Cannabis is basically a safe drug, it would take 80lb to overdose on it, what has happened over the last 10-15 years is the yanks have developed "Skunk" weed this is a genetically modified strain of Marijuana, i have smoked Cannabis for 33 years, i do not smoke it anymore as i do not smoke at all, i may eat some at some time, but i have no interest in smoking, or eating for that matter anything that is a GM product be it illegal or not, especially if it hasn't even been tested by someone responsible such as, dare i say it, a government.
It is the skunk that has raised all the problems that are blamed on cannabis more than previously, it can, i believe, give people mental illnesses, merely because it is 38 times richer in THC than the cannabis that was around when it was made illegal many years ago. Had the government made it legal along time ago, thus taking it out of the realm of the criminals then this problem would not exist. The only drawback for me personally in legalising it would be that it would be smoked by people that i would never have liked to have associated with whilst smoking it. The people i sat around getting stoned with were in general peaceful and sensitive, there were no football hooligans or muggers.