Dissociation is repression of memory and emotion in order to protect the mind from breaking down during, and after, traumatic events. Emotional shock is but one effect. Common causes of the several dissociative disorders are abuses physical and/or sexual, emotional, psychological, including being witness to or victimized by an accident, crime, act of war or nature. Any of these are capable of inducing trauma. The action of dissociating occurs through separating, or fragmenting, thinking from feeling. A single event is enough to induce the disorder. It has been noted that dissociation is a normal response to an abnormal incident, and is deeply rooted in our survival instinct.
Non-serious, or "mild," dissociative experiences are not uncommon, and are reported by nearly 35% of surveyed people. They describe a sensation of detachment, as if acting in a movie. This passing condition occurs mostly to young people, and usually fades around age 20. Seven percent of any given population probably have had a dissociative disorder, but these by nature are difficult to clearly identify.
A person can experience either of two forms of dissociative amnesia. With retrograde, they cannot recall the past from some arbitrary point, but can compose new memories. Anterograde, or "moving forward," disables formation of new memories but doesn't affect those prior to the amnesia's onset. A dissociative fugue results in losing the sense of personal identity in reaction to some environmental stressor or danger. Someone in a fugue state can be called by their name, and not recognize it. The condition may last a few hours, or several days, during which the individual might seek a new job, residence, or love interest. Upon recovering their identity, the person will not recall events and behavior from the fugue state.
Dissociative identity disorder, once known as multiple personality disorder, is the most problematic and rare manifestation. DID surfaces in people who have suffered lacerating physical and/or sexual abuse in their youth. So profound is the anxiety and terror provoked by trauma, the integrated personality splits and forms an "alternate" to cope with day-to-day life. Psychiatric accounts and popular media chronicle victims with more than two personalities, but some mental health professionals remain skeptical and speculate that people presenting DID symptoms are tainted by popular culture, hence "acting out."
Careful, detailed clinical assessments can usually result in proper diagnosis. Dissociative disorders have been found to be more prevalent than most psychiatric disorders, and even a minimal patient interview should cover questions regarding fugue states (popularly known as "missing time"), feelings of unreality or profound strangeness, identity confusion, and changes in everyday behavior and perceptions.
Treatment, commonly ongoing psychotherapy for long-standing dissociative experiences, demands utmost professionalism and sensitivity. Since the patient generally projects suspicion and even paranoia onto the world and its events, trust must be cultivated. A DID-specific medication has not been formulated, but psychiatrists may prescribe any of the existing drugs for generalized anxiety, or even an anti-psychotic medicine, in order to manage symptoms.