Harry's pathologies being due to his mother seeking validation through her child’s academic achievements?

Why not? Consider that HJPEV's life history is a major, perhaps the most important point of departure from canon, so this actually makes for a highly parsimonious explanation of his other differences from canon, most relevantly the activity of his Dark soul fragment, the fact that unlike canon!Harry he could not really qualify for House Gryffindor (as revealed by the Sorting Hat) and possibly others.

Keep in mind that Love is freely acknowledged as being the most important magical force in Harry Potter's world, so it stands to reason that an unusual lack of Love, even from adoptive parents, could have very bad side effects. It should be noted that while canon!Harry was also raised by Muggle adoptive parents, and is known to have been severely bullied/punished for his accidental magic, his life was otherwise quite ordinary and not really marked by other kinds of abuse or unusual narcissism.
And there are intriguing analogies between HJPEV's posited childhood as adopted child of narcissist parents, and Tom Riddle's.