Look, as a local musician who has seen countless people on countless drugs, Weiland was very high last summer when I saw STP in San Diego in July '08. I couldn't say what drugs they were, but that wasn't a sober guy I saw.
Go back and look at the footage from the '08 tour. The Weiland in the April Houdini promo concert seemed lucid, together, able to form sentences.......he was pretty much with it.
In the 2-3 weeks before the '08 tour began, he must have gotten ahold of something. Because the guy I saw, and the guy that appeared on countless youtube videos throughout the summer was totally blitzed!!. Probably presrciption drugs or I wouldn't be surprised if it was combined with cocaine use. Just because he isn't shooting heroin doesn't mean he's not getting off some other way.
Also, on the solo tour he was totally ripped on prescription drugs, especially in the interviews. Probably opiates. The half-closed glassy eyes, the inability to form sentences. Those are tell-tale signs of prescription drug abuse.
I will say this, though. The small spring '09 tour, he looks/acts totally different than last year. He looks almost as if he's been unplugged from the electricty he had last summer. Clean and off cocaine/uppers or is he now just on the heavy opiates? Who's to know?