Although some dissociative disruptions involve amnesia, the vast majority of dissociative events do not. Since dissociations are normally unanticipated, they are typically experienced as startling, autonomous intrusions into the person’s usual ways of responding or functioning. Due to their unexpected and largely inexplicable nature, they tend to be quite unsettling.
Different dissociative disorders have different relationships to stress and trauma. Dissociative amnesia and fugue states are often triggered by life stresses that fall far short of trauma. Depersonalization disorder is sometimes triggered by trauma, but may be preceded only by stress, psychoactive substances, or no identifiable stress at all.