Use of Cannabidiol for the Treatment of Anxiety: A Short Synthesis of Pre-Clinical and Clinical Evidence

View details for Cannabis and Cannabinoid Research cover image“Anxiety disorders have the highest lifetime prevalence of any mental illness worldwide, leading to high societal costs and economic burden. Current pharmacotherapies for anxiety disorders are associated with adverse effects and low efficacy.

Cannabidiol (CBD) is a constituent of the Cannabis plant, which has potential therapeutic properties for various indications. After the recent legalization of cannabis, CBD has drawn increased attention as a potential treatment, as the majority of existing data suggest it is safe, well tolerated, has few adverse effects, and demonstrates no potential for abuse or dependence in humans.

Pre-clinical research using animal models of innate fear and anxiety-like behaviors have found anxiolytic, antistress, anticompulsive, and panicolytic-like effects of CBD. Preliminary evidence from human trials using both healthy volunteers and individuals with social anxiety disorder, suggests that CBD may have anxiolytic effects.

Although these findings are promising, future research is warranted to determine the efficacy of CBD in other anxiety disorders, establish appropriate doses, and determine its long-term efficacy. The majority of pre-clinical and clinical research has been conducted using males only. Among individuals with anxiety disorders, the prevalence rates, symptomology, and treatment response differ between males and females. Thus, future research should focus on this area due to the lack of research in females and the knowledge gap on sex and gender differences in the effectiveness of CBD as a potential treatment for anxiety.”

https://pubmed.ncbi.nlm.nih.gov/32923656/

“Cannabidiol (CBD) is a constituent of the Cannabis plant, which has potential therapeutic properties across many neuropsychiatric disorders. Overall, existing pre-clinical and clinical evidence supports a possible role for CBD as a novel treatment for anxiety disorders.”

https://www.liebertpub.com/doi/10.1089/can.2019.0052

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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.”

https://pubmed.ncbi.nlm.nih.gov/32921794/

“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.”

https://www.nature.com/articles/s41398-020-0862-2

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Endocannabinoid-Epigenetic Cross-Talk: A Bridge toward Stress Coping

ijms-logo“There is no argument with regard to the physical and psychological stress-related nature of neuropsychiatric disorders. Yet, the mechanisms that facilitate disease onset starting from molecular stress responses are elusive.

Environmental stress challenges individuals’ equilibrium, enhancing homeostatic request in the attempt to steer down arousal-instrumental molecular pathways that underlie hypervigilance and anxiety.

A relevant homeostatic pathway is the endocannabinoid system (ECS).

In this review, we summarize recent discoveries unambiguously listing ECS as a stress coping mechanism.

As stress evokes huge excitatory responses in emotional-relevant limbic areas, the ECS limits glutamate release via 2-arachydonilglycerol (2-AG) stress-induced synthesis and retrograde cannabinoid 1 (CB1)-receptor activation at the synapse. However, ECS shows intrinsic vulnerability as 2-AG overstimulation by chronic stress rapidly leads to CB1-receptor desensitization.

In this review, we emphasize the protective role of 2-AG in stress-response termination and stress resiliency. Interestingly, we discuss ECS regulation with a further nuclear homeostatic system whose nature is exquisitely epigenetic, orchestrated by Lysine Specific Demethylase 1.

We here emphasize a remarkable example of stress-coping network where transcriptional homeostasis subserves synaptic and behavioral adaptation, aiming at reducing psychiatric effects of traumatic experiences.”

https://pubmed.ncbi.nlm.nih.gov/32872402/

https://www.mdpi.com/1422-0067/21/17/6252

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Meet Your Stress Management Professionals: The Endocannabinoids

Trends in Molecular Medicine (@TrendsMolecMed) | Twitter“The endocannabinoid signaling system (ECSS) is altered by exposure to stress and mediates and modulates the effects of stress on the brain.

Considerable preclinical data support critical roles for the endocannabinoids and their target, the CB1 cannabinoid receptor, in the adaptation of the brain to repeated stress exposure.

Chronic stress exposure increases vulnerability to mental illness, so the ECSS has attracted attention as a potential therapeutic target for the prevention and treatment of stress-related psychopathology.

We discuss human genetic studies indicating that the ECSS contributes to risk for mental illness in those exposed to severe stress and trauma early in life, and we explore the potential difficulties in pharmacological manipulation of the ECSS.”

https://pubmed.ncbi.nlm.nih.gov/32868170/

https://www.cell.com/trends/molecular-medicine/fulltext/S1471-4914(20)30177-5?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS1471491420301775%3Fshowall%3Dtrue

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Insights on cannabidiol’s antiallodynic and anxiolytic mechanisms of action in a model of neuropathic pain

PAIN Impact Factor Increase to 6.029 - IASP“Recent studies have shown that cannabidiol (CBD) could have a great therapeutic potential for treating disorders such as chronic pain and anxiety. In the target article, the authors propose that CBD modulates serotonergic transmission and reverses allodynia and anxiety-like behaviour in a rat model of neuropathic pain. Furthermore, this study shows an antinociceptive effect mediated by TRPV1 and partially by 5-HT1A receptors, as well as an anxiolytic effect mediated by 5-HT1A receptors.”

https://pubmed.ncbi.nlm.nih.gov/32766463/

https://journals.lww.com/painrpts/Fulltext/2019/10000/Insights_on_cannabidiol_s_antiallodynic_and.10.aspx

“Cannabidiol modulates serotonergic transmission and reverses both allodynia and anxiety-like behavior in a model of neuropathic pain”  https://pubmed.ncbi.nlm.nih.gov/30157131/

 

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Effects of ∆ 9-tetrahydrocannabinol on aversive memories and anxiety: a review from human studies

Medscape | BMC Psychiatry - Content Listing“Posttraumatic stress disorder (PTSD) may stem from the formation of aberrant and enduring aversive memories. Some PTSD patients have recreationally used Cannabis, probably aiming at relieving their symptomatology.

Here, we seek to review and discuss the effects of THC on aversive memory extinction and anxiety in healthy humans and PTSD patients.

Results: At low doses, THC can enhance the extinction rate and reduce anxiety responses. Both effects involve the activation of cannabinoid type-1 receptors in discrete components of the corticolimbic circuitry, which could couterbalance the low “endocannabinoid tonus” reported in PTSD patients. The advantage of associating CBD with THC to attenuate anxiety while minimizing the potential psychotic or anxiogenic effect produced by high doses of THC has been reported. The effects of THC either alone or combined with CBD on aversive memory reconsolidation, however, are still unknown.

Conclusions: Current evidence from healthy humans and PTSD patients supports the THC value to suppress anxiety and aversive memory expression without producing significant adverse effects if used in low doses or when associated with CBD. Future studies are guaranteed to address open questions related to their dose ratios, administration routes, pharmacokinetic interactions, sex-dependent differences, and prolonged efficacy.”

https://pubmed.ncbi.nlm.nih.gov/32842985/

“Altogether, the findings encourage future controlled studies evaluating the effects of low doses of THC to attenuate aversive/traumatic memory expression in PTSD patients.”

https://bmcpsychiatry.biomedcentral.com/articles/10.1186/s12888-020-02813-8

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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.”

https://pubmed.ncbi.nlm.nih.gov/32579259/

https://onlinelibrary.wiley.com/doi/abs/10.1002/em.22396

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Cannabidiol Disrupts Conditioned Fear Expression and Cannabidiolic Acid Reduces Trauma-Induced Anxiety-Related Behaviour in Mice

Behavioural Pharmacology (journal) - Wikipedia“The major phytocannabinoid cannabidiol (CBD) has anxiolytic properties and lacks tetrahydrocannabinol-like psychoactivity. Cannabidiolic acid (CBDA) is the acidic precursor to CBD, and this compound appears more potent than CBD in animal models of emesis, pain and epilepsy. In this short report, we aimed to examine whether CBDA is more potent than CBD in disrupting expression of conditioned fear and generalised anxiety-related behaviour induced by Pavlovian fear conditioning. Mice underwent fear conditioning and 24 h later were administered CBD and CBDA before testing for fear expression and generalized anxiety-like behaviour. We found that CBD and CBDA had dissociable effects; while CBD but not CBDA disrupted cued fear memory expression, CBDA but not CBD normalized trauma-induced generalized anxiety-related behaviour. Neither phytocannabinoid affected contextual fear expression. Our findings form the basis for future experiments examining whether phytocannabinoids, alone and in combination, are effective in these mouse models of fear and anxiety.”

https://pubmed.ncbi.nlm.nih.gov/32483052/

https://journals.lww.com/behaviouralpharm/Abstract/9000/Cannabidiol_disrupts_conditioned_fear_expression.99176.aspx

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Two-weeks treatment with cannabidiol improves biophysical and behavioral deficits associated with experimental type-1 diabetes.

Neuroscience Letters“The prevalence rates of depression and anxiety are at least two times higher in diabetic patients, increasing morbidity and mortality.

Cannabidiol (CBD) has been identified as a therapeutic agent viable to treat diverse psychiatric disorders. Thus, this study aimed to investigate the effect of CBD treatment (once a day for 14 days starting two weeks after diabetes induction; at doses of 0, 3, 10 or 30 mg/kg, i.p.) on depression- and anxiety-like behaviors associated with experimental diabetes induced by streptozotocin (60 mg/kg; i.p.) in rats.

Levels of plasma insulin, blood glucose, and weight gain were evaluated in all experimental groups, including a positive control group treated with imipramine. The rats were tested in the modified forced swimming test (mFST) and elevated plus maze (EPM) test. Besides, the levels of serotonin (5-HT), noradrenaline (NA) and dopamine (DA) in two emotion-related brain regions, the prefrontal cortex (PFC) and hippocampus (HIP) were evaluated using high-pressure liquid chromatography.

Our results showed that CBD treatment (only at the higher dose of 30 mg/kg) reduced the exaggerated depressive- and anxiogenic-like behaviors of diabetic (DBT) rats, which may be associated with altered 5-HT, NA and/or DA levels observed in the PFC and HIP. Treatment with CBD (higher dose) also induced a significant increase in weight gain and the insulin levels (and consequently reduced glycemia) in DBT rats. The long-term CBD effects gave rise to novel therapeutic strategies to limit the physiological and neurobehavioral deficits in DBT rats.

This approach provided evidence that CBD can be useful for treating psychiatry comorbidities in diabetic patients.”

https://www.ncbi.nlm.nih.gov/pubmed/32360935

“Treatment of diabetic rats with cannabidiol induced antidepressant- and anxiolytic-like behaviors.”

https://www.sciencedirect.com/science/article/abs/pii/S0304394020302901?via%3Dihub

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Chronic Psychosocial Stress Causes Increased Anxiety-Like Behavior and Alters Endocannabinoid Levels in the Brain of C57Bl/6J Mice.

View details for Cannabis and Cannabinoid Research cover image“Chronic stress causes a variety of physiological and behavioral alterations, including social impairments, altered endocrine function, and an increased risk for psychiatric disorders. Thereby, social stress is one of the most effective stressful stimuli among mammals and considered to be one of the major risk factors for the onset and progression of neuropsychiatric diseases.

Although the chronic social defeat stress model has been extensively studied, little is known about the effects of repeated or chronic social defeat stress on the endocannabinoid system (ECS).

The present study aimed to understand the effects of chronic social stress on anxiety behavior and the levels of endocannabinoids (ECs) and two N-acylethanolamines (NAEs) in different brain regions of mice.

 

The current study confirms that the ECS plays an essential role in stress responses, whereby its modulation seems to be brain region dependent.”

https://www.ncbi.nlm.nih.gov/pubmed/32322676

https://www.liebertpub.com/doi/10.1089/can.2019.0041

“Deficiency in endocannabinoid signaling in the nucleus accumbens induced by chronic unpredictable stress.” https://www.ncbi.nlm.nih.gov/pubmed/20664582

“Cannabinoids ameliorate impairments induced by chronic stress to synaptic plasticity and short-term memory.” https://www.ncbi.nlm.nih.gov/pubmed/23426383

“Blunted stress reactivity in chronic cannabis users.”  https://link.springer.com/article/10.1007/s00213-017-4648-z?no-access=true

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