Andrew Brown remarked about VN's mature writing of Pale Fire, as a contrast to his adolescent infantuation with Robert Louis Stevenson's novels. Stephen Blackwell informed us that VN had read William James ( and about "alternate personalities") while still 12-14 years old, almost in the same period of his reading J&H.

Perhaps at the time Nabokov wrote "Pale Fire" he had been able to alter the spirit of his first enthusiasms and turned his admiring, but now critical views, to his novel in a different way. 
Probably, if Nabokov had not objected to the Vienna crowd so openly, I might have mentioned before Freud's  1910/12 article "Psycho-Analytic  Notes upon an Autobiographical Account of a Case of Paranoia ( Dementia Paranoides), Standard Edition, vol. XII. 

In my opinion a lot of what Freud developed about neuroses of defense, mechanisms of projection and the emergence, in Pres. Schreber's material, several homosexual repressed fantasies then associated to paranoia and persecutory delusions,  can also be observed in Charles Kinbote's productions, although the latter is a fictional character and his achievements and destiny differs widely from Shreber's.  

In a former message I referred to Freud's Schreber case and added a wrong date for Melanie Klein's "On Identification".
Her 1946 article is "Notes on Some Schizoid Mechanisms", where Klein studies Freud's Schreber case before describing her own developments about the process of "splitting".
The article I mentioned, "On Identification", was published in 1955, where she advanced her conception of the "inner world" and her innovative concept of "projective identification", using Julian Green's novel "If I were you" as an illustration.

Wikipedia informs: Julien Green was born in 1900, in Paris, a descendant of a Confederate Senator, Julian Hartridge.He was educated at the University of Virginia in the United States from 1919-22. His career as one of the major figures of French litterature in the 20th century started soon after his return from the United States...  A devout Catholic, most of his books focused on the ideas of faith and religion as well as hypocrisy. Several of his books dealt with the southern United States.Thus far three of his books have been turned into films: Léviathan (1962), for which he himself wrote the screenplay, is the most famous. Adrienne Mesurat (1953) and La Dame de pique (1965) are the other two.
Green was the first non-French national to be elected to the Académia française in 1971, as it was commonly believed he had dual citizenship. In fact, although born in Paris and writing in the French language, he had never become a French citizen. His novel was translated from the French by J.H.F McEwen ( London,1950).

Schreber's Memoirs were published first in German, in 1903, by O. Mutze in Leipzig: "Denkwürdigkeiten eines Nervenkranken".

Shade's poem, although it might still have been written if he'd been a psychotic person ( if we should stretch matters a little), doesn't strike me as having been written by someone who suffered from paranoia, in contrast to Kinbote's delusional constructions and special cleverness. 
Jansy