The Collaborative International Dictionary of English v.0.48:

hag-ridden \hag"-rid`den\, hagridden
\hag"rid`den\(h[a^]g"r[i^]d`d'n), a.
   Ridden by a hag or witch; hence, afflicted with nightmares;
   tormented or harassed by nightmares or unreasonable fears.
   --Beattie. --Cheyne.

   Syn: tormented.
        [1913 Webster + WordNet 1.5]

              hagridden . . . by visions of an imminent heaven
              or hell upon earth                  --C. S. Lewis

WordNet (r) 3.0 (2006):

hag-ridden
    adj 1: tormented or harassed by nightmares or unreasonable
           fears; "hagridden...by visions of an imminent heaven or
           hell upon earth"- C.S.Lewis [syn: hag-ridden,
           hagridden, tormented]