Sleeper hit: Pot isn’t just for partying. Many say they can’t sleep without it. Years ago, Jerry Millen — a TV sportscaster-turned-owner of the dispensary the Greenhouse of Walled Lake — was working as a producer of MMA events, which required frequent flights between Detroit and Tokyo. The jet lag "really kicked my ass," he says. "I would take Ambien CR like it was Tic Tacs because the doctor gave it to me," he says. "And if the doctor gave it to me, it must be safe, right?" Millen later read studies that found sleeping pills could cause cancer. "I'm like, great. I to...