DISSOCIATIVE DISORDER
When a person experiences a disconnection or lack in thoughts, surroundings, memory, actions and identity, it's known as a dissociative disorder. This disorder usually develops as a reaction to trauma and helps keep difficult memories at bay.

Dissociative disorders usually develop as a way to cope with trauma. The disorders most often form in children subjected to long-term physical, sexual or emotional abuse or, less often, a home environment that's frightening or highly unpredictable.
Personal identity is in its formative years during childhood. So a child is more able than an adult to step outside of himself or herself and observe trauma as though it's happening to a different person. A child who learns to dissociate in order to endure a traumatic experience may use this coping mechanism in response to stressful situations throughout life.
People who experience long-term physical, sexual or emotional abuse during childhood are at greatest risk of developing dissociative disorders. Children and adults who experience other traumatic events, such as war, natural disasters, kidnapping, torture, or extended, traumatic, early-life medical procedures, also may develop these conditions.
Types of dissociative disorders
Dissociative amnesia
The main symptom of dissociative amnesia is memory loss which is more severe than normal forgetfulness. One can't recall information about themselves or events and people in their life, especially from a traumatic time. Dissociative amnesia can be specific to events in a certain time, such as intense combat or more rarely, can involve complete loss of memory about oneself. It may sometimes involve travel or confused wandering away from one’s life - also known as dissociative fugue. An episode of amnesia usually occurs suddenly and may last for minutes, hours or rarely, months or years.

Dissociative identity disorder
Also known as multiple personality disorder, dissociative identity disorder is associated by "switching" to alternate identities. One may feel the presence of two or more people talking or living inside their head, and one may feel as though they're possessed by other identities. Each identity may have a unique name, personal history and characteristics, including obvious differences in voice, gender, mannerisms and even such physical qualities as the need for eyeglasses. There also are differences in how familiar each identity is with the others. People with dissociative identity disorder typically also have dissociative amnesia and often have dissociative fugue.
Depersonalization-derealization disorder
This disorder involves an episodic sense of detachment which involves observing one’s own actions, feelings, thoughts and self from a distance as though watching a movie. Other people and things around one may feel detached and foggy or dreamlike, time may be slowed down or sped up, and the world may seem unreal. One may experience depersonalization, derealization or both.

Symptoms
Broadly, the symptoms can include-
Memory loss (amnesia) of certain time periods, events, people and personal information
A sense of being detached from yourself and your emotions
A perception of the people and things around you as distorted and unreal
A blurred sense of identity
Significant stress or problems in your relationships, work or other important areas of your life
Inability to cope well with emotional or professional stress
Mental health problems, such as depression, anxiety, and suicidal thoughts and behaviors
People with dissociative disorders are at increased risk of complications and associated disorders, such as:
Self-harm or mutilation
Suicidal thoughts and behavior
Sexual dysfunction
Alcoholism and drug use disorders
Depression and anxiety disorders
Post-traumatic stress disorder
Personality disorders
Sleep disorders, including nightmares, insomnia and sleepwalking
Eating disorders
Physical symptoms such as lightheadedness or non-epileptic seizures
Major difficulties in personal relationships and at work
TREATMENT
Psychotherapy
Psychotherapy is the primary treatment for dissociative disorders. This form of therapy, also known as talk therapy, counseling or psychosocial therapy, involves talking about your disorder and related issues with a mental health professional. The therapist will work to help you understand the cause of your condition and to form new ways of coping with stressful circumstances.

Medication
Although there are no medications that specifically treat dissociative disorders, doctors may prescribe antidepressants, anti-anxiety medications or antipsychotic drugs to help control the mental health symptoms associated with dissociative disorders.