Dissociative disorders disorders which involve a major dissociation of personal identity or memory. Take on three different forms: selective memory loss. Psychogenic amnesia a person responds to a stressful event with extensive but. Psychogenic fugue a person loses all sense of personal identity, gives up their customary life, wanders to a new faraway location, and establishes a new identity. Triggered by a highly stressful event or trauma. May last from several hours to several years. Dissociative identity disorder two or more separate personalities coexist in the same person. A primary/host personality appears more often than others. Personalities may or may not know of existence of others. Trauma-dissociation theory development of new personalities occurs in response to severe stress. Schizophrenia a psychotic disorder that involves severe disturbances in thinking, speech, perception, emotion, and behaviour. Characteristic of schizophrenia attention, thought, and perception. Diagnosis requires that a person misinterprets reality and exhibits disordered.