What causes a sense of overwhelming dread and deja vu?

Answer 1

The most common health related cause would be anxiety disorder. When someone is under a lot of stress or dealing with depression, these things manifest in many symptoms, derealization (which can cause a sense of deja vu), depersonalization and sense of dread or doom are 3 common symptoms.

On a personal note, my mother has experienced an overwhelming sense of dread only a few times; once when my Dad was attacked in Vietnam and she woke screaming his name, once before my stepdad died and the night before my baby died from Sudden Infant Death Syndrome. Coincidence or psychic sensations? I should mention she has never had anxiety disorder.