People with chronic pain who took just a puff of marijuana three times a day got some mild pain relief and, with rare exceptions, did so without getting high, a Canadian study reports. (Yes, they inhaled.) The patients, who suffered from persistent nerve damage that did not respond to other pain drugs, also reported better sleep and less anxiety, the researchers said. The study is one of the first randomly controlled clinical trials to test the pain-relieving properties of smoked marijuana and of its active ingredient, tetrahydrocannabinol, or THC, said Dr. Mark A. Ware, a pain researcher at McGill University...