Research or Clinical Assessment Tool somatoform dissociation questionnaire true SDQ-20 The 20-item Somatoform Dissociation Questionnaire evaluates the severity of somatoform dissociation. The SDQ-20 items were derived from a pool of 75 items describing clinically observed somatoform dissociative symptoms that in clinical settings had appeared upon activation of particular dissociative parts of the personality and that could not be medically explained. The items pertain to both negative (e.g., analgesia) and positive dissociative phenomena (e.g., site-specific pain). https://www.ncbi.nlm.nih.gov/pubmed/24861272