“Recurrent myelitis is one of the predominant characteristics in patients with neuromyelitis optica (NMO). While paresis, visual loss, sensory deficits, and bladder dysfunction are well known symptoms in NMO patients, pain has been recognized only recently as another key symptom of the disease. Although spinal cord inflammation is a defining aspect of neuromyelitis, there is an almost complete lack of data on altered somatosensory function, including pain. Therefore, eleven consecutive patients with NMO were investigated regarding the presence and clinical characteristics of pain. All patients were examined clinically as well as by Quantitative Sensory Testing (QST) following the protocol of the German Research Network on Neuropathic Pain (DFNS). Additionally, plasma endocannabinoid levels and signs of chronic stress and depression were determined. Almost all patients (10/11) suffered from NMO-associated neuropathic pain for the last three months, and 8 out of 11 patients indicated relevant pain at the time of examination. Symptoms of neuropathic pain were reported in the vast majority of patients with NMO. Psychological testing revealed signs of marked depression. Compared to age and gender-matched healthy controls, QST revealed pronounced mechanical and thermal sensory loss, strongly correlated to ongoing pain suggesting the presence of deafferentation-induced neuropathic pain. Thermal hyperalgesia correlated to MRI-verified signs of spinal cord lesion. Heat hyperalgesia was highly correlated to the time since last relapse of NMO. Patients with NMO exhibited significant mechanical and thermal dysesthesia, namely dynamic mechanical allodynia and paradoxical heat sensation. Moreover, they presented frequently with either abnormal mechanical hypoalgesia or hyperalgesia, which depended significantly on plasma levels of the endogenous cannabinoid 2-arachidonoylglycerole (2-AG). These data emphasize the high prevalence of neuropathic pain and hyperalgesia in patients with NMO. The degree of mechanical hyperalgesia reflecting central sensitization of nociceptive pathways seems to be controlled by the major brain endocannabinoid 2-AG.”
Cannabinoid Receptor CB2 Modulates Axon Guidance.
“Navigation of retinal projections towards their targets is regulated by guidance molecules and growth cone transduction mechanisms. Here, we present in vitro and in vivo evidences that the cannabinoid receptor 2 (CB2R) is expressed along the retino-thalamic pathway and exerts a modulatory action on axon guidance….
Overall, this study demonstrates that the contribution of endocannabinoids to brain development is not solely mediated by CB1R, but also involves CB2R.”
The endocannabinoid system as a possible target to treat both the cognitive and emotional features of post-traumatic stress disorder (PTSD).
“Post-traumatic stress disorder (PTSD) is a psychiatric disorder of significant prevalence and morbidity, whose pathogenesis relies on paradoxical changes of emotional memory processing. An ideal treatment would be a drug able to block the pathological over-consolidation and continuous retrieval of the traumatic event, while enhancing its extinction and reducing the anxiety symptoms. While the latter benefit from antidepressant medications, no drug is available to control the cognitive symptomatology. Endocannabinoids regulate affective states and participate in memory consolidation, retrieval, and extinction. Clinical findings showing a relationship between Cannabis use and PTSD, as well as changes in endocannabinoid activity in PTSD patients, further suggest the existence of a link between endocannabinoids and maladaptive brain changes after trauma exposure. Along these lines, we suggest that endocannabinoid degradation inhibitors may be an ideal therapeutic approach to simultaneously treat the emotional and cognitive features of PTSD, avoiding the unwanted psychotropic effects of compounds directly binding cannabinoid receptors.”
Effects of endocannabinoid and endovanilloid systems on aversive memory extinction.
“In contextual fear conditioning animals have to integrate various elemental stimuli into a coherent representation of the condition and then associate context representation with punishment. Although several studies indicated the modulating role of endocannabinoid system (ECS) on the associative learning, ECS effect on contextual fear conditioning requires further investigations. The present study assessed the effects of the increased endocannabinoid anandamide (AEA) tone on acquisition, retrieval and extinction of the contextual fear conditioning…
The present study indicates that ECS controls the extinction of aversive memories in the contextual fear conditioning.”
Cannabis users have higher premorbid IQ than other patients with first onset psychosis.
“A number of studies have reported that patients with psychosis who use cannabis have better cognitive performance than those who do not.
… we tested the hypothesis that patients who smoked cannabis would have a higher premorbid IQ than patients who did not.
Patients who had ever smoked cannabis had significantly higher current and premorbid IQ compared to patients who had never used cannabis…”
The medical necessity for medicinal cannabis: prospective, observational study evaluating the treatment in cancer patients on supportive or palliative care.
“Cancer patients using cannabis report better influence from the plant extract than from synthetic products… We followed patients with a medicinal cannabis license to evaluate the advantages and side effects of using cannabis by cancer patients…
All cancer or anticancer treatment-related symptoms showed significant improvement.
No significant side effects except for memory lessening in patients with prolonged cannabis use were noted.
Conclusion. The positive effects of cannabis on various cancer-related symptoms are tempered by reliance on self-reporting for many of the variables. Although studies with a control group are missing, the improvement in symptoms should push the use of cannabis in palliative treatment of oncology patients.”
http://www.ncbi.nlm.nih.gov/pubmed/23956774
Full Text: http://www.hindawi.com/journals/ecam/2013/510392/
Pot Is Not a Gateway Drug! – DiscoveryNews
“Pot has been blamed for years as a gateway to doing harder drugs. But new data suggests that not only is this blame misappropriated but there’s actually another more accessible and damaging culprit out there.”
Pot Is Not A Gateway Drug! (Video) – msn
“Pot has been blamed for years as a gateway to doing harder drugs. But new data suggests not only is this blame misappropriated, there’s actually another more accessible and damaging culprit out there…”
D.C. Councilmember: ‘Marijuana Does Not Do Harm, It’s Not A Gateway Drug’ – CBSNews
““It’s time for us to recognize that marijuana does not do harm,” said Grosso. “It’s not a gateway drug like people think it is. It’s not causing massive accidents or causing people to go crazy on the streets. And it’s just leading a lot of kids right to jail…””
MYTH: Marijuana Is a “Gateway” Drug – CBSNews
“Despite anti-drug education campaigns which state marijuana is a gateway for harder drug use, new research from the University of New Hampshire says for most people that’s not true.” “But pot does serves as a “gateway,” says Dr. Karen Van Gund, associate professor of sociology., mainly for young people who are poor, unemployed, and subjected to severe psychological stress. In other words, the path to other drugs is not necessarily the pot, but rather the potholes young people encounter on the road.”