Category Archives: Anxiety

Cannabidiol effects on fear processing and implications for PTSD: Evidence from rodent and human studies

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“Cannabidiol (CBD) modulates aversive memory and its extinction, with potential implications for treating anxiety- and stress-related disorders. Here, we summarize and discuss scientific evidence showing that CBD administered after the acquisition (consolidation) and retrieval (reconsolidation) of fear memory attenuates it persistently in rats and mice. CBD also reduces fear expression and enhances fear extinction. These effects involve the activation of cannabinoid type-1 (CB1) receptors in the dorsal hippocampus, bed nucleus of stria terminalis, and medial prefrontal cortex, comprising the anterior cingulate, prelimbic, and infralimbic subregions. Serotonin type-1A (5-HT1A) receptors also mediate some CBD effects on fear memory. CBD effects on fear memory acquisition vary, depending on the aversiveness of the conditioning procedure. While rodent findings are relatively consistent and encouraging, human studies investigating CBD’s efficacy in modulating aversive/traumatic memories are still limited. More studies are needed to investigate CBD’s effects on maladaptive, traumatic memories, particularly in post-traumatic stress disorder patients.”

https://pubmed.ncbi.nlm.nih.gov/39029986/

“Rodent studies show that CBD can attenuate fear memories at several stages through its interaction with the endocannabinoid system (CB1 receptors). CBD can also reduce the intensity of fear responses through its interaction with 5-HT1A receptors and enhance the extinction of fear. However, the findings regarding CBD effects on fear memory acquisition are mixed. More research is needed to clarify these discrepancies.”

https://www.sciencedirect.com/science/article/abs/pii/S0074774224000503?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

Evaluation of the efficacy, safety, and pharmacokinetics of nanodispersible cannabidiol oral solution (150 mg/mL) versus placebo in mild to moderate anxiety subjects: A double blind multicenter randomized clinical trial

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“Background: Anxiety disorders, an increasingly prevalent global mental health illness, affected approximately 301 million individuals worldwide in 2019. There is an unmet need for the treatment of anxiety disorders, as current therapies are associated with limited response rates, residual symptoms, and adverse effects.

Objectives: To evaluate the efficacy, safety, and pharmacokinetics of nanodispersible cannabidiol (CBD) oral solution versus placebo for the treatment of mild to moderate anxiety disorders.

Methods: This phase 3 prospective, randomized, double blind, parallel group, placebo-controlled, 15-week cohort study took place at multiple sites across India. Eligible participants were randomly assigned to one of the two treatment arms (CBD or placebo) in a 1:1 ratio.

Results: 178 participants were randomized to receive CBD (n=89) or placebo (n=89). The study met both primary (GAD-7 and HAM-A scores) and secondary outcomes (CGI-I, CGI-S, PHQ-9 and PSQI scores). The GAD-7 score difference between the end of treatment and baseline for the CBD versus the placebo was -7.02 (S.E: 0.25, 95% CI -7.52; -6.52), p<0.0001. Similarly, the HAM-A score difference at the end of treatment compared to baseline for the CBD versus the placebo was -11.9 (S.E: 0.33, 95% CI -12.6; -11.3), p<0.0001.

Conclusions: Nanodispersible CBD was therapeutically safe with no serious adverse events, well tolerated, and effective for the treatment of mild to moderate anxiety disorders, as well as associated depression and sleep quality disturbances. These results pave way for probable prospective use of nanodispersible CBD formulation for various psychiatry disorders alone or in conjunction with other drugs.”

https://pubmed.ncbi.nlm.nih.gov/38797087/

“Nanodispersible CBD oral solution was effective treating mild to moderate anxiety.”

https://www.sciencedirect.com/science/article/pii/S1876201824001667?via%3Dihub

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

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

Cannabinoids in the Treatment of Selected Mental Illnesses: Practical Approach and Overview of the Literature

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“Although an increasing number of patients suffering from mental illnesses self-medicate with cannabis, current knowledge about the efficacy and safety of cannabis-based medicine in psychiatry is still extremely limited. So far, no cannabis-based finished product has been approved for the treatment of a mental illness.

There is increasing evidence that cannabinoids may improve symptoms in autism spectrum disorder (ASD), Tourette syndrome (TS), anxiety disorders, and post-traumatic stress disorder (PTSD). According to surveys, patients often use cannabinoids to improve mood, sleep, and symptoms of attention deficit/hyperactivity disorder (ADHD).

There is evidence suggesting that tetrahydrocannabinol (THC) and THC-containing cannabis extracts, such as nabiximols, can be used as substitutes in patients with cannabis use disorder.

Preliminary evidence also suggests an involvement of the endocannabinoid system (ECS) in the pathophysiology of TS, ADHD, and PTSD. Since the ECS is the most important neuromodulatory system in the brain, it possibly induces beneficial effects of cannabinoids by alterations in other neurotransmitter systems.

Finally, the ECS is an important stress management system. Thus, cannabinoids may improve symptoms in patients with mental illnesses by reducing stress. Practically, cannabis-based treatment in patients with psychiatric disorders does not differ from other indications. The starting dose of THC-containing products should be low (1-2.5 mg THC/day), and the dose should be up-titrated slowly (by 1-2.5 mg every 3-5 days). The average daily dose is 10-20 mg THC. In contrast, cannabidiol (CBD) is mainly used in high doses>400 mg/day.”

https://pubmed.ncbi.nlm.nih.gov/38428836/

https://www.thieme-connect.de/products/ejournals/abstract/10.1055/a-2256-0098

UK Medical Cannabis Registry: a case series analyzing clinical outcomes of medical cannabis therapy for generalized anxiety disorder patients

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“This study aims to analyze changes in health-related quality of life (HRQoL) and safety in patients with generalized anxiety disorder (GAD) prescribed a homogenous selection of cannabis-based medicinal products (CBMPs). Patients prescribed Adven CBMPs (Curaleaf International, UK) for GAD were identified from the UK Medical Cannabis Registry. Primary outcomes were changes in patient-reported outcome measures (PROMs) from baseline up to 12 months, including GAD-7, Single-Item Sleep Quality Scale (SQS), and EQ-5D-5L. Adverse events were recorded using CTCAE version 4.0. A total of 120 patients were identified for inclusion, of which 38 (31.67%), 52 (43.33%), and 30 (25.00%) were prescribed oils, dried flower, and both formulations of CBMP. Associated improvements in GAD-7, SQS, and EQ-5D-5L at 1, 3, 6, and 12 months were observed compared to baseline (P < 0.010). There were 24 (20.00%) patients who reported 442 (368.33%) adverse events, most of which were mild (n = 184, 41.63%) and moderate (n = 197, 44.57%). This study reports an association between initiation of a homogeneous CBMP therapy and improvements in anxiety severity and HRQoL in individuals with GAD. Moreover, therapy was well-tolerated at 12 months follow-up. Further investigation through randomized controlled trials will ultimately be required to determine causation.”

https://pubmed.ncbi.nlm.nih.gov/38299624/

https://journals.lww.com/intclinpsychopharm/fulltext/9900/uk_medical_cannabis_registry__a_case_series.125.aspx

Acute and Extended Anxiolytic Effects of Cannabidiol in Cannabis Flower: A Quasi-Experimental ad libitum Use Study

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“Objective: Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) have varying pharmacological actions with differential effects on acute and extended affective states, incuding anxiety. We aimed to study these effects on anxiety in legal market forms of cannabis. 

Method: This study makes use of a nonequivalent control group quasiexperimental design. Forty-two participants with anxiety symptions who were not using cannabis were compared to 258 participants with anxiety symptoms who used cannabis flower (∼3-4 times per week). Participants who used cannabis were randomly assigned to one of three legal market cannabis conditions; THC-dominant (24% THC, <1% CBD), THC+CBD (12% THC, 12% CBD), or CBD-dominant (<1% THC, 24% CBD). Changes in anxiety symptoms over 4-weeks were measured by the Patient Global Impression of Change (PGIC) scale and the Depression, Anxiety, and Stress Scale (DASS). Acute changes in subjective mood immediately after cannabis use were measured by the Profile of Mood States (POMS) Elation, Tension, and Paranoia subscales and the Addiction Research Center Inventory intoxication scale. 

Results: While all participants reported anxiety reductions over the 4-week study on the PGIC (F=30.65, p<0.001) and DASS anxiety measures (F=115.88, p<0.001), ad libitum CBD-dominant cannabis use was associated with lower scores on the DASS anxiety subscale compared to THC-dominant use when accounting for frequency of use (difference=-1.03, SE=0.45, p=0.02). Similarly, acute CBD-dominant cannabis use was associated with lower scores on the POMS tension and paranoia subscales (POMS tension: CBD-dominant vs. THC-dominant: difference=-0.41 SE=0.1, p<0.001; CBD-dominant vs. THC+CBD: difference=-0.28, SE=0.07, p=0.04; POMS paranoia: CBD-dominant vs. THC-dominant: difference=-0.49, SE=0.1, p<0.001; CBD-dominant vs. THC+CBD: difference=-0.33, SE=0.09, p=0.01). Participants in all cannabis conditions experienced acute changes in positive mood and subjective drug effects. 

Conclusions: This study provides novel information on the impacts of legal market cannabis with varying ratios of THC to CBD in indviduals with anxiety symptoms. Findings suggest that THC did not increase anxiety and that CBD-dominant forms of cannabis were associated with acute tension reduction that may translate to longer-term reductions in anxiety symptoms.”

https://pubmed.ncbi.nlm.nih.gov/38252547/

https://www.liebertpub.com/doi/10.1089/can.2023.0187

The impact of cannabidiol placebo on responses to an acute stressor: A replication and proof of concept study

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“Background: Our group has previously reported that cannabidiol (CBD) expectancy alone blunts markers of stress, particularly during anticipation, but it is not clear the extent to which such findings were specific to the methods utilized.

Aims: To examine CBD-related placebo effects on stress reactivity and anticipation and to validate a protocol to be used in a neuroimaging study.

Methods: Forty-eight healthy adults (24 female) were randomly assigned to be informed that they ingested a CBD-containing oil or a CBD-free oil despite receiving the same oil (CBD-free). Following oil administration, participants engaged in a laboratory stressor and were then incorrectly informed that they would engage in a second more difficult task following a waiting period. Subjective state (sedation, energy, stress, anxiety) and heart rate were assessed at baseline, post-oil administration, immediately following the first stressor, and while anticipating the second stressor.

Results: Subjective stress and anxiety were significantly elevated immediately following the stressor (p-values < 0.001). CBD expectancy was associated with increased subjective sedation (p < 0.01) and tended to be associated with blunted subjective stress (p = 0.053). Post hoc within-condition pairwise compassions suggested a return to pre-stressor levels during the anticipation period in the CBD condition for subjective stress and anxiety (p = 0.784, 0.845), but not the CBD-free condition (p = 0.025, 0.045).

Conclusion: Results replicate and extend previous findings that CBD expectancy alone can impact stress- and anxiety-relevant responses in the laboratory context.”

https://pubmed.ncbi.nlm.nih.gov/38214314/

https://journals.sagepub.com/doi/10.1177/02698811231219060