His false sense of zen seems to come and go with his mania, further proof that he's probably bipolar. His last twitter tirade seemingly followed a drinking binge which likely incited another manic episode.
I'd be cautious with terms like bipolar etc, at least in the medical sense.
We have two scenarios here: He is still experiencing the driving part of his medication, which he either quit cold turkey(very bad) or took irregulary( even worse). To me, this is the most likely part, depending on the timeline of his 'self-imposed' treatment. Furthermore, keep in mind that even Alcohol or other substances are available, to agitate his state.
So it wouldn't be completely unheard of, that he drank a bit before recording, for example.
Now a very unlikely case is that he is truly bipolar by the medical definition or that his medication troubles in conjunction with his downward spiral 'awakened' a bipolar disorder.
We only see a small window of mumkeys full person and also receive no reports of his symptoms like his doctor does, but to me, his speech patterns aren't frantic enough, his thought process aren't disorderly enough and his depressed states (the ones we are privy to) aren't too severe.
If I would hazard a guess, then I'd say he would land on the anxiety spectrum. It is evident that he doesn't think highly of himself, but even utterly despises himself, thinks he'll be alone forever.
The whole grandeur, savior talk, comparison to super heroes etc. is just someone with severe anxiety trying to cope. Remolding the image he hates, destroying it even, to create a new one. That's why we get walter white tyler, black widow tyler, buddha tyler, jesus tyler...
Furthermore, his screaming at the end isn't genuine in that he is truly pissed, but if you look into his eyes and facial expressions, it feels more like a feeling of hurt, desperation, like a small animal doing a threat posture, especially how he presses his voice in a controlled manner. It's like a 10 yr old putting on a deeper voice to come off more edgy.
We have seen this pressed/loud voice occur a lot in the current saga, and I think that it supports my hypothesis, that he literally tries drown out his fears with volume the same way he repeats the 'I'M OKAY-Mantra' or his fake 'wise beyond years-Attitude' despite being thin skinned as ever, regarding his approach to 'mean comments' that hit too close to home.
Now throw in some pills that he shouldn't have gotten in the first place, at least that easily, that he decided to quit cold turkey or takes irregulary and you got the perfect recipe for an extremely volatile person, ready to lash out, bursting into fits of crying or self-aggrandizing thoughts, rage etc since his hormones were put in a blender, on top of his pre-existing anxiety problems, self image, emotional maturity of a 13-15 yr old.