|Classification and external resources|
Dissociative disorders (DD) are conditions that involve disruptions or breakdowns of memory, awareness, identity or perception. People with dissociative disorders use dissociation, a defense mechanism, pathologically and involuntarily. Dissociative disorders are thought to primarily be caused by psychological trauma.
- Depersonalization disorder: periods of detachment from self or surrounding which may be experienced as "unreal" (lacking in control of or "outside of" self) while retaining awareness that this is only a feeling and not a reality.
- Dissociative amnesia (formerly psychogenic amnesia): the temporary loss of recall memory, specifically episodic memory, due to a traumatic or stressful event. It is considered the most common dissociative disorder amongst those documented. This disorder can occur abruptly or gradually and may last minutes to years depending on the severity of the trauma and the patient.
- Dissociative fugue (formerly psychogenic fugue): reversible amnesia for personal identity, usually involving unplanned travel or wandering, sometimes accompanied by the establishment of a new identity. This state is typically associated with stressful life circumstances and can be short or lengthy.
- Dissociative identity disorder (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 are aware of all the existing personalities.
- Dissociative disorder not otherwise specified: used for forms of pathological dissociation that do not fully meet the criteria of the other specified dissociative disorders.
Both dissociative amnesia and dissociative fugue usually emerge in adulthood and rarely occur after the age of 50. The ICD-10 classifies conversion disorder as a dissociative disorder while the DSM-IV classifies it as a somatoform disorder.
Diagnosis and prevalence 
The lifetime prevalence of dissociative disorders varies from 10% in the general population to 46% in psychiatric inpatients. Diagnosis can be made with the help of structured interviews such as the Dissociative Disorders Interview Schedule ((DDIS) and the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D), or with the Dissociative Experiences Scale (DES) which is a self-assessment questionnaire. Some diagnostic tests have also been adapted and/or developed for use with children and adolescents such as the Children's Version of the Response Evaluation Measure (REM-Y-71), Child Interview for Subjective Dissociative Experiences, Child Dissociative Checklist (CDC), Child Behavior Checklist (CBCL) Dissociation Subscale, and the Trauma Symptom Checklist for Children Dissociation Subscale.
There are problems with classification, diagnosis and therapeutic strategies of dissociative and conversion disorders which can be understood by the historic context of hysteria. Even current systems used to diagnose DD such as the DSM-IV and ICD-10 differ in the way the classification is determined.
Children and adolescents 
Dissociative disorders (DD) are widely believed to have roots in traumatic childhood experience (abuse or loss), but symptomology often goes unrecognized or is misdiagnosed in children and adolescents. There are several reasons why recognizing symptoms of dissociation in children is challenging: it may be difficult for children to describe their internal experiences; caregivers may miss signals or attempt to conceal their own abusive or neglectful behaviors; symptoms can be subtle or fleeting; disturbances of memory, mood, or concentration associated with dissociation may be misinterpreted as symptoms of other disorders.
In addition to developing diagnostic tests for children and adolescents (see above), a number of approaches have been developed to improve recognition and understanding of dissociation in children. Recent research has focused on clarifying the neurological basis of symptoms associated with dissociation by studying neurochemical, functional and structural brain abnormalities that can result from childhood trauma. Others in the field have argued that recognizing disorganized attachment (DA) in children can help alert clinicians to the possibility of dissociative disorders.
Clinicians and researchers also stress the importance of using a developmental model to understand both symptoms and the future course of DDs. In other words, symptoms of dissociation may manifest differently at different stages of child and adolescent development and individuals may be more or less susceptible to developing dissociative symptoms at different ages. Further research into the manifestation of dissociative symptoms and vulnerability throughout development is needed. Related to this developmental approach, more research is required to establish whether a young patient’s recovery will remain stable over time.
Current debates and the DSM-5 
A number of controversies surround DD in adults as well as children. First, there is ongoing debate surrounding the etiology of dissociative identity disorder (DID). The crux of this debate is if DID is the result of childhood trauma and disorganized attachment. A second area of controversy surrounds the question of whether or not dissociation as a defense versus pathological dissociation are qualitatively or quantitatively different. Experiences and symptoms of dissociation can range from the more mundane to those associated with posttraumatic stress disorder (PTSD) or acute stress disorder (ASD) to dissociative disorders. Mirroring this complexity, it is still being decided whether the DSM-5 will group dissociative disorders with other trauma/stress disorders.
A 2012 review article supports the hypothesis that current or recent trauma may affect an individual's assessment of the more distant past, changing the experience of the past and resulting in dissociative states. However, experimental research in cognitive science continues to challenge claims concerning the validity of the dissociation construct, which is still based on Freudian notions of repression. Even the claimed etiological link between trauma/abuse and dissociation has been questioned. An alternative model states that "dissociation and dissociative disorders are associated with (a) intense objective stressors (e.g., childhood trauma), (b) serious cognitive deficits that impede processing of emotionally laden information, and (c) an avoidant information-processing style characterized by a tendency to forget painful memories."
See also 
- Complex post-traumatic stress disorder
- Dissociative identity disorder in fiction
- Satanic ritual abuse
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- Mayo Clinic - http://www.mayoclinic.com/health/dissociative-disorders/DS00574/DSECTION=treatments-and-drugs
- Cleveland Clinic - http://my.clevelandclinic.org/disorders/dissociative_disorders/hic_depersonalization_disorder.aspx
- International Society for the Study of Trauma and Dissociation - http://www.isst-d.org/
- Sidran Institute - http://www.sidran.org/sub.cfm?sectionID=4