Dissociative disorders have been previously subsumed under the diagnostic construct of hysteria, which has been described the occurrence of various unexplained medical symptoms, without evidence of tissue pathology that can adequately or solely account for the symptoms. Typically dissociative symptoms include paralysis, abnormal movements, inability to speak, blindness, deafness, pseudoseizures, memory loss and detachment from one’s own mental processes, body or environment. According to the current (fifth) edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) the essential feature of dissociation is a disruption of the normal integrative functions of consciousness, memory, identity and perception of the environment. Over recent years researchers have proposed to name the latter manifestations of dissociation psychological dissociation. Clinical observations also indicate that dissociation can manifest in somatoform ways, which is called somatoform dissociation. Although somatoform disorders are not conceptualized as dissociative disorders in the DSM-V, the strong correlation between dissociative and somatoform disorders indicates that dissociation and particular somatization symptoms may be manifestations of a single underlying principle. Moreover, the International Classification of Diseases, Tenth Edition includes somatoform dissociation within dissociative disorders of movement and sensation. Somatoform dissociation designates dissociative symptoms that phenomenologically are related to body, and psychological dissociative symptoms are those that phenomenologically involve psychological variables.
