Nightmares
You are tormented each night by horrible nightmares. Sometimes they're so harrowing that they affect your efficiency during waking hours. Make a self-control roll each morning upon awakening. If you fail, you suffered nightmares; this costs you 1 FP that you can only recover through sleep. On a roll of 17 or 18, you are left shaking, and are at -1 to all skill and Perception rolls for the entire day.
These nightmares can be so vivid that they're indistinguishable from reality. The GM might choose to play them out in the game, starting out like a normal scenario and steadily becoming more horrible. The victim should only gradually come to suspect that he is dreaming. Such dreams can have a dramatic effect on the dreamer's waking life, such as temporary Obsessions or Phobias, or even a psychosomatic loss of HP or attribute levels.
If other PCs are involved in the nightmare, they're completely unaffected by anything that occurs there (but if the nightmare takes a long time to play out, the GM might wish to reward the players with a bonus character point as a token of appreciation for their time – maybe two points if they roleplayed the dream-situation particularly well). It's the GM's option whether to let the other players know in advance that the scenario is a dream. Either way can lead to unique and fascinating roleplaying.