Current psychiatric nosology emphasizes observable symptoms as the central schema by which mental illnesses should be classified; patients are identified as depressed or schizophrenic by virtue of observed behavior or reported experiences, rather than theoretical underlying causes that may lead to an array of diverse presentations. Within this schema, the diagnosis of posttraumatic stress disorder (PTSD) is somewhat an outlier—its identification relies not only on overt symptomatology, but also the identification of a particular etiology from traumatic moment to current distress. That is, symptoms diagnosed as PTSD not only index that diagnostic category, but also a previous pathogenic trauma. This indexicality is bolstered by an act of rhematization, the transformation of indexical relationships into iconic links, whereby PTSD symptoms are understood as resembling a pathogenic trauma, thus distinguishing PTSD from disorders whose presentations carry no such resemblance to trauma.
"Rhematization as Etiology in the Diagnosis of Posttraumatic Stress Disorder,"
Colorado Research in Linguistics: Vol. 24.
Available at: https://scholar.colorado.edu/cril/vol24/iss1/6