These three disorders might perhaps be best understood as variants of complex post-traumatic stress disorder, each deriving its characteristic features from one form of adaptation to the traumatic environment.
Herman argues that somatization disorder, borderline personality disorder, and multiple personality disorder are not discrete nosological entities but adaptive variants of a single underlying trauma-driven pathology.
, Trauma and Recovery: The Aftermath of Violence—From Domestic Abuse to Political Terror, 1992thesis