Category Archives: Post-Traumatic Stress Disorder (PTSD)

Does cannabis use predict aggressive or violent behavior in psychiatric populations? A systematic review

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“Background: Despite an increase in information evaluating the therapeutic and adverse effects of cannabinoids, many potentially important clinical correlates, including violence or aggression, have not been adequately investigated.Objectives: In this systematic review, we examine the published evidence for the relationship between cannabis and aggression or violence in individuals with psychiatric disorders.Methods: Following PRISMA guidelines, articles in English were searched on PubMed, Google Scholar, MEDLINE, and PsycINFO from database inception to January 2022. Data for aggression and violence in people with psychiatric diagnoses were identified during the searches.Results: Of 391 papers identified within the initial search, 15 studies met inclusion criteria. Cross-sectional associations between cannabis use and aggression or violence in samples with post-traumatic stress disorder (PTSD) were found. Moreover, a longitudinal association between cannabis use and violence and aggression was observed in psychotic-spectrum disorders. However, the presence of uncontrolled confounding factors in the majority of included studies precludes any causal conclusions.Conclusion: Although cannabis use is associated with aggression or violence in individuals with PTSD or psychotic-spectrum disorders, causal conclusions cannot be drawn due to methodological limitations observed in the current literature. Well-controlled, longitudinal studies are needed to ascertain whether cannabis plays a causal role on subsequent violence or aggression in mental health disorders.”

https://pubmed.ncbi.nlm.nih.gov/36137273/

https://www.tandfonline.com/doi/abs/10.1080/00952990.2022.2118060?journalCode=iada20

Social stress under binge-like alcohol withdrawal in adolescence: evidence of cannabidiol effect on maladaptive plasticity in rats

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Psychological Medicine

“Background: Alcohol binge drinking may compromise the functioning of the nucleus accumbens (NAc), i.e. the neural hub for processing reward and aversive responses.

Methods: As socially stressful events pose particular challenges at developmental stages, this research applied the resident-intruder paradigm as a model of social stress, to highlight behavioural neuroendocrine and molecular maladaptive plasticity in rats at withdrawal from binge-like alcohol exposure in adolescence. In search of a rescue agent, cannabidiol (CBD) was selected due to its favourable effects on alcohol- and stress-related harms.

Results: Binge-like alcohol exposed intruder rats displayed a compromised defensive behaviour against the resident and a blunted response of the stress system, in addition to indexes of abnormal dopamine (DA)/glutamate plasticity and dysfunctional spine dynamics in the NAc. CBD administration (60 mg/kg) was able to: (1) increase social exploration in the binge-like alcohol exposed intruder rats, at the expenses of freezing time, and in control rats, which received less aggressive attacks from the resident; (2) reduce corticosterone levels independently on alcohol previous exposure; (3) restore DA transmission and (4) facilitate excitatory postsynaptic strength and remodelling.

Conclusions: Overall, the maladaptive behavioural and synaptic plasticity promoted by the intersection between binge-like alcohol withdrawal and exposure to adverse social stress can be rescued by a CBD détente effect that results in a successful defensive strategy, supported by a functional endocrine and synaptic plasticity. The current data highlight CBD’s relevant therapeutic potential in alcohol- and stress-related harms, and prompt further investigation on its molecular targets.”

https://pubmed.ncbi.nlm.nih.gov/36065905/

https://www.cambridge.org/core/journals/psychological-medicine/article/abs/social-stress-under-bingelike-alcohol-withdrawal-in-adolescence-evidence-of-cannabidiol-effect-on-maladaptive-plasticity-in-rats/0A68E4159FDCAF5592BD10DEC4DAC9F8

Cannabidiol impairs fear memory reconsolidation in female rats through dorsal hippocampus CB1 but not CB2 receptor interaction

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European Neuropsychopharmacology

“Women present increased susceptibility to anxiety- and stress-related disorders compared to men. A potentially promising pharmacological-based strategy to regulate abnormal aversive memories disrupts their reconsolidation stage after reactivation and destabilization.

Male rodent findings indicate that cannabidiol (CBD), a relatively safe and effective treatment for several mental health conditions, can impair the reconsolidation of aversive memories. However, whether and how CBD influences it in females is still unknown.

The present study addressed this question in contextually fear-conditioned female rats.

We report that systemically administered CBD impaired their reconsolidation, reducing freezing expression for over a week. This action was restricted to a time when the reconsolidation presumably lasted (< six hours post-retrieval) and depended on memory reactivation/destabilization. Moreover, the impairing effects of CBD on memory reconsolidation relied on the activation of cannabinoid type-1 but not type-2 receptors located in the CA1 subregion of the dorsal hippocampus.

CBD applied directly to this brain area was sufficient to reproduce the effects of systemic CBD treatment. Contextual fear memories attenuated by CBD did not show reinstatement, an extinction-related feature. By demonstrating that destabilized fear memories are sensitive to CBD and how it hinders mechanisms in the DH CA1 that may restabilize them in female rats, the present findings concur that reconsolidation blockers are viable and could be effective in disrupting abnormally persistent and distressing aversive memories such as those related to posttraumatic stress disorder.”

https://pubmed.ncbi.nlm.nih.gov/36049316/

https://www.sciencedirect.com/science/article/abs/pii/S0924977X22008367?via%3Dihub

Cannabidiol Prevents Spontaneous Fear Recovery after Extinction and Ameliorates Stress-Induced Extinction Resistance

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ijms-logo

“Cannabidiol, the main non-psychotropic constituent of cannabis, has potential as a treatment for anxiety-related disorders since it reduces learned fear expression and enhances fear extinction.

The return of fear over time after successful extinction and stress-induced extinction resistance are potential barriers to the treatment of these disorders with extinction-based psychological therapy. In two experiments using rats subjected to auditory fear conditioning, we determined the effects of systemic cannabidiol treatment on (1) delayed extinction and later spontaneous fear recovery, and (2) extinction resistance caused by immediate extinction (the immediate extinction deficit (IED)). In Experiment 1, cannabidiol was given before delayed extinction occurring 24 h after conditioning, with extinction recall and spontaneous fear recovery tested drug-free 1 and 21 days after extinction, respectively.

We found that cannabidiol had no effect on extinction recall but it prevented spontaneous fear recovery. In Experiment 2, the IED procedure was first validated, with immediate extinction occurring 30 min after conditioning. We confirmed that immediate extinction impaired extinction recall, compared to delayed extinction. Next, cannabidiol was given before immediate or no extinction, with extinction recall tested drug-free the next day. We found that cannabidiol rescued the IED, which did not involve effects on fear memory consolidation.

In summary, cannabidiol prevented spontaneous fear recovery after delayed extinction and ameliorated extinction resistance caused by immediate extinction. Although the pharmacological mechanisms underlying these effects remain to be determined, our results add to evidence indicating that cannabidiol might prove useful as an adjunct for potentiating the psychological treatment of anxiety-related disorders.”

https://pubmed.ncbi.nlm.nih.gov/36012600/

https://www.mdpi.com/1422-0067/23/16/9333/htm

Cannabinoid modulation of brain activation during volitional regulation of negative affect in trauma-exposed adults

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Neuropharmacology

“Emotion dysregulation is considered a core component of posttraumatic stress disorder (PTSD). Cognitive reappraisal is one therapeutic emotion regulation strategy that has been widely studied among individuals with mood and anxiety disorders, and numerous differences in brain activation patterns have been shown between individuals with and without PTSD during tasks of cognitive reappraisal.

Prior research among healthy subjects suggests that an acute, low dose of Δ9-tetrahydrocannabinol (THC) could attenuate the neurophysiological discrepancies that exist between individuals with and without PTSD during tasks of emotional processing; however, the effect of an acute, low dose of THC on corticolimbic activity during emotion regulation among individuals with PTSD has not yet been studied.

The present study aimed to investigate the effect of THC on negative affect and brain activation in a priori regions of interest during cognitive reappraisal among trauma-exposed individuals with and without PTSD.

Using a double-blind design, 51 individuals were randomized to receive THC or placebo (PBO) before participating in a well-established emotion regulation task during functional magnetic resonance imaging (fMRI).

THC but not PBO reduced negative affect during reappraisal, and THC increased dorsomedial prefrontal cortex (dmPFC) activation in response to neutral images. Individuals with PTSD displayed less activation in the angular gyrus, overall, compared to the trauma-exposed control (TEC) group, however THC increased angular gyrus activation in the PTSD group so that there was no significant difference in angular gyrus activation between the TEC and PTSD groups that received THC.

Compared to PBO, THC also increased cerebellar activation during exposure to neutral images in individuals with PTSD. Lastly, in participants that received THC, greater posterior cingulate cortex (PCC)/precuneus activation during reappraisal was associated with less self-reported negative affect following reappraisal blocks.

Together these findings suggest that THC may prove to be a beneficial pharmacological adjunct to cognitive reappraisal therapy in the treatment of PTSD.”

https://pubmed.ncbi.nlm.nih.gov/35981598/

“Δ9-tetrahydrocannabinol (THC) reduced negative affect during reappraisal.”

https://www.sciencedirect.com/science/article/abs/pii/S0028390822002817?via%3Dihub

Constituents of Cannabis Sativa

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“The Cannabis sativa plant has been used medicinally and recreationally for thousands of years, but recently only relatively some of its constituents have been identified.

There are more than 550 chemical compounds in cannabis, with more than 100 phytocannabinoids being identified, including Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD).

These phytocannabinoids work by binding to the cannabinoid receptors, as well as other receptor systems. Also within cannabis are the aromatic terpenes, more than 100 of which have been identified.

Cannabis and its constituents have been indicated as therapeutic compounds in numerous medical conditions, such as pain, anxiety, epilepsy, nausea and vomiting, and post-traumatic stress disorder.

This chapter provides an overview of some of the biological effects of a number of the cannabinoids and terpenes, as well as discussing their known mechanisms of action and evidence of potential therapeutic effects.”

https://pubmed.ncbi.nlm.nih.gov/33332000/

https://link.springer.com/chapter/10.1007%2F978-3-030-57369-0_1

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

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

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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

Meet Your Stress Management Professionals: The Endocannabinoids

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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

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

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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