I accept the evidence linking cannabis smoking with respiratory illness, but, what alot of these reports do not take into account is that the majority of cannabis smokers put both cannabis and tobacco into their 'joints'. So if a cannabis smoker is also a cigarette smoker then they are obviously going to be at a higher risk of respiratory illness.
As for the mental illness issues, I have spoken in depth with many psychologists and pharmapsychologists (will studying psychology in college) about the realation bewteen cannabis use and mental issues. Many agree that it is
self medication which accounts for large portions of the patients which these studies take into account. Also there is new research which says it contains "concrete" evidence that schizophrenia is caused by a biological predisposition. (see link)
http://query.nytimes.com/gst/fullpage.h ... A96E948260
I do not argue with any of the studies which you cite, but, there is the exact same, if not more, of an illness risk from alcohol and cigarettes. Lung cancer, liver cancer, throat cancer, liver and kidney failure to name only the most obvious.
The most shocking thing is that I can walk down to the local shops buy myself cigarettes & alcohol and get the ball rolling on the above illnesses.
I am not saying that there are no downsides to cannabis smoking but nobody can deny that there are just as many, even more, against drink.
It is easy to quote the studies putting down cannabis, but there is also evidence to suggest that cannabis can be extremely effective as a medicine for various conditions/symptoms, e.g: Nausea from chemotherapy, pain from cancers, pain from arthritis, relief from AIDS related symptoms.
http://www.cmaj.ca/cgi/reprint/162/12/1685.pdf
I know that legalising cannabis to the general population will not have a profound effect on the ailments listed above but I would like to see one medicinal benefit from alcohol or tobacco?
The reason people think of cannabis as such a 'bad' drug is because of the stigma attached to anything illegal. If alcohol and tobacco were illegal people would hold the exact same views about them, maybe even stronger views seeing as they are more harmful.
As I have said before, its easy to pull out studies on the harmful effects, but, its just as easy to do it for numerous legal drugs.