“Endocannabinoids (eCBS) are involved in the stress response and alterations in eCB signaling may contribute to the etiology of mood disorders.
Exposure to chronic mild stress (CMS), a model of depression, produces downregulation of the CB1 receptor (CB1) in the hippocampus of male rats.
These results effectively demonstrate that CMS significantly alters hippocampal eCB-mediated neurotransmission and synaptic plasticity.”
“The nucleus accumbens (NAc) is a critical component of the reward circuitry, and dysfunction of the NAc may account for anhedonia and other symptoms of depression.
The endocannabinoid (eCB) system regulates mood, emotion, motivation, appetite, body weight, and cognition.
Here, we investigated whether alterations in endocannabinoid (eCB) signaling in the NAc contribute to depression-like behaviors induced by chronic unpredictable stress (CUS) in mice.
These results suggest that downregulation of eCB signaling in the NAc occurs after CUS and contributes to the pathophysiology of depression.”
“Chronic cannabis use is associated with neuroanatomical alterations in the hippocampus. While adverse impacts of cannabis use are generally attributed to Δ9-tetrahydrocannabinol, emerging naturalistic evidence suggests cannabidiol (CBD) is neuroprotective and may ameliorate brain harms associated with cannabis use, including protection from hippocampal volume loss. This study examined whether prolonged administration of CBD to regular cannabis users within the community could reverse or reduce the characteristic hippocampal harms associated with chronic cannabis use.
Results: No change was observed in left or right hippocampus as a whole. However, left subicular complex (parasubiculum, presubiculum, and subiculum) volume significantly increased from baseline to post-treatment (p=0.017 uncorrected) by 1.58% (Cohen’s d=0.63; 2.83% in parasubiculum). Heavy cannabis users demonstrated marked growth in the left subicular complex, predominantly within the presubiculum, and right cornu ammonis (CA)1 compared to lighter users. Associations between greater right subicular complex and total hippocampal volume and higher plasma CBD concentration were evident, particularly in heavy users.
Conclusions: Our findings suggest a restorative effect of CBD on the subicular and CA1 subfields in current cannabis users, especially those with greater lifetime exposure to cannabis. While replication is required in a larger, placebo-controlled trial, these findings support a protective role of CBD against brain structural harms conferred by chronic cannabis use. Furthermore, these outcomes suggest that CBD may be a useful adjunct in treatments for cannabis dependence and may be therapeutic for a range of clinical disorders characterized by hippocampal pathology (e.g., schizophrenia, Alzheimer’s disease, and major depressive disorder).”
“In conclusion, our findings are the first to demonstrate an ameliorating effect of CBD treatment upon brain structural harms characteristic of regular cannabis use. Furthermore, these results speak to the potential for CBD treatment to restore hippocampal pathology in a range of clinical populations (e.g., schizophrenia, Alzheimer’s disease, and major depressive disorder).”
“Cannabis is commonly used to alleviate symptoms of negative affect. However, a paucity of research has examined the acute effects of cannabis on negative affect in everyday life.
The current study provides a naturalistic account of perceived changes in symptoms of depression, anxiety, and stress as a function of dose and concentration of Δ9tetrahydrocannabinol (THC) and cannabidiol (CBD).
Cannabis is commonly used to alleviate depression, anxiety, and stress. Indeed, one of the most commonly reported motives for cannabis use is to cope with stress, with 72% of daily cannabis users reporting use of cannabis to relax or relieve tension.
Results from the present study indicate that medical cannabis users report a substantial and significant reduction in symptoms of negative affect shortly after using cannabis.”
https://www.ncbi.nlm.nih.gov/pubmed/29656267
https://www.sciencedirect.com/science/article/pii/S0165032718303100
“We examined the effects of essential oil from legal (THC <0.2% w/v) hemp variety on the nervous system in 5 healthy volunteers. GC/EIMS and GC/FID analysis of the EO showed that the main components were myrcene and β-caryophyllene.
The experiment consisted of measuring autonomic nervous system (ANS) parameters; evaluations of the mood state; and electroencephalography (EEG) recording before treatment, during treatment, and after hemp inhalation periods as compared with control conditions. The results revealed decreased diastolic blood pressure, increased heart rate, and significant increased skin temperature.
The subjects described themselves as more energetic, relaxed, and calm.
The analysis EEG showed a significant increase in the mean frequency of alpha (8-13 Hz) and significant decreased mean frequency and relative power of beta 2 (18,5-30 Hz) waves. Moreover, an increased power, relative power, and amplitude of theta (4-8 Hz) and alpha brain waves activities and an increment in the delta wave (0,5-4 Hz) power and relative power was recorded in the posterior region of the brain.
These results suggest that the brain wave activity and ANS are affected by the inhalation of the EO of Cannabis sativa suggesting a neuromodular activity in cases of stress, depression, and anxiety.”
“Endocannabinoids are involved in depressive and anxious symptoms and might play a role in stress-associated psychiatric disorders.
While alterations in the endogenous cannabinoid system have been repeatedly found in patients with posttraumatic stress disorder (PTSD), this system has been mostly neglected in borderline personality disorder (BPD). However, there is first evidence for elevated serum levels of the endocannabinoids arachidonylethanolamide (AEA) and 2-arachidonyl-sn-glycerol (2-AG) in BPD patients compared to healthy controls and PTSD patients.
In this study, hair endocannabinoids were analyzed, reflecting long-term endocannabinoid concentrations. We assessed AEA concentrations as well as 2-AG and the 2-AG main isomer 1-AG (1-AG/2-AG) in hair in women with BPD (n = 15) and age- and education-matched healthy women (n = 16).
We found significantly reduced log AEA in BPD patients compared to healthy women (p = .03) but no differences in log 1-AG/2-AG concentrations. In addition, there was no association between 1-AG/2-AG and hair cortisol, but we found a non-significant correlation between hair concentrations of AEA and cortisol (p = .06).
Our data indicate altered long-term release of endogenous cannabinoids in women with BPD depending on type of endocannabinoid. AEA has been suggested to modulate the basal activity of the endocannabinoid system and seems to attenuate depressive and anxious symptoms. Thus, chronically reduced AEA might contribute to psychiatric symptoms in BPD.”
https://www.ncbi.nlm.nih.gov/pubmed/29546791
https://www.tandfonline.com/doi/abs/10.1080/10253890.2018.1451837?journalCode=ists20
“Posttraumatic stress disorder (PTSD) is a debilitating condition highly comorbid with depression. The endocannabinoid (eCB) system and brain-derived neurotrophic factor (BDNF) are suggestively involved in both disorders.
We examined whether cannabinoids can prevent the long-term depressive-like symptoms induced by exposure to the shock and situational reminders (SRs) model of PTSD. The CB1/2 receptor agonist WIN55,212-2 (0.5 mg/kg; i.p.), the fatty acid hydrolase (FAAH) inhibitor URB597 (0.3 mg/kg, i.p.) or vehicle were administered 2 h after severe shock.
Cannabinoids prevented the shock/SRs-induced alterations in social recognition memory, locomotion, passive coping, anxiety-like behavior, anhedonia, fear retrieval, fear extinction and startle response as well as the decrease in BDNF levels in the hippocampus and prefrontal cortex (PFC). Furthermore, significant correlations were found between depressive-like behaviors and BDNF levels in the brain.
The findings suggest that cannabinoids may prevent both depressive- and PTSD-like symptoms following exposure to severe stress and that alterations in BDNF levels in the brains’ fear circuit are involved in these effects.”
https://www.ncbi.nlm.nih.gov/pubmed/29458190
https://www.sciencedirect.com/science/article/pii/S027858461731000X
“In the past decade, remarkable advances have been made in cannabinoid (CB) research. The brain endocannabinoid (eCB) system modulates several neurobiological processes and its dysfunction is suggested to be involved in the pathophysiology of mood and drug use disorders.
The CB1 receptor–mediated signaling, in particular, has been shown to play a critical role in the neural circuitry that mediates mood, motivation, and emotional behaviors. This chapter presents the data pertaining to the involvement of the eCB system in depression, suicide, and alcohol addiction.
It appears that the eCB system might have a critical role in the regulation of mood and emotional responses that are impaired in patients with depression and suicidal behavior.
The data provided in this chapter support the notion that the eCB system might be an additional target for the development of a drug against alcohol use, depression, and suicidal behavior.
Among therapeutic agents, antidepressants are the most widely used drugs for the treatment of depression-related disorders.”
https://www.ncbi.nlm.nih.gov/pubmed/23035286
https://www.ncbi.nlm.nih.gov/books/NBK107200/
“Antidepressant-like effect of Δ9-tetrahydrocannabinol and other cannabinoids isolated from cannabis sativa L. The antidepressant action of cannabis as well as the interaction between antidepressants and the endocannabinoid system has been reported. Results of this study show that Δ9-THC and other cannabinoids exert anti-depressant-like actions, and thus may contribute to the overall mood-elevating properties of cannabis.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2866040/
“Two types of cannabinoid (CB) receptors have been described in the human body: CB1 and CB2 receptors. CB1 receptor distribution may be related to the cannabinoid functions of memory and cognition regulation as well as motor control.
In addition, the endocannabinoid system (ECS) related to CB1 receptors may be involved in human emotion regulation, especially depression occurrence. Indeed, CB1 receptors are all distributed in depression associated neuroanatomical structures and neural circuits.
Both animal experiments and clinical studies have demonstrated that impairment of the ECS pathway is present in depression models and patients, and application of both CB1 receptor agonists and anandamide (cannabinoid-like substance) degradation inhibitors produce similar biochemical and behavioral effects as antidepressants.
These findings provide a solid basis for understanding the ECS role in the formation and development of depression. Therefore, it can be inferred that the ECS may have an important function in both depression treatment and the effects of antidepressants.”
“Hippocampal neurogenesis is suppressed following chronic administration of the major drugs of abuse (including opiates, alcohol, nicotine, and cocaine). However, CB1-knockout mice display significantly decreased hippocampal neurogenesis, suggesting that CB1 receptors activated by endogenous, plant-derived, or synthetic cannabinoids may promote hippocampal neurogenesis.
Cannabinoids can regulate the proliferation of hippocampal NS/PCs by acting on CB1 receptors. They found that both the synthetic cannabinoid HU210 and the endocannabinoid anandamide profoundly promote embryonic hippocampal NS/PC proliferation. Chronic, but not acute, HU210 significantly increases the number of newborn hippocampal neurons in adult rats by promoting NS/PC proliferation.
A significant increase was observed in the hipoppocampal newborn neurons of mice following twice-daily HU210 injection for 10 days.
This suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic administration.”
“Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects.” https://www.jci.org/articles/view/25509