Impaired mnemonic pattern separation associated with PTSD symptoms paradoxically improves with regular cannabis use

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“Posttraumatic stress disorder (PTSD) is associated with poor hippocampal function and disrupted pattern recognition. Cannabis use is highly prevalent in individuals with PTSD, yet the impact on these cognitive functions is poorly understood. Participants (n = 111) with a range of PTSD symptoms with and without regular cannabis use completed the mnemonic similarity task. We hypothesized that regular use would be associated with alterations in pattern separation ability in individuals with PTSD symptoms. High PTSD symptoms were associated with reduced pattern separation performance in minimal users. Regular users with high PTSD symptoms showed greater pattern separation, but reduced pattern separation with low PTSD symptoms. These results suggest that regular cannabis use may disrupt pattern separation and similar hippocampal-dependent processes, while it may improve pattern separation in individuals with high PTSD symptoms. These cross-sectional results require longitudinal follow-up studies to evaluate the causal effects of regular cannabis use on cognitive function in PTSD.”

https://pubmed.ncbi.nlm.nih.gov/40274935/

“The finding that regular cannabis use was associated with improved pattern separation ability in those reporting more severe PTSD symptoms was unexpected. One possible explanation for this observation is that the endocannabinoid system is altered by trauma exposure and in PTSD.”

https://www.nature.com/articles/s44184-025-00126-w

UK medical cannabis registry: an updated clinical outcomes analysis of patients with post-traumatic stress disorder

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“Background: Cannabis-based medicinal products (CBMPs) are a potential treatment for post-traumatic stress disorder (PTSD), but their long-term efficacy and safety need further investigation. This study assessed the changes in health-related quality of life (HRQoL) and adverse events in PTSD patients prescribed CBMPs.

Research design and methods: This observational cohort study included PTSD patients enrolled on the UK Medical Cannabis Registry for 18 months or longer. Changes in PTSD-specific symptoms (IES-R), anxiety (GAD-7), sleep quality (SQS), and general HRQoL (EQ-5D-5 L) were assessed at 1, 3, 6, 12, and 18 months.

Results: In 269 patients, significant improvements in PTSD symptoms, anxiety, sleep quality, and HRQoL were observed at all follow-up points (p < 0.001). On multivariate logistic regression, male gender (OR = 0.51; 95% CI:0.28-0.94; p = 0.034) was associated with a reduced chance of reporting improvements in IES-R. Adverse events were reported by 70 (26.02%) patients, with insomnia (n = 42, 15.61%) and fatigue (n = 40, 14.87%) being the most common.

Conclusions: CBMPs were associated with improvements in PTSD symptoms, anxiety, sleep, and HRQoL at up to 18 months. Although the study’s observational nature limits causal conclusions, these findings support further assessment of medical cannabis.”

https://pubmed.ncbi.nlm.nih.gov/40235073/

“Cannabis-based medicinal products (CBMPs) have emerged as novel treatments for PTSD. This analysis suggests that initiation of CBMP therapy for up to 18 months is associated with improvements in PTSD-specific, HRQoL, anxiety, and sleep symptoms in PTSD patients. Moreover, CBMPs are largely well tolerated across this short-term follow-up.”

https://www.tandfonline.com/doi/full/10.1080/14737175.2025.2490539#abstract

Cannabidiol Modulates Neuroinflammatory Markers in a PTSD Model Conducted on Female Rats

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“Post-traumatic stress disorder (PTSD) is a debilitating neuropsychiatric condition closely linked to neuroinflammation, with a higher prevalence in women.

Cannabidiol (CBD), a non-psychoactive cannabinoid, has shown promise as a potential treatment for PTSD. In this study, we used a PTSD model in which female rats were subjected to a severe foot shock followed by contextual situational reminders (SRs).

Testing was conducted one month after exposure. The rats received daily CBD injections for three weeks during the SRs, from days 7 to 28. Two days after the final SR, the rats underwent five extinction trials, followed by the forced swim test (FST). After a five-day rest period, the rats were sacrificed, and brain tissues from the medial prefrontal cortex (mPFC) and ventral subiculum (vSUB) were analyzed for inflammatory markers.

Chronic CBD treatment reversed impairments in fear extinction caused by shock and SR. It also reduced learned helplessness in the FST and decreased the upregulation of mPFC-il1β induced by shock and SRs. Additionally, exposure to shock and SRs downregulated mPFC-il6 while upregulating vSUB-il6. CBD treatment further downregulated il6 expression in the vSUB compared to the vehicle groups.

Our findings show that CBD effectively inhibited the development of PTSD-like behaviors and suppressed neuroinflammation in the mPFC.”

https://pubmed.ncbi.nlm.nih.gov/39595561/

https://www.mdpi.com/2218-273X/14/11/1384

Controlled Inhalation of Tetrahydrocannabinol-Predominant Cannabis Flos Mitigates Severity of Post-Traumatic Stress Disorder Symptoms and Improves Quality of Sleep and General Mood in Cannabis-Experienced UK Civilians: A Real-World, Observational Study

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“Introduction: Approximately 4% of the UK population experiences PTSD. Individuals must exhibit symptoms across four clusters to receive a diagnosis: intrusion, avoidance, altered reactivity, and altered mood. Evidence suggests that cannabinoid agonists such as nabilone and tetrahydrocannabinol (THC) may alleviate PTSD symptoms. We investigated the safety and effectiveness of THC-predominant cannabis flowers for inhalation to manage PTSD symptoms in a real-world setting.

Methods: We analysed data from the UK patient registry, T21. Validated questionnaires were used to collect PROMs for health-related quality of life (HRQoL), mood/anxiety, sleep, and PTSD-specific symptoms. Inclusion criteria were (i) a confirmed diagnosis of PTSD, (ii) completed PROMs questionnaires at baseline and at the 3-month follow-up, and (iii) received a prescription for a chemotype 1 (THC-predominant) cannabis flower.

Results: Fifty-eight patients were included, 34 of which also had PROMs recorded at 6 months. Most were males (65.5%) with an average age of 39.2 years who had previously used cannabis illicitly (95.6%). At 3 months, participants reported significant improvements in overall health, mood, and sleep quality (p < 0.001) but not in the proxy for HRQoL (p = 0.052). Similarly, participants reported substantial benefits in managing intrusion symptoms (p < 0.001), mood alterations (p < 0.001), and reactivity alterations (p = 0.002), which were sustained or further improved at 6 months. Participants did not report any side effects associated with CBMPs.

Conclusions: Inhalation of THC is well tolerated and useful for managing symptoms of PTSD in cannabis-experienced individuals. However, further research is needed to evaluate the long-term safety and outcomes of controlled inhalation of CBMP in patients naïve to cannabis.”

https://pubmed.ncbi.nlm.nih.gov/39474239/

“Results from this observational study suggest an association between treatment with THC-predominant cannabis flowers and symptomatic improvement for up to 6 months in a cohort of UK civilians diagnosed with PTSD. The treatment was safe and well tolerated and characterized by marked effects on quality of sleep, general mood, and severity of PTSD-associated symptoms. Despite previous exposure to cannabis, participants continued to report benefits after initiating treatment with THC-predominant cannabis flowers.”

https://karger.com/mca/article/7/1/149/912500/Controlled-Inhalation-of-Tetrahydrocannabinol

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

The Use of Compounds Derived from Cannabis sativa in the Treatment of Epilepsy, Painful Conditions, and Neuropsychiatric and Neurodegenerative Disorders

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“Neurological disorders present a wide range of symptoms and challenges in diagnosis and treatment. Cannabis sativa, with its diverse chemical composition, offers potential therapeutic benefits due to its anticonvulsive, analgesic, anti-inflammatory, and neuroprotective properties.

Beyond cannabinoids, cannabis contains terpenes and polyphenols, which synergistically enhance its pharmacological effects. Various administration routes, including vaporization, oral ingestion, sublingual, and rectal, provide flexibility in treatment delivery.

This review shows the therapeutic efficacy of cannabis in managing neurological disorders such as epilepsy, neurodegenerative diseases, neurodevelopmental disorders, psychiatric disorders, and painful pathologies.

Drawing from surveys, patient studies, and clinical trials, it highlights the potential of cannabis in alleviating symptoms, slowing disease progression, and improving overall quality of life for patients. Understanding the diverse therapeutic mechanisms of cannabis can open up possibilities for using this plant for individual patient needs.”

https://pubmed.ncbi.nlm.nih.gov/38891938/

https://www.mdpi.com/1422-0067/25/11/5749


Cannabidiol ameliorates PTSD-like symptoms by inhibiting neuroinflammation through its action on CB2 receptors in the brain of male mice

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“Post-traumatic stress disorder (PTSD) is a debilitating mental health disease related to traumatic experience, and its treatment outcomes are unsatisfactory.

Accumulating research has indicated that cannabidiol (CBD) exhibits anti-PTSD effects, however, the underlying mechanism of CBD remains inadequately investigated. Although many studies pertaining to PTSD have primarily focused on aberrations in neuronal functioning, the present study aimed to elucidate the involvement and functionality of microglia/macrophages in PTSD while also investigated the modulatory effects of CBD on neuroinflammation associated with this condition.

We constructed a modified single-prolonged stress (SPS) mice PTSD model and verified the PTSD-related behaviors by various behavioral tests (contextual freezing test, elevated plus maze test, tail suspension test and novel object recognition test). We observed a significant upregulation of Iba-1 and alteration of microglial/macrophage morphology within the prefrontal cortex and hippocampus, but not the amygdala, two weeks after the PTSD-related stress, suggesting a persistent neuroinflammatory phenotype in the PTSD-modeled group.

CBD (10 mg/kg, i.p.) inhibited all PTSD-related behaviors and reversed the alterations in both microglial/macrophage quantity and morphology when administered prior to behavioral assessments. We further found increased pro-inflammatory factors, decreased PSD95 expression, and impaired synaptic density in the hippocampus of the modeled group, all of which were also restored by CBD treatment. CBD dramatically increased the level of anandamide, one of the endocannabinoids, and cannabinoid type 2 receptors (CB2Rs) transcripts in the hippocampus compared with PTSD-modeled group.

Importantly, we discovered the expression of CB2Rs mRNA in Arg-1-positive cells in vivo and found that the behavioral effects of CBD were diminished by CB2Rs antagonist AM630 (1 mg/kg, i.p.) and both the behavioral and molecular effects of CBD were abolished in CB2Rs knockout mice. These findings suggest that CBD would alleviate PTSD-like behaviors in mice by suppressing PTSD-related neuroinflammation and upregulation and activation of CB2Rs may serve as one of the underlying mechanisms for this therapeutic effect.

The present study offers innovative experimental evidence supporting the utilization of CBD in PTSD treatment from the perspective of its regulation of neuroinflammation, and paves the way for leveraging the endocannabinoid system to regulate neuroinflammation as a potential therapeutic approach for psychiatric disorders.”

https://pubmed.ncbi.nlm.nih.gov/38759736/

“Cannabidiol alleviated all PTSD-like behaviors in mice by suppressing PTSD-related neuroinflammation.”

https://www.sciencedirect.com/science/article/abs/pii/S0889159124004045?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

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

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