Dostoyevsky's characters and their maladies

Part 2 of Fyodor Dostoyevsky's "The Idiot" gets off to a bit of a slow (for him) start, as Myshkin, returned to Petersburg after some time in Moscow claiming his inheritance and refashioning himself as a new man (but not at all changed emotionally or psychologically)visits several Petersburg acquaintances, notably the two he met on the train in the first chapter of the novel: Rogozhin and Lebedev. His real interest is in Nastasya, whom we learn had been involved in various tempestuous episodes with Rogozhin in Moscow, and now has apparently vanished to a dacha outside of Petersburg. It's not entirely clear to me why Myshkin is visiting Lebedev and Rogozhin, but I think his main motive is he wants to clear the air before making any supplication to Nastasya: he would never pursue her unless he knew that Rogozhin was out of the picture. This section of the novel is a little less dramatic because the scenes of Nastasya's mania and Rogozhin's obsession are described rather than dramatized before us - like the great scene of N.'s birthday party that concludes Part 1. Still, Dostoyevsky gives a great description of Rogozhin's squalid Petersburg digs, and he builds the conversation between R. and the Prince to one dramatic moment: when Rogozhin informs Myshkin of what all readers already know - that Nastasya, inexplicably, is in love with him (the Prince). The novel, from here forward, will concern what the Prince does with that information: he is, as he noted in the first chapter, completely ignorant when it comes to women, and Nastasya is a dangerous and self-destructive woman - so how the two of them approach each other will be quite a scene I would guess. How do we characterize them? Today, we'd probably say that N. suffers from bipolar disorder, with her extreme mood swings and self-abasement and self-destructive behavior and inability to commit, plus had a history of childhood abuse. And the Prince? Perhaps today we would find him somewhere on the autism spectrum - his literal-mindedness, inability to pick up social cues, and incapacity for self-censorship.