Melvyn Weibin Zhang, Roger C. M. Ho

“ Hence, the CB1 receptor has a consequential mediating effect on memory, cognition, and movement [1] . Both the CB1 and CB2 receptors are coupled to inhibitory G protein complexes, which via activation would cause an inhibition of adenylate cyclase. This in turn results in a decreased concentration of cAMP in the cell. Thus, activation would in turn result in the inhibition of neurotransmission [6] .
Thus, when cannabis is consumed, the main ingredient which is tetrahydrocannabinol would bind to the CB1 receptors and this results in an activation of the G protein complexes. ”

“ However, there are ethnic and genetic variants. It should be noted that individuals who are homozygous for the VAL/VAL alleles in the catechol-O-methyltransferase (COMT) genotype tend to be at enhanced risk. Those individuals who are homozygous for the MET/MET alleles in the COMT genotype tend to be not at enhanced risk. [1] In addition, the usage of cannabis has been linked with an earlier age of onset of psychosis [16] . Previous meta-analysis has reported that the average age of onset of psychosis for cannabis users was 2.70 years younger as compared to normal controls [16] . ”

“ In a recent report issued by the Central Narcotics Bureau, Singapore, [4] it has been reported that there has been a massive 29% increment in the number of individuals who have been arrested for cannabis abuse locally, when the statistics for the years of 2012 and 2013 are compared [4] . ”

“ The legal penalties for illegal trafficking of the drug are even more severe. Individuals will face the death sentence if they import or export cannabis of more than 500 grams, resin of more than 200 grams, or mixture of more than 1000 grams. ”

“ The most common method used to consume cannabis is via smoking the product, but it might also be consumed orally in various food products [5] .
2. Pharmacology of Cannabis Understanding the pharmacology of cannabis is essential as it helps to understand the side effects associated with cannabis and its proposed medical benefits. The main constituent that is responsible for the psychoactive properties is tetrahydrocannabinol [6] . In the central nervous system, there are 2 main subtypes of the cannabinoid receptors. These receptors are commonly known as cannabinoid-1 and cannabinoid-2 [7] . ”

“ These effects usually last for 2 to 4 hours. However, the effects of cannabis on cognition might last much longer, ranging from 5 to 12 hours. Those who consume cannabis orally might not experience such significant symptoms as the bioavailability is significantly reduced. Individuals who have consumed high doses might be acutely confused, and they might have other clinical symptoms such as hypotension and hypothermia as well as psychiatric manifestations such as psychosis. ”

“ This would cause a resultant inhibition of the sodium channel, as well as the N and/Q type voltage gated channels. The inwardly rectifying potassium channels are stimulated instead [1] [6] . These changes lead to the euphoric feelings associated with its consumption [1] [6] . ”