So I was thinking about witches/wizards with two personalities (dissociative personality disorder/multiple personality disorder), and entertained the possibility of them being chosen by two wands. Do you think that it would be possible?
(Similar question "Can a Person Be Chosen By More Than One Wand?" did not specify mental illness, so I think I'm in the clear with this one.)
All cases of wizards with any form of mental disorder, or psychological condition are shown to either not have wands, or to have had their wands taken away. If a wizarding child had multiple personality disorder they would most likely be in St. Mungo's or kept watch in their own homes.
We already know that Wizards can be chosen by multiple wands so adding in multiple personalities doesn't really change this possibility, but it most likely limits the wizard or witch from receiving a wand at all.
Professor Lockhart is locked up as we see here - due to losing his memory
“Listen to him,” said the Healer, taking Lockhart’s arm and beaming fondly at him as though he were a precocious two-year-old. “He was rather well known a few years ago; we very much hope that this liking for giving autographs is a sign that his memory might be coming back a little bit. Will you step this way? He’s in a closed ward, you know, he must have slipped out while I was bringing in the Christmas presents, the door’s usually kept locked . . . not that he’s dangerous! But,” she lowered her voice to a whisper, “bit of a danger to himself, bless him.
Neville Longbottom's parents were tortured to insanity - they share the closed ward with Lockhart and others.
“My son and his wife,” she said, turning haughtily to Harry, Ron, Hermione, and Ginny, “were tortured into insanity by You-Know-Who’s followers.”
Finally, Dumbledore's sister Ariana, who appears to have some form of PTSD (or similar) disorder from being tormented by other children.
They forced their way through the hedge, and when she couldn’t show them the trick, they got a bit carried away trying to stop the little freak doing it.
‘It destroyed her, what they did: she was never right again. She wouldn’t use magic, but she couldn’t get rid of it: it turned inwards and drove her mad, it exploded out of her when she couldn’t control it, and at times she was strange and dangerous. But mostly she was sweet, and scared, and harmless.'
About having more than wand: Yes. At the end of Harry Potter and the Deathly Hallows, Harry Potter had three wands:
His own
Draco Malfoy's
The Elder Wand
And also, Draco Malfoy also had two wands:
About whether a mentally ill person would have two wands: Probably not. They might have a highly volatile wand, if they have a wand at all (I can't imagine that someone in their right mind would take a psycho person to buy a wand), but they probably would not have a wand for each personality.
We do not know. There are no characters shown within canon to have a diagnosed mental condition.
There are a few character we with some signs of mental distress... None of them have their wands.
Frank and Alice Longbottom
Tortured into insanity beyond any cure. They are being treated in St. Mungo's.
Gilderoy Lockhart
Had his entire memory wiped from a backfiring charm. He is being treated St. Mungo's
Ariana Dumbledore
Is suffering from sort of mental distress due to the death of her mother. She was not sent to St. Mungo's, but did not have a wand to begin with.
