Category Archives: Depression

Cannabinoids elicit antidepressant-like behavior and activate serotonergic neurons through the medial prefrontal cortex

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“Preclinical and clinical studies show that cannabis modulates mood and possesses antidepressant-like properties, mediated by the agonistic activity of cannabinoids on central CB1 receptors (CB1Rs). The action of CB1R agonists on the serotonin (5-HT) system, the major transmitter system involved in mood control and implicated in the mechanism of action of antidepressants, remains however poorly understood.

In this study, we demonstrated that, at low doses, the CB1R agonist WIN55,212-2 [R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl) methanone mesylate] exerts potent antidepressant-like properties in the rat forced-swim test (FST).

This effect is CB1R dependent because it was blocked by the CB1R antagonist rimonabant and is 5-HT mediated because it was abolished by pretreatment with the 5-HT-depleting agent parachlorophenylalanine. Then, using in vivo electrophysiology, we showed that low doses of WIN55,212-2 dose dependently enhanced dorsal raphe nucleus 5-HT neuronal activity through a CB1R-dependent mechanism.

Conversely, high doses of WIN55,212-2 were ineffective in the FST and decreased 5-HT neuronal activity through a CB1R-independent mechanism. The CB1R agonist-induced enhancement of 5-HT neuronal activity was abolished by total or medial prefrontocortical, but not by lateral prefrontocortical, transection. Furthermore, 5-HT neuronal activity was enhanced by the local microinjection of WIN55,212-2 into the ventromedial prefrontal cortex (mPFCv) but not by the local microinjection of WIN55,212-2 into the lateral prefrontal cortex. Similarly, the microinjection of WIN55,212-2 into the mPFCv produced a CB1R-dependent antidepressant-like effect in the FST.

These results demonstrate that CB1R agonists possess antidepressant-like properties and modulate 5-HT neuronal activity via the mPFCv.”

“These results establish that low doses of a CB1R agonist elicit potent antidepressant-like behavior and enhance 5-HT neurotransmission, mediated by CB1R activation in the mPFCv. Conversely, high doses nullify antidepressant-like behavior and markedly attenuate 5-HT neurotransmission, an effect that appears to be instigated by a non-CB1R mechanism.”

https://pubmed.ncbi.nlm.nih.gov/17959812/

In the weeds: A comprehensive review of cannabis; its chemical complexity, biosynthesis, and healing abilities

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“For millennia, various cultures have utilized cannabis for food, textile fiber, ethno-medicines, and pharmacotherapy, owing to its medicinal potential and psychotropic effects. An in-depth exploration of its historical, chemical, and therapeutic dimensions provides context for its contemporary understanding. The criminalization of cannabis in many countries was influenced by the presence of psychoactive cannabinoids; however, scientific advances and growing public awareness have renewed interest in cannabis-related products, especially for medical use.

Described as a ‘treasure trove,’ cannabis produces a diverse array of cannabinoids and non-cannabinoid compounds. Recent research focuses on cannabinoids for treating conditions such as anxiety, depression, chronic pain, Alzheimer’s, Parkinson’s, and epilepsy. Additionally, secondary metabolites like phenolic compounds, terpenes, and terpenoids are increasingly recognized for their therapeutic effects and their synergistic role with cannabinoids. These compounds show potential in treating neuro and non-neuro disorders, and studies suggest their promise as antitumoral agents. This comprehensive review integrates historical, chemical, and therapeutic perspectives on cannabis, highlighting contemporary research and its vast potential in medicine.”

https://pubmed.ncbi.nlm.nih.gov/39056093/

https://www.sciencedirect.com/science/article/pii/S2214750024000684?via%3Dihub

Therapeutic potential of cannabidiol in depression

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“Major depressive disorder (MDD) is a widespread and debilitating condition affecting a significant portion of the global population.

Traditional treatment for MDD has primarily involved drugs that increase brain monoamines by inhibiting their uptake or metabolism, which is the basis for the monoaminergic hypothesis of depression. However, these treatments are only partially effective, with many patients experiencing delayed responses, residual symptoms, or complete non-response, rendering the current view of the hypothesis as reductionist.

Cannabidiol (CBD) has shown promising results in preclinical models and human studies. Its mechanism is not well-understood, but may involve monoamine and endocannabinoid signaling, control of neuroinflammation and enhanced neuroplasticity. This chapter will explore CBD’s effects in preclinical and clinical studies, its molecular mechanisms, and its potential as a treatment for MDD.”

https://pubmed.ncbi.nlm.nih.gov/39029987/

“CBD exhibits a multi-pharmacological profile with a complex and not fully understood mechanism of action. It engages some pathways similar to those targeted by other antidepressant drugs, such as the facilitation of serotonergic and BDNF-TrkB signaling. However, it also activates distinct pathways that differ from traditional antidepressants.”

https://www.sciencedirect.com/science/article/abs/pii/S0074774224000850?via%3Dihub

Acute effects of cannabigerol on anxiety, stress, and mood: a double-blind, placebo-controlled, crossover, field trial

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“Cannabigerol (CBG) is a phytocannabinoid increasing in popularity, with preclinical research indicating it has anxiolytic and antidepressant effects. However, there are no published clinical trials to corroborate these findings in humans.

The primary objective of this study was to examine acute effects of CBG on anxiety, stress, and mood. Secondary objectives were to examine whether CBG produces subjective drug effects or motor and cognitive impairments. A double-blind, placebo-controlled cross-over field trial was conducted with 34 healthy adult participants. Participants completed two sessions (with a one-week washout period) via Zoom. In each, they provided ratings of anxiety, stress, mood, and subjective drug effects prior to double-blind administration of 20 mg hemp-derived CBG or placebo tincture (T0). These ratings were collected again after participants ingested the product and completed an online survey (T1), the Trier Social Stress Test (T2), a verbal memory test and the DRUID impairment app (T3).

Relative to placebo, there was a significant main effect of CBG on overall reductions in anxiety as well as reductions in stress at T1. CBG also enhanced verbal memory relative to placebo. There was no evidence of subjective drug effects or impairment. CBG may represent a novel option to reduce stress and anxiety in healthy adults.”

https://pubmed.ncbi.nlm.nih.gov/39003387/

“In conclusion, results of this double-blind, placebo-controlled, cross-over field trial indicate that 20 mg of hemp-derived CBG reduces subjective ratings of anxiety and stress in healthy cannabis-using adults in the absence of motor or cognitive impairment, intoxication, or other subjective drug effects (e.g., heart palpitations, dry mouth).”

https://www.nature.com/articles/s41598-024-66879-0

In Vitro and In Vivo Anti-Inflammatory and Antidepressant-like Effects of Cannabis sativa L. Extracts

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“Cannabis sativa L. has been widely used by humans for centuries for various purposes, such as industrial, ceremonial, medicinal, and food. The bioactive components of Cannabis sativa L. can be classified into two main groups: cannabinoids and terpenes.

These bioactive components of Cannabis sativa L. leaf and inflorescence extracts were analyzed. Mice were systemically administered 30 mg/kg of Cannabis sativa L. leaf extract 1 h before lipopolysaccharide (LPS) administration, and behavioral tests were performed. We conducted an investigation into the oxygen saturation, oxygen tension, and degranulation of mast cells (MCs) in the deep cervical lymph nodes (DCLNs). To evaluate the anti-inflammatory effect of Cannabis sativa L. extracts in BV2 microglial cells, we assessed nitrite production and the expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α.

The main bioactive components of the Cannabis sativa L. extracts were THCA (a cannabinoid) and β-caryophyllene (a terpene). Cannabis sativa L. leaf extract reduced the immobility time in the forced swimming test and increased sucrose preference in the LPS model, without affecting the total distance and time in the center in the open field test. Additionally, Cannabis sativa L. leaf extract improved oxygen levels and inhibited the degranulation of MCs in DCLNs.

The Cannabis sativa L. extracts inhibited IL-1β, IL-6, TNF-α, nitrite, iNOS, and COX-2 expression in BV2 microglia cells. The efficacy of Cannabis sativa L. extracts was suggested to be due to the entourage effect of various bioactive phytochemicals.

Our findings indicate that these extracts have the potential to be used as effective treatments for a variety of diseases associated with acute inflammatory responses.”

https://pubmed.ncbi.nlm.nih.gov/38931051/

“The results of our study suggest that Cannabis sativa L. leaf and inflorescence extracts have the potential to be an effective treatment for a variety of diseases associated with inflammatory responses. However, we are required to conduct future experiments such as Western blotting and immunofluorescence to investigate the mechanisms of Cannabis sativa L. leaf and inflorescence extracts’ antidepressant-like effects and anti-inflammatory activity.”

https://www.mdpi.com/2223-7747/13/12/1619

Medicinal Cannabis oil improves anxiety-like and depressive-like behaviors in CCS mice via the BDNF/TRPC6 signaling pathway

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“Background: Post-traumatic stress disorder (PTSD) refers to a chronic impairing psychiatric disorder occurring after exposure to the severe traumatic event. Studies have demonstrated that medicinal cannabis oil plays an important role in neuroprotection, but the mechanism by which it exerts anti-PTSD effects remains unclear.

Methods: The chronic complex stress (CCS) simulating the conditions of long voyage stress for 4 weeks was used to establish the PTSD mice model. After that, behavioral tests were used to evaluate PTSD-like behaviors in mice. Mouse brain tissue index was detected and hematoxylin-eosin staining was used to assess pathological changes in the hippocampus. The indicators of cell apoptosis and the BDNF/TRPC6 signaling activation in the mice hippocampus were detected by western blotting or real-time quantitative reverse transcription PCR experiments.

Results: We established the PTSD mice model induced by CCS, which exhibited significant PTSD-like phenotypes, including increased anxiety-like and depression-like behaviors. Medicinal cannabis oil treatment significantly ameliorated PTSD-like behaviors and improved brain histomorphological abnormalities in CCS mice. Mechanistically, medicinal cannabis oil reduced CCS-induced cell apoptosis and enhanced the activation of BDNF/TRPC6 signaling pathway.

Conclusions: We constructed a PTSD model with CCS and medicinal cannabis oil that significantly improved anxiety-like and depressive-like behaviors in CCS mice, which may play an anti-PTSD role by stimulating the BDNF/TRPC6 signaling pathway.”

https://pubmed.ncbi.nlm.nih.gov/38641178/

https://www.sciencedirect.com/science/article/abs/pii/S016643282400161X?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

How depression and antidepressant drugs affect endocannabinoid system?-review of clinical and preclinical studies

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“As major depressive disorder is becoming a more and more common issue in modern society, it is crucial to discover new possible grip points for its diagnosis and antidepressive therapy.

One of them is endocannabinoid system, which has been proposed as a manager of emotional homeostasis, and thus, endocannabinoid alterations have been found in animals undergoing various preclinical models of depression procedures as well as in humans suffering from depressive-like disorders.

In this review article, studies regarding those alterations have been summed up and analyzed. Another important issue raised by the researchers is the impact of currently used antidepressive drugs on endocannabinoid system so that it would be possible to predict reversibility of endocannabinoid alterations following stress exposure and, in the future, to be able to design individually personalized therapies.

Preclinical studies investigating this topic have been analyzed and described in this article. Unfortunately, too few clinical studies in this field exist, what indicates an urgent need for collecting such data, so that it would be possible to compare them with preclinical outcomes and draw reliable conclusions.”

https://pubmed.ncbi.nlm.nih.gov/38280009/

https://link.springer.com/article/10.1007/s00210-023-02938-z

Effectiveness of Medical Cannabis for the Treatment of Depression: A Naturalistic Outpatient Study

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“Background: There is a lack of studies on the course and effectiveness of medical cannabis in the treatment of major depressive disorder (MDD).

Methods: Retrospective longitudinal (18 weeks) study of n=59 outpatients with MDD, treated with medical cannabis via a telemedical platform. Previous treatment with antidepressant medication was required for inclusion into the study. Standardized data collection was carried out at entry and during monthly consultations. Severity of depression was measured on a 0-10 point rating scale. Side-effects were assessed by a checklist.

Results: Patients were 20-54 years old; 72.9% were male; one third reported times of regular cannabis consumption within the previous five years. Drop-out rate was 22% after 18 weeks. Mean severity of depression decreased from 6.9 points (SD 1.5) at entry to 3.8 points (2.7) at week 18 (baseline observation carried forward; 95% CI for the mean difference: 2.4 to 3.8; p<0.001). A treatment response (>50% reduction of the initial score) was seen in 50.8% at week 18. One third of patients complained about side effects, none was considered as severe. Concomitant antidepressant medication (31% of patients) was not associated with outcome.

Conclusions: Medical cannabis was well tolerated and dropout rate was comparable to those in clinical trials of antidepressant medication. Patients reported a clinically significant reduction of depression severity. Further research on the effectiveness of medical cannabis for MDD seems warranted. Risks of this medication, such as sustaining or inducing a cannabis use disorder, or side effects such as poor concentration, must be taken into consideration.”

https://pubmed.ncbi.nlm.nih.gov/38211630/

https://www.thieme-connect.de/products/ejournals/abstract/10.1055/a-2215-6114

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/