I was seriously assaulted in broad daylight, in a city park, with no provocation. There were many witnesses and I'd suffered whiplash and a traumatic brain injury. (I feel I have not been the same since.)
The assailant had a 30 year history of paranoia/psychosis and got off any/all charges based upon mental health status. (I was never asked if I was in agreement with the findings; yet, I know the person was psychotic at the time of the assault because of the utterances made during the assault. If I was asked, I would have agreed.)
The assailant was treated, stabilized and released.
This defense may depend upon individual state laws.
I wish you the best.

WC