Dissociative disorders are mental disorders in which dissociation is the central feature that causes significant distress and/or impairments in important areas of life. Both the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and the International Classification of Diseases (ICD-11) recognize depersonalization derealization disorder, dissociative amnesia with or without diagnostic fugue, and dissociative identity disorder as dissociative disorders and provide additional categories for unspecified or other specified dissociative disorders. The ICD-11 includes a dissociative neurological symptom disorder for medically unexplained neurological symptoms that were formally classified as conversion symptoms. The DSM-5 renamed conversion disorder to functional neurological symptom disorder which is placed in the separate category of somatic symptom disorders. It is increasingly recognized that pathological dissociation occurs not only in dissociative disorders but also in a variety of other mental disorders, including borderline personality disorder (BPD) and post-traumatic stress disorder (PTSD). Phenomenological overlap and frequent co-occurrence of these disorders with dissociative disorders can complicate the diagnostic and therapeutic process.