The trance-like state while playing, and eternal smiling are dead giveaways. Plus the loose-fitting, almost pyjama-type stage clothes...that's like totally Buddhist.
Adam's had the way about him for awhile though. I think sobriety brought it out a lot more. I've been watching some concert videos and on stage, he seemed the happiest. Watch clips from Red Rocks if you can find them, that's one happy fella! *Youtube is great for this stuff!*
When asked about their interpretations of what 'All Because of You' could be about:
"All Because of You"
The Edge re-finds the Riff
Clayton: "It could be about God, it could be about your father or your friends. Or the audience."
The Edge: "Life would be so much simpler if you didn't know what you knew. I think it's about that, in a way."--Blender magazine.
I'm a Christian myself, and I'm always wearing loose-fitting clothes, not as nice as Adam's but definitely dress like that...even before getting into U2. I'm all about comfort over what's fashionably 'in.'
There's nothing quite like a comfy pair of cargo pants.
Buddhists don't believe in God though, at least that's what I learned in my religious studies course in college,.
Edge has more of the Zen thing going on, but that's just my .02
"Clayton, who alone has not announced formally for Christianity, says simply that for journalists 'religion was an easy angle, a hook to hang a story on. We all believe in much the same things but don't express ourselves in the same way.' This, along with Clayton's inborn rebellious instincts and up-tempo temperament, caused some intramural tension that has only lately been resolved.
'I was in the wilderness for a few years, so there was a natural antagonism within the band that people picked up on. Now the spirituality contained within the band is equal to all the members.'" Time "Rock's Hottest Ticket"
From Until...World pg. 480
"Do you think that you, Larry, and Edge are still on the same wavelength in your beliefs?" 'What about Adam?' Bono says quickly. 'Adam's the same. I mean, nobody is exactly the same, but Adam's a believer."
"Adam's a believer", coming from Bono, is the closest you get to an answer, unless Adam openly says other wise. For the most part, it's a term specifically relating to Christians. Other religions don't use the term for those who are part of that particular faith. I don't know of any other religions who use that term to its adherents but I could be mistaken.