a sense of change or unreality in one’s environment that appears in certain mental illnesses (for example, schizophrenia, cyclothymia, epilepsy).
While experiencing derealization, the outside world is perceived as foreign, artificial, changed, and sometimes distant, vague, and dreamlike. Time seems too fast, or else it seems to have stopped. Unfamiliar surroundings seem to have been seen before and, conversely, familiar situations and places seem strange, as though seen for the first time. Derealization is often accompanied by melancholy, fear, and confusion; it is often combined with depersonalization. It is treated by eliminating the primary illness.