Jules Séglas (May 31, 1856 – 1939) was a French psychiatrist who practiced medicine at the Bicêtre and Salpêtrière Hospitals in Paris. Early in his career, he was an assistant to famed neurologist Jean-Martin Charcot (1825–1893). Séglas' ideas and theories influenced a number of psychiatrists, including Henri Ey (1900–1977) and Jacques Lacan (1901–1981). In 1908 he became president of the Societé Medico-Psychologique. In the field of psychopathology he conducted studies of delusions, hallucinations and pseudohallucinations, providing a detailed nosology of these phenomena. He did extensive research of language and its relationship to mental illness. Here, he described linguistic traits such as logorrhea, embolalia, near-mutism, automatic speech, alexia, agraphia, et al.; and how these behaviors take shape and interact in various psychiatric disorders.

Selected writings