well to begin with i don't think anyone should be locked up in mental ward
for experinces of this sort it's quite common
sleep paralysis often accompanied with some morbid visions
dark figures on the side of bed or leaving the room
even partners of suffering individual has been reported to see things
and sleep paralysis is kinda of spiritual thing too ( from my opinion )
i once recall having bad sleep paralysis and kept trying to shout
for some one to wake me up ( was aware i was sleeping )
and it resulted in those groans which i could hear coming from me
as for marks or scratches on back could be skin rash due to the rush or fear
it could be an attack too but i find it fit to rule out common causes first
and most sleep paralysis occur in that certain age between 15-22 or so
i hope they stop soon whatever they may be
and she find out what the cause
although just stopping is good enough without knowing any cause