examined using a region-of-interest approach.

During fear processing, CHR participants receiving placebo (n = 15) showed greater activation than controls (n = 19) in the parahippocampal gyrus but less activation in the striatum. Within these regions, activation in the CHR group that received CBD (n = 15) was intermediate between that of the CHR placebo and control groups.

These findings suggest that in CHR patients, CBD modulates brain function in regions implicated in psychosis risk and emotion processing. These findings are similar to those previously evident using a memory paradigm, suggesting that the effects of CBD on medial temporal and striatal function may be task independent.”

“This study is the first to demonstrate that a single dose of CBD modulates activation of the medial temporal cortex and striatum during fear processing in CHR patients. In showing that CBD modulates function of the neural circuitry directly implicated in psychosis onset, these results add to previous evidence that CBD may be a promising novel therapeutic for patients at CHR. Our results also support further investigation of the potential utility of CBD outside of the CHR field in other populations, such as in those with anxiety.”

The Pro-neurogenic Effects of Cannabidiol and Its Potential Therapeutic Implications in Psychiatric Disorders

Archive of "Frontiers in Behavioral Neuroscience". “During the last decades, researchers have investigated the functional relevance of adult hippocampal neurogenesis in normal brain function as well as in the pathogenesis of diverse psychiatric conditions.

Although the underlying mechanisms of newborn neuron differentiation and circuit integration have yet to be fully elucidated, considerable evidence suggests that the endocannabinoid system plays a pivotal role throughout the processes of adult neurogenesis. Thus, synthetic, and natural cannabinoid compounds targeting the endocannabinoid system have been utilized to modulate the proliferation and survival of neural progenitor cells and immature neurons.

Cannabidiol (CBD), a constituent of the Cannabis Sativa plant, interacts with the endocannabinoid system by inhibiting fatty acid amide hydrolase (FAAH) activity (the rate-limiting enzyme for anandamide hydrolysis), allosterically modulating CB1 and CB2 receptors, and activating components of the “extended endocannabinoid system.” Congruently, CBD has shown prominent pro-neurogenic effects, and, unlike Δ9-tetrahydrocannabinol, it has the advantage of being devoid of psychotomimetic effects.

Here, we first review pre-clinical studies supporting the facilitating effects of CBD on adult hippocampal neurogenesis and available data disclosing cannabinoid mechanisms by which CBD can induce neural proliferation and differentiation. We then review the respective implications for its neuroprotective, anxiolytic, anti-depressant, and anti-reward actions.

In conclusion, accumulating evidence reveals that, in rodents, adult neurogenesis is key to understand the behavioral manifestation of symptomatology related to different mental disorders. Hence, understanding how CBD promotes adult neurogenesis in rodents could shed light upon translational therapeutic strategies aimed to ameliorate psychiatric symptomatology dependent on hippocampal function in humans.”

Chronic Cannabidiol Alters Genome-Wide DNA Methylation in Adult Mouse Hippocampus: Epigenetic Implications for Psychiatric Disease

Environmental and Molecular Mutagenesis“Cannabidiol (CBD) is the primary non-psychoactive compound found in cannabis (Cannabis sativa) and an increasingly popular dietary supplement 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 and human studies, 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 chronic cannabidiol exposure in the adult brain, 12-week-old male C57BL/6 mice were exposed to either 20 mg/kg CBD or vehicle daily by oral administration for fourteen 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.”

Altered dopamine D3 receptor gene expression in MAM model of schizophrenia is reversed by peripubertal cannabidiol treatment.

Biochemical Pharmacology“Gestational methylazoxymethanol acetate (MAM) treatment produces offspring with adult phenotype relevant to schizophrenia, including positive- and negative-like symptoms, cognitive deficits, dopaminergic dysfunction, structural and functional abnormalities.

Here we show that adult rats prenatally treated with MAM at gestational day 17 display significant increase in dopamine D3 receptor (D3) mRNA expression in prefrontal cortex (PFC), hippocampus and nucleus accumbens, accompanied by increased expression of dopamine D2 receptor (D2) mRNA exclusively in the PFC. Furthermore, a significant change in the blood perfusion at the level of the circle of Willis and hippocampus, paralleled by the enlargement of lateral ventricles, was also detected by magnetic resonance imaging (MRI) techniques.

Peripubertal treatment with the non-euphoric phytocannabinoid cannabidiol (30 mg/kg) from postnatal day (PND) 19 to PND 39 was able to reverse in MAM exposed rats: i) the up-regulation of the dopamine D3 receptor mRNA (only partially prevented by haloperidol 0.6 mg/kg/day); and ii) the regional blood flow changes in MAM exposed rats. Molecular modelling predicted that cannabidiol could bind preferentially to dopamine D3 receptor, where it may act as a partial agonist according to conformation of ionic-lock, which is higly conserved in GPCRs.

In summary, our results demonstrate that the mRNA expression of both dopamine D2 and D3 receptors is altered in the MAM model; however only the transcript levels of D3 are affected by cannabidiol treatment, likely suggesting that this gene might not only contribute to the schizophrenia symptoms but also represent an unexplored target for the antipsychotic activity of cannabidiol.”