If there's an origin for Psionic ability in fiction it would have to be genetics.Really? Lots of psionic characters in Marvel and whatnot are not particularly smart or strong personalities - Psylocke comes to mind. Not a character I would associate with that and since she's a mutant - Aberrant bloodline in other words - doesn't she fit the bill? And, note, Jedi, the typical go to for D&D psionics are not based on brain or personality but, simply winning the Mitichlorian lottery - effectively an Aberrant bloodline.
The notion of your Int, Wis and/or Cha raising your chances of being psionic seems pretty much a D&Dism more than something you find in fiction.
So really there should be a separate ability score "Power" which can be used for Psionics (and probably for Sorcerer's to).
There won't be, for obvious reasons, so the go to for this kind of thing is usually Charisma (as the formely mostly useless ability as much as anything). However, we've now reached the point where absolutely everyone is croweded around the Charisma corner.