I heard about a strange dream from my friend where she found her entire body (below neck) sort of tied, so that she cant move her limbs and trunk. And she feels really uneasy and screams but it is heard only as a little merely audible to the person sleeping next to her. She requests everybody to wake her up as soon as they sense this happening. It occurs repeatedly. And as I have observed, it occura mostly on days when she was sad or depressed by something!Anybody have any clue? Is this some disorder?