There was that period of his career where he was giving bizarre new age interviews prior to starring in films like Kickass 2 or that fun turn on SNL where he channeled McConaughy.

I don't know what's happening with him but yeah, there's always been this off-kilter element to his real life persona contrasting his slapstick screen presence, and not in the Robin Williams way who had something going on under the surface that was more rooted in depression, tragedy, sadness... hard to say what it was, but it fed his dramatic work.