“Significant limitations with the currently available antidepressant treatment strategies have inspired research on finding new and more efficient drugs to treat depression. Cannabidiol (CBD) is a non-psychotomimetic component of Cannabis sativa, and emerges in this regard as a promising compound. In 2010, we were the first laboratory to demonstrate that CBD is effective in animal models of predictive of antidepressant effect, a finding now confirmed by several other groups. Recent evidence suggests that CBD promotes both a rapid and a sustained antidepressant effect in animal models. CBD has a complex pharmacology, with the ability to interact with multiple neurotransmitter systems involved in depression, including the serotonergic, glutamatergic, and endocannabinoid systems. Moreover, CBD induces cellular and molecular changes in brain regions related to depression neurobiology, such as increased Brain Derived Neurotrophic Factor (BDNF) levels and synaptogenesis in the medial prefrontal cortex, as well as it increases neurogenesis in the hippocampus. This review presents a comprehensive critical overview of the current literature related to the antidepressant effects of CBD, with focus at the possible mechanisms. Finally, challenges and perspectives for future research are discussed.”
https://www.ncbi.nlm.nih.gov/pubmed/31039391
https://www.sciencedirect.com/science/article/pii/S0891061818302114?via%3Dihub
“Neuropathic pain (NP) is associated with chronic hyperglycemia and emotional disorders such as depression in diabetic patients, complicating the course of treatment. Drugs currently used to treat NP have undesirable side effects, so research on other natural sources has been required.
“Altered endocannabinoid (eCB) signaling is suggested as an important contributor to the pathophysiology of depression.
“Major depressive disorder is a devastating psychiatric disease that afflicts up to 17% of the world’s population. Postmortem brain analyses and imaging studies of patients with depression have implicated basal lateral amygdala (BLA) dysfunction in the pathophysiology of depression. However, the circuit and molecular mechanisms through which BLA neurons modulate depressive behavior are largely uncharacterized. Here, in mice, we identified that BLA cholecystokinin (CCK) glutamatergic neurons mediated negative reinforcement via D2 medium spiny neurons (MSNs) in the nucleus accumbens (NAc) and that chronic social defeat selectively potentiated excitatory transmission of the CCKBLA-D2NAc circuit in susceptible mice via reduction of presynaptic cannabinoid type-1 receptor (CB1R). Knockdown of CB1R in the CCKBLA-D2NAc circuit elevated synaptic activity and promoted stress susceptibility. Notably, selective inhibition of the CCKBLA-D2NAc circuit or administration of synthetic cannabinoids in the NAc was sufficient to produce antidepressant-like effects. Overall, our studies reveal the circuit and molecular mechanisms of depression.”
“The present review will provide an overview of the neurobiology, epidemiology, clinical impact, and treatment of cannabis use disorder (CUD) in mood disorders.
“Previous studies have shown that a cytosine (C) to thymine (T) single nucleotide polymorphism (SNP) of the human cannabinoid receptor 1 (CNR1) gene is associated with positive emotional processing.
C allele carriers are more sensitive to positive emotional stimuli including happiness. The effects of several gene polymorphisms related to sensitivity to emotional stimuli, such as that in the serotonin transporter gene-linked polymorphic region (5HTTLPR), on emotional processing have been reported to differ among cultures-e.g., between those that are independent and interdependent. Thus, we postulated that the effects of the CNR1 genotype on happiness might differ among different cultures because the concept of happiness varies by culture.
We recruited healthy male and female young adults in Japan, where favorable external circumstances determine the concept of happiness, and Canada, where the concept of happiness centers on positive inner feelings, and compared the effects of the CNR1 genotype on both subjective happiness levels (self-evaluation as being a happy person) and situation-specific happiness (happy feelings accompanying various positive events) by using a questionnaire.
We found that the effect of CNR1 on subjective happiness was different between the Japanese and Canadian groups. The subjective happiness level was the highest in Japanese individuals with the CC genotype, whereas in Canadian participants, it was the highest in individuals with the TT genotype. Furthermore, the effects of CNR1 genotype on situation-specific happiness were also different between the groups. Happiness accompanied with being surrounded by happy people was the highest among Japanese individuals with the CC genotype, whereas among Canadian individuals, it was the highest in TT genotype carriers.
These findings suggest that culture and CNR1 polymorphism interact to influence the perception of happiness.”