I don't think he tries to hide it at all. He's talked openly about it for as long as I've been following the band.

Recently, over the last couple of years especially, there have been a lot of erratic performances and interviews; and it could very well be because Richie's in over his head with substance abuse again. Because of his history that's everybody's first guess, just like people first assumed he was in rehab when he didn't show up in Calgary. But just like then, there could also be some things going on that we're not aware of, other than, or in addition to, his addictions.