Brave New World Theme of Isolation

Isolation is a tricky bird in Brave New World. On the one hand, it's a painful experience for more than one "unique" character who finds himself at odds with the rest of society. On the other hand, it's a means to self-discovery and spirituality. Because of the latter, solitude is essentially outlawed in the novel's futuristic, highly controlled totalitarian setting.

1. John grew up hating that he was always kept separate from the Indians. But at the end of the novel he desires nothing more than to be alone. What happened to make him do a 180 like this?
2. What is the value of solitude in Brave New World? Is it beneficial or harmful? Is there a general answer to this question, or is it different for one character (let's say, Bernard) than it is for another (for example Helmholtz)?
3. What's the difference between the isolation John faced in the Savage Reservation and the isolation that Bernard is dealing with at the novel's start?

John only "falls in love" with Lenina because she is the first white woman he's seen aside from his mother. He thinks she is the way out of a life of solitude and loneliness.