In Bakhtin’s Problems of Dostoevsky’s Poetics, Bakhtin writes of how Dostoevsky invented the polyphonic novel, where several consciousnesses simultaneously coexist, even if their ideas are contradictory. Bakhtin argues that D does this is a dialogical manner, rather than bringing the ideas together under a monological development. He cites Kirpotin on what Bakhtin calls D’s “special ability to see precisely the soul of others” and what Kirpotin calls D’s “capacity to visualize directly someone else’s psyche.” Kirpotin says of D that "His world is the world of a multitude of objectively existing and interacting psychologies, and this excludes from his treatment of psychological processes the subjectivism and solipsism so characteristic of bourgeois decadence."
It might not be that hard for a writer to write a fairly narcissistic story about one individual's psychological struggles. The reason is that each writer is an individual, and every individual has experience with individual psychological struggles. A skilled and insightful human being like Dostoevsky has the ability to not write a solipsistic novel, but to examine different people, different psychological struggles. In The Brothers Karamozov he gets into the heads, I mean really, really gets into the heads, of Alyosha, Ivan, and Dmitri. Three different characters with different issues, and he presents not their narcissistic struggle, but their interactions with the world and with each other in facing these struggles.
Of course, a postmodern writer like John Fowles openly admits, within his novels, that he is incapable of penetrating the souls of his characters (see chapter 13 of The French Lieutenant’s Woman).
But I see a fair amount of good writers really writing these solipsistic stories of an individual (at the very least, narcissistic). Often they show real skill in the writing. But I'm not sure it shows a great deal of insight, since, as I said, any reflective individual knows of the solipsistic emotional, spiritual, intellectual, psychological struggle. A true genius penetrates outside of that and into others.
Bakhtin also notes that a dialogical, polyphonic novel exists over space rather than time. It contrasts to Hegelian evolution in that it does not monologically develop an idea, even dialectically—contradictory ideas exist in different consciousnesses without being resolved. Some modernists, I think, picked up on Dostoevsky’s dialogism and wrote what could be called polyphonic works of literature. In Faulkner’s works, for example, we see multiple voices, and multiple ideas, coexisting, and I don’t think Faulkner tries to resolve these voices monologically.
But I’m really simplifying Bakhtin here, and perhaps bastardizing him, and most surely making his ideas confusing, so perhaps you should just read Bakhtin’s Problems of Dostoevsky's Poetics, or at least the first chapter, “Dostoevsky’s Polyphonic Novel and Its Treatment in Critical Literature.”
Other works I’m thinking about in light of Bakhtin’s theories:
Roth’s Sabbath’s Theater
When reading this novel, I thought it suffered from a lack of an objective correlative; Sabbath’s inability to cope with loss was not matched with any loss in his life that is atypical of human existence. Another problem is the narcissism. The book doesn’t attempt to penetrate anything other than one man’s totally narcissistic problems. Perhaps this novel is the epitome of the anti-Dostoevskian novel.
Sartre’s The Age of Reason
On the one hand, this is a dialogical novel—it’s a book of ideas, and ideas are held by different consciousnesses, and they seem to coexist and interact. On the other hand, it’s a dialectically evolving monological novel. Sartre the existentialist guides the novel, and for the most part it conforms to his individual worldview. He doesn’t, as Dostoevsky, allow his ideas/consciousnesses to coexist without resolution; he uses these different ideas/consciousnesses to develop his monological ideas.