Cannabidiol, a plant-derived compound, is an emerging strategy for treating cognitive impairments: comprehensive review of randomized trials

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“Background: Finding new strategies to treat cognitive disorders is a challenging task. Medication must defeat the blood-brain barrier. Cannabidiol (CBD), a non-intoxicating compound of the cannabis plant, has gained recognition as a nutraceutical for its potential effectiveness in treating anxiety, oxidative stress, convulsions, and inflammation. However, the dose, tolerable upper intake, formulation, administration routes, comorbidities, diet, and demographic factors to reverse cognitive impairments have not been completely explored. Trials using CBD as a primary intervention have been conducted to alleviate cognitive issues. This review evaluates the benefits of CBD supplementation, research design, formulations, and outcomes reported in randomized clinical trials.

Methods: An evidence-based systematic literature review was conducted using PUBMED and the Florida International University Research Library resources. Fourteen randomized trials were selected for review, and their designs and outcomes were compared conceptually and in the form of resume tables.

Results: CBD showed improvement in anxiety and cognitive impairments in 9 out of 16 analyzed trials. However, the variability could be justified due to the diversity of the trial designs, underpowered studies, assayed population, uncontrolled results for comorbidities, medications, severity of drug dependence, compliances, and adherences. Overall, oral single doses of 200 mg-1,500 mg or vaporized 13.75 mg of CBD were shown to be effective at treating anxiety and cognition with a good safety profile and no drug addiction behaviors. Conversely, results that did not have a significant effect on treating cognitive impairments can be explained by various factors such as THC or other abuse drugs masking effect, low dose, and unknown purity of CBD. Furthermore, CBD shows potential properties that can be tested in the future for Alzheimer’s disease.

Conclusion: As medical cannabis becomes more accessible, it is essential to understand whether medication rich in CBD exerts a beneficial effect on cognitive disorders. Our study concludes that CBD is a promising candidate for treating neurocognitive disorders; however, more studies are required to define CBD as a therapeutic candidate for managing cognitive disorders.”

https://pubmed.ncbi.nlm.nih.gov/39323633/

“Cannabidiol (CBD), a phytocannabinoid, is derived from the cannabis plant.”

https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1403147/full

Multi-level therapeutic actions of cannabidiol in ketamine-induced schizophrenia psychopathology in male rats

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“Repeated administration of ketamine (KET) has been used to model schizophrenia-like symptomatology in rodents, but the psychotomimetic neurobiological and neuroanatomical underpinnings remain elusive. In parallel, the unmet need for a better treatment of schizophrenia requires the development of novel therapeutic strategies.

Cannabidiol (CBD), a major non-addictive phytocannabinoid has been linked to antipsychotic effects with unclear mechanistic basis. Therefore, this study aims to clarify the neurobiological substrate of repeated KET administration model and to evaluate CBD’s antipsychotic potential and neurobiological basis.

CBD-treated male rats with and without prior repeated KET administration underwent behavioral analyses, followed by multilevel analysis of different brain areas including dopaminergic and glutamatergic activity, synaptic signaling, as well as electrophysiological recordings for the assessment of corticohippocampal and corticostriatal network activity.

Repeated KET model is characterized by schizophrenia-like symptomatology and alterations in glutamatergic and dopaminergic activity mainly in the PFC and the dorsomedial striatum (DMS), through a bi-directional pattern. These observations are accompanied by glutamatergic/GABAergic deviations paralleled to impaired function of parvalbumin- and cholecystokinin-positive interneurons, indicative of excitation/inhibition (E/I) imbalance.

Moreover, CBD counteracted the schizophrenia-like behavioral phenotype as well as reverted prefrontal abnormalities and ventral hippocampal E/I deficits, while partially modulated dorsostriatal dysregulations.

This study adds novel insights to our understanding of the KET-induced schizophrenia-related brain pathology, as well as the CBD antipsychotic action through a region-specific set of modulations in the corticohippocampal and costicostrtiatal circuitry of KET-induced profile contributing to the development of novel therapeutic strategies focused on the ECS and E/I imbalance restoration.”

https://pubmed.ncbi.nlm.nih.gov/39242923/

https://www.nature.com/articles/s41386-024-01977-1


Occasional cannabis use is associated with higher premorbid functioning and IQ in youth at clinical high-risk (CHR) for psychosis: Parallel findings to psychosis cohorts

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“Background: Neurocognitive deficits have been widely reported in clinical high-risk for psychosis (CHR) populations. Additionally, rates of cannabis use are high among CHR youth and are associated with greater symptom severity. Cannabis use has been sometimes shown to be associated with better neurocognition in more progressed psychosis cohorts, therefore in this study we aimed to determine whether a similar pattern was present in CHR.

Methods: CHR participants ages 12-30 from the North American Prodromal Longitudinal Study (NAPLS-3) (N = 698) were grouped according to: “minimal to no cannabis use” (n = 406), “occasional use” (n = 127), or “frequent use” (n = 165). At baseline, cannabis use groups were compared on neurocognitive tests, clinical, and functional measures. Follow-up analyses were used to model relationships between cannabis use frequency, neurocognition, premorbid, and social functioning.

Results: Occasional cannabis users performed significantly better than other use-groups on measures of IQ, with similar trend-level patterns observed across neurocognitive domains. Occasional cannabis users demonstrated better social, global, and premorbid functioning compared to the other use-groups and less severe symptoms compared to the frequent use group. Follow-up structural equation modeling/path analyses found significant positive associations between premorbid functioning, social functioning, and IQ, which in turn was associated with occasional cannabis use frequency.

Discussion: Better premorbid functioning positively predicts both better social functioning and higher IQ which in turn is associated with a moderate cannabis use pattern in CHR, similar to reports in first-episode and chronic psychosis samples. Better premorbid functioning likely represents a protective factor in the CHR population and predicts a better functional outcome.”

https://pubmed.ncbi.nlm.nih.gov/39084107/

“This study contributed to emerging studies in CHR and provided parallel findings to existing evidence from both FEP and chronic psychosis populations of better neurocognitive performance among those who use cannabis”

https://www.sciencedirect.com/science/article/pii/S0920996424003384?via%3Dihub

Investigating Cannabidiol’s Potential as a Supplementary Treatment for Schizophrenia: A Narrative Review

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“Schizophrenia presents a complex mental health challenge, often inadequately addressed by existing antipsychotic treatments, leading to persistent symptoms and adverse effects. Hence, developing alternative therapeutic approaches is crucial.

Cannabidiol (CBD), a nonpsychoactive compound in Cannabis sativa, has been extensively explored for its therapeutic potential in treating psychiatric disorders, including schizophrenia. CBD exhibits antipsychotic, anxiolytic, and neuroprotective effects. However, distinguishing the individual effects of CBD and THC remains challenging. Therefore, this review aims to critically analyze the potential role of CBD as an adjunctive therapy in schizophrenia treatment.

The therapeutic action of CBD may involve activating the 5-hydroxytryptamine 1A receptors and suppressing the G-protein-coupled receptor 55, thereby affecting various neurotransmitter systems. Additionally, the anti-inflammatory and antioxidative effects of CBD may contribute to alleviating neuroinflammation linked to schizophrenia. Compared to typical antipsychotics, CBD demonstrates a lower incidence of side effects and it exhibited favorable tolerability in clinical trials. A 2012 clinical trial demonstrated the efficacy of CBD in reducing both positive and negative symptoms of schizophrenia, presenting a safer profile than that of traditional antipsychotics. However, further research is needed to fully establish the safety and efficacy of CBD as an adjunctive treatment.

Future research directions encompass exploring detailed antipsychotic mechanisms, long-term safety profiles, interactions with current antipsychotics, optimal dosing, and patient-specific factors such as genetic predispositions. Despite these research needs, the potential of CBD to enhance the quality of life and symptom management positions it as a promising candidate for innovative schizophrenia treatment approaches.”

https://pubmed.ncbi.nlm.nih.gov/39068976/

https://www.sciencedirect.com/science/article/abs/pii/S0014299924005107?via%3Dihub

Cannabidiol as an antipsychotic drug

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“Cannabidiol (CBD) is a major phytocannabinoid in the Cannabis sativa plant. In contrast to Δ9-tetrahydrocannabinol (THC), CBD does not produce the typical psychotomimetic effects of the plant. In addition, CBD has attracted increased interest due to its potential therapeutic effects in various psychiatric disorders, including schizophrenia.

Several studies have proposed that CBD has pharmacological properties similar to atypical antipsychotics. Despite accumulating evidence supporting the antipsychotic potential of CBD, the mechanisms of action in which this phytocannabinoid produces antipsychotic effects are still not fully elucidated.

Here, we focused on the antipsychotic properties of CBD indicated by a series of preclinical and clinical studies and the evidence currently available about its possible mechanisms. Findings from preclinical studies suggest that CBD effects may depend on the animal model (pharmacological, neurodevelopmental, or genetic models for schizophrenia), dose, treatment schedule (acute vs. repeated) and route of administration (intraperitoneal vs local injection into specific brain regions).

Clinical studies suggest a potential role for CBD in the treatment of psychotic disorders. However, future studies with more robust sample sizes are needed to confirm these positive findings. Overall, although more studies are needed, current evidence indicates that CBD may be a promising therapeutic option for the treatment of schizophrenia.”

https://pubmed.ncbi.nlm.nih.gov/39029989/

“In conclusion, although much remains to be learned about the mechanisms of action and brain regions involved in CBD effects, several preclinical and clinical studies have indicated that CBD produces antipsychotic effects and is safe and well-tolerated by patients. “

https://www.sciencedirect.com/science/article/abs/pii/S0074774224000655?via%3Dihub

Cannabidiol improves maternal obesity-induced behavioral, neuroinflammatory and neurochemical dysfunctions in the juvenile offspring

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“Maternal obesity is associated with an increased risk of psychiatric disorders such as anxiety, depression, schizophrenia and autism spectrum disorder in the offspring. While numerous studies focus on preventive measures targeting the mothers, only a limited number provide practical approaches for addressing the damages once they are already established.

We have recently demonstrated the interplay between maternal obesity and treatment with cannabidiol (CBD) on hypothalamic inflammation and metabolic disturbances, however, little is known about this relationship on behavioral manifestations and neurochemical imbalances in other brain regions. Therefore, here we tested whether CBD treatment could mitigate anxiety-like and social behavioral alterations, as well as neurochemical disruptions in both male and female offspring of obese dams.

Female Wistar rats were fed a cafeteria diet for 12 weeks prior to mating, and during gestation and lactation. Offspring received CBD (50 mg/kg) from weaning for 3 weeks. Behavioral tests assessed anxiety-like manifestations and social behavior, while neuroinflammatory and neurochemical markers were evaluated in the prefrontal cortex (PFC) and hippocampus.

CBD treatment attenuated maternal obesity-induced anxiety-like and social behavioral alterations, followed by rescuing effects on imbalanced neurotransmitter and endocannabinoid concentrations and altered expression of glial markers, CB1, oxytocin and dopamine receptors, with important differences between sexes.

Overall, the findings of this study provide insight into the signaling pathways for the therapeutic benefits of CBD on neuroinflammation and neurochemical imbalances caused by perinatal maternal obesity in the PFC and the hippocampus, which translates into the behavioral manifestations, highlighting the sexual dimorphism encompassing both the transgenerational effect of obesity and the endocannabinoid system.”

https://pubmed.ncbi.nlm.nih.gov/38608740/

https://www.sciencedirect.com/science/article/abs/pii/S0889159124003556?via%3Dihub

Cannabidiol exhibits anxiolytic-like effects and antipsychotic-like effects in mice models

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“Cannabidiol (CBD), a non-psychoactive compound derived from the cannabis plant, has been confirmed to induce anxiolytic-like and antipsychotic-like effects. However, the exact mechanisms remain unclear.

This study substantiated CBD’s interaction with the 5-HT1A receptor (5-HT1AR) in vitro (CHO cells expressing human 5-HT1AR) and in vivo (rat lower lip retraction test, LLR test). We then assessed the impact of CBD in mice using the stress-induced hyperthermia (SIH) model and the phencyclidine (PCP)-induced negative symptoms of schizophrenia model, respectively. Concurrently, we investigated whether WAY-100635, a typical 5-HT1AR antagonist, could attenuate these effects. Furthermore, the neurotransmitter changes through high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) were studied.

Results revealed that CBD exhibits selective 5-HT1AR agonists-mediated effects in the rat lower lip retraction test, aligning with the robust agonistic (EC50 = 1.75 μM) profile observed in CHO cells. CBD at 3 mg/kg significantly reduced SIH (ΔT), a response that WAY-100635 abolished. Chronic administration of CBD at 100 mg/kg mitigated the increase in PCP-induced immobility time in the forced swim test (FST) and tail suspension test (TST). Moreover, it induced significant alterations in gamma-aminobutyric acid (GABA) and norepinephrine (NE) levels within the hippocampus (HPC). Thus, we concluded that the 5-HT1AR mediates CBD’s anxiolytic-like effects. Additionally, CBD’s effects on the negative symptoms of schizophrenia may be linked to changes in GABA and NE levels in the hippocampus.

These findings offer novel insights for advancing the exploration of CBD’s anxiolytic-like and antipsychotic-like effects.”

https://pubmed.ncbi.nlm.nih.gov/38467272/

https://www.sciencedirect.com/science/article/abs/pii/S0304394024001009?via%3Dihub

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

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“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.”

https://pubmed.ncbi.nlm.nih.gov/38267003/

https://www.thieme-connect.de/products/ejournals/abstract/10.1055/a-2228-6118

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

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“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.”

https://pubmed.ncbi.nlm.nih.gov/38064909/

https://www.sciencedirect.com/science/article/abs/pii/S0165178123005930?via%3Dihub

The psychedelic effects of cannabis: A review of the literature

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“Cannabis and classic psychedelics are controlled substances with emerging evidence of efficacy in the treatment of a variety of psychiatric illnesses. Cannabis has largely not been regarded as having psychedelic effects in contemporary literature, despite many examples of historical use along with classic psychedelics to attain altered states of consciousness.

Research into the “psychedelic” effects of cannabis, and delta-9-tetrahydrocannabinol (THC) in particular, could prove helpful for assessing potential therapeutic indications and elucidating the mechanism of action of both cannabis and classic psychedelics.

This review aggregates and evaluates the literature assessing the capacity of cannabis to yield the perceptual changes, aversiveness, and mystical experiences more typically associated with classic psychedelics such as psilocybin. This review also provides a brief contrast of neuroimaging findings associated with the acute effects of cannabis and psychedelics.

The available evidence suggests that high-THC cannabis may be able to elicit psychedelic effects, but that these effects may not have been observed in recent controlled research studies due to the doses, set, and settings commonly used. Research is needed to investigate the effects of high doses of THC in the context utilized in therapeutic studies of psychedelics aimed to occasion psychedelic and/or therapeutic experiences.

If cannabis can reliably generate psychedelic experiences under these conditions, high-THC dose cannabis treatments should be explored as potential adjunctive treatments for psychiatric disorders and be considered as an active comparator in clinical trials involving traditional psychedelic medications.”

https://pubmed.ncbi.nlm.nih.gov/37947321/

https://journals.sagepub.com/doi/10.1177/02698811231209194

“Psychedelic drugs in the treatment of psychiatric disorders”

https://pubmed.ncbi.nlm.nih.gov/37615227/