I think the joke was that Turner is nuts not a druggie. But the irony is still there, for obvious reasons.
I always took at as a drug thing from the context of the digs. "Jane, where's my lithium?" in that one Billionaire Ted skit stands out, as does a Vince media interview from that period where he seemed like he was framing it as a drug thing (I think the word "abuse" may have been used).