In reply to balmybaldwin:
To suggest that prisons should be drug free is at best idealistic, at worst naive. Having worked in a maximum security prison i know better than most the lengths that some prisoners will go to in order to get drugs into the jail. Prisoners have 24 hours a day to think of ways to bring contraband in, while officers generally can only react to situations. In my time in the service i witnessed some outrageous, some sickening, and some ingenious methods and attempts to smuggle substances in. All mail and packages into prisons are scanned and randomly searched by sniffer dogs, visitors are randomly searched and sniffed by dogs, and the same applies to the staff. Of course there are a few bad apples amongst the staff, as there are in all walks of life, but they are few and far between and certainly a tiny minority.
As an aside, the price of drugs in prisons is about 5 or 6 times higher than on the street because of the scarceness. Yes drugs are common in jail, but they are no more common than they are on the street- you just have a captive market. Perhaps the figures on usage speak more for the type of people in jail than they do about the frequency of use? These are the people that use drugs on the outside, all cooped up together with other people that use drugs on the outside!