Is feeling of deja vu due to some illness?

Q: What causes deja-vu (the experience of perceiving a new situation as if it had occurred some time in the past)? Could such a feeling be a sign of mental, emotional or physical disorder in the person or any deficiency?

A:Many people have a deja vu experience occasionally; more often when under stress. In and of itself, it is not a sign of an illness.