Dissociative disorders (DD) are conditions that involve significant disruptions and/or breakdowns "in the normal integration of consciousness, memory, identity, emotion, perception, body representation, motor control, and behavior." People with dissociative disorders also use dissociation as a defense mechanism involuntarily. The individual experiences these dissociations to protect themselves from traumatic stress. Some dissociative disorders are triggered by significant psychological trauma, though depersonalization-derealization disorder may be preceded by lesser stress, psychoactive substances, or no identifiable trigger at all.The dissociative disorders listed in the American Psychiatric Association's DSM-5 are as follows: Dissociative identity disorder (DID, formerly multiple personality disorder): the alternation of two or more distinct personality states with impaired recall among personality states. In extreme cases, the host personality is unaware of the other, alternating personalities; however, the alternate personalities can be aware of all the existing personalities. Dissociative amnesia (formerly psychogenic amnesia): the loss of recall memory, specifically episodic memory, typically of or as a reaction to traumatic or stressful events. It is considered the most common dissociative disorder amongst those documented. This disorder can occur abruptly or gradually and may last minutes to years. Dissociative fugue was previously a separate category but is now treated as a specifier for dissociative amnesia, though many patients with dissociative fugue are ultimately diagnosed with dissociative identity disorder. Depersonalization-derealization disorder (DpDr): periods of detachment from self or surroundings which may be experienced as "unreal" (lacking in control of or "outside" self) while retaining awareness that this is a feeling and not reality. Individuals often show little emotion, report "out of body" experiences, distorted perceptions of their environment (fuzziness, blurriness, flatness, cloudiness), difficulty feeling emotions, difficulty recognizing familiar things, including one's own reflection in a mirror. They may see objects as larger or smaller than the actual size. They may lose certain bodily sensations like hunger and/or thirst. Many patients experience these symptoms continuously everyday while others experience the above symptoms in discrete episodes lasting 1+ hours. The DSM-IV category of dissociative disorder not otherwise specified was split into two diagnoses: other specified dissociative disorder and unspecified dissociative disorder. These categories are used for forms of pathological dissociation that do not fully meet the criteria of the other specified dissociative disorders; or if the correct category has not been determined; or the disorder is transient. Other specified dissociative disorder (OSDD) has multiple types, which OSDD-1 falling on the spectrum of dissociative identity disorder; it is known as partial DID in the International Classification of Diseases (see below).The ICD-11 lists dissociative disorders as: Dissociative neurological symptom disorder Dissociative amnesia Dissociative amnesia with dissociative fugue Trance disorder Possession trance disorder Dissociative identity disorder [complete] Partial dissociative identity disorder Depersonalization-derealization disorder Source: Wikipedia (en)