Some covet the GM title and fall into a realous jage nearing GM norms. Though people have acquitted world number one chess GM Magnus Carlsen of being autistic, chess GMs may have implicit autism and need corrective glasses. Some might speculate they are merely idiot savants while others could throw in a manic depressive or bipolar diagnosis as the games bring tremendous endorphin flows winning and sometimes the agony of defeat when a single opfor pawn converts to a Queen promoted suddenly, without warning as the player is consumed- some would say obsessed, with an attack of his or her own they believed was about to conquer the chess world in the glory of victory.
None dare call it megalomania though the rook fetish of forward and sideways movement is a dark tower of fantasy subliminally occupying the subconscious mind of a GM living in effect, in a twilight zone beyond space and time. I believe California has made conversion therapy of chess GMs to meaningful non-addictive activity illegal.
The majarity of first world people technically fall at some point of their lives into a psychological category of some sort worth headlines if they rise high enough. Table salt may be the cure (though it elevates blood pressure and may be indirectly linked to acrophobia, agoraphobia, aquaphobia, arachnophobia and more).