They referenced it to an article written by Linda Diebel of the Toronto Star. This is the relevant paragraph from the article:
"He tells an anecdote about his conversion to federalism. Going door-to-door for the PQ, he was invited in by a man, a federalist, whose wife kept bringing rum-and-cokes. "I came at 5, I left at 10 and I was completely drunk. I said to him, `Well, maybe you're right.' I don't know how I found my way home. I went to sleep right away. Since then, I've never been an activist for the separatist cause � and I never drank rum-and-coke. A double healing."
As meth was not mentioned in the article it's inclusion in the Wikipedia piece is most likely the work of vandals.