Category Archives: Schizophrenia

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

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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.”

https://pubmed.ncbi.nlm.nih.gov/33228239/

https://www.mdpi.com/2218-273X/10/11/1575

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

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 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

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

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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.”

https://pubmed.ncbi.nlm.nih.gov/32676014/

https://www.frontiersin.org/articles/10.3389/fnbeh.2020.00109/full

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

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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

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

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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.”

https://www.ncbi.nlm.nih.gov/pubmed/32360362

https://www.sciencedirect.com/science/article/abs/pii/S000629522030232X?via%3Dihub

Dosage, Efficacy and Safety of Cannabidiol Administration in Adults: A Systematic Review of Human Trials.

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“Considering data from in vitro and in vivo studies, cannabidiol (CBD) seems to be a promising candidate for the treatment of both somatic and psychiatric disorders.

The aim of this review was to collect dose(s), dosage schemes, efficacy and safety reports of CBD use in adults from clinical studies.

From the controlled trials, we identified anxiolytic effects with acute CBD administration, and therapeutic effects for social anxiety disorder, psychotic disorder and substance use disorders.

There was evidence to support single dose positive effect on social anxiety disorder, short medium-term effects on symptomatic improvement in schizophrenia and lack of effect in the short medium-term on cognitive functioning in psychotic disorders.

Overall, the administration was well tolerated with mild side effects.”

https://www.ncbi.nlm.nih.gov/pubmed/32231748

https://www.jocmr.org/index.php/JOCMR/article/view/4090

Cannabidiol attenuates behavioral changes in a rodent model of schizophrenia through 5-HT1A, but not CB1 and CB2 receptors.

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Pharmacological Research“Preclinical and clinical data indicate that cannabidiol (CBD), a non-psychotomimetic compound from the Cannabis sativa plant, can induce antipsychotic-like effects.

These data suggest that CBD induces antipsychotic-like effects by activating 5-HT1A receptors and indicate that this compound could be an interesting alternative for the treatment of negative and cognitive symptoms of schizophrenia.”

https://www.ncbi.nlm.nih.gov/pubmed/32151683

https://www.sciencedirect.com/science/article/abs/pii/S1043661819315439?via%3Dihub

Cannabidiol as a treatment option for schizophrenia: recent evidence and current studies.

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Image result for current opinion in psychiatry “The most recent studies published or initiated in the last 18 months, investigating cannabidiol in the treatment of symptoms of schizophrenia and related conditions are summarized, including observed tolerability and reported side-effects.

RECENT FINDINGS:

Recent studies focused on patients with sub-acute psychotic syndromes of schizophrenia, clinical high-risk state for psychosis (CHR-P), or frequent cannabis users, as well as cognitive functioning in chronic schizophrenia. There is further, although not consistent evidence for cannabidiol-reducing positive symptoms, but not negative symptoms. Evidence for improvement of cognition was weaker, with one study reporting a worsening. Regarding side effects and tolerability, cannabidiol induced sedation in one study, with the other studies indicating good tolerability, even at high doses.

SUMMARY:

Recent clinical trials added further evidence for an antipsychotic potential of cannabidiol. In general, studies following trial designs as suggested by regulators in schizophrenia are needed in sufficient numbers to clarify the safety and efficacy of cannabidiol herein. In addition, such studies will further elucidate its ability to target specific aspects of the syndrome, such as negative or cognitive symptoms. Furthermore, aiming for an add-on treatment with cannabidiol will require further studies to identify potentially useful or even harmful combinations.”

https://www.ncbi.nlm.nih.gov/pubmed/32073423

https://journals.lww.com/co-psychiatry/Abstract/publishahead/Cannabidiol_as_a_treatment_option_for.99134.aspx

Possible therapeutic applications of cannabis in the neuropsychopharmacology field.

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European Neuropsychopharmacology“Cannabis use induces a plethora of actions on the CNS via its active chemical ingredients, the so-called phytocannabinoids.

These compounds have been frequently associated with the intoxicating properties of cannabis preparations. However, not all phytocannabinoids are psychotropic, and, irrespective of whether they are psychotropic or not, they have also shown numerous therapeutic properties.

These properties are mostly associated with their ability to modulate the activity of an intercellular communication system, the so-called endocannabinoid system, which is highly active in the CNS and has been found altered in many neurological disorders.

Specifically, this includes the neuropsychopharmacology field, with diseases such as schizophrenia and related psychoses, anxiety-related disorders, mood disorders, addiction, sleep disorders, post-traumatic stress disorder, anorexia nervosa and other feeding-related disorders, dementia, epileptic syndromes, as well as autism, fragile X syndrome and other neurodevelopment-related disorders.

Here, we gather, from a pharmacological and biochemical standpoint, the recent advances in the study of the therapeutic relevance of the endocannabinoid system in the CNS, with especial emphasis on the neuropsychopharmacology field. We also illustrate the efforts that are currently being made to investigate at the clinical level the potential therapeutic benefits derived from elevating or inhibiting endocannabinoid signaling in animal models of neuropsychiatric disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/32057592

https://www.sciencedirect.com/science/article/abs/pii/S0924977X20300365?via%3Dihub

Normalization of mediotemporal and prefrontal activity, and mediotemporal-striatal connectivity, may underlie antipsychotic effects of cannabidiol in psychosis.

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 Image result for cambridge university press“Recent evidence suggests that cannabidiol (CBD), a non-intoxicating ingredient present in cannabis extract, has an antipsychotic effect in people with established psychosis. However, the effect of CBD on the neurocognitive mechanisms underlying psychosis is unknown.

METHODS:

Patients with established psychosis on standard antipsychotic treatment were studied on separate days at least one week apart, to investigate the effects of a single dose of orally administered CBD (600 mg) compared to a matched placebo (PLB), using a double-blind, randomized, PLB-controlled, repeated-measures, within-subject cross-over design. Three hours after taking the study drug participants were scanned using a block design functional magnetic resonance imaging (fMRI) paradigm, while performing a verbal paired associate learning task. Fifteen psychosis patients completed both study days, 13 completed both scanning sessions. Nineteen healthy controls (HC) were also scanned using the same fMRI paradigm under identical conditions, but without any drug administration. Effects of CBD on brain activation measured using the blood oxygen level-dependent hemodynamic response fMRI signal were studied in the mediotemporal, prefrontal, and striatal regions of interest.

RESULTS:

Compared to HC, psychosis patients under PLB had altered prefrontal activation during verbal encoding, as well as altered mediotemporal and prefrontal activation and greater mediotemporal-striatal functional connectivity during verbal recall. CBD attenuated dysfunction in these regions such that activation under its influence was intermediate between the PLB condition and HC. CBD also attenuated hippocampal-striatal functional connectivity and caused trend-level symptom reduction in psychosis patients.

CONCLUSIONS:

This suggests that normalization of mediotemporal and prefrontal dysfunction and mediotemporal-striatal functional connectivity may underlie the antipsychotic effects of CBD.”

https://www.ncbi.nlm.nih.gov/pubmed/31994476

https://www.cambridge.org/core/journals/psychological-medicine/article/normalization-of-mediotemporal-and-prefrontal-activity-and-mediotemporalstriatal-connectivity-may-underlie-antipsychotic-effects-of-cannabidiol-in-psychosis/6571F47CE15D05DC50782A7BB7C00A7F