Pierre Marie Félix Janet (1859-1947), born in Paris, came from an established upper-middle class family. He studied philosophy at the highly selective École Normale Supérieure, and his uncle, the philosopher Paul Janet, encouraged him to also study science and medicine. His doctoral thesis investigated the topic of hallucinations and hypnotic phenomena. The findings of his first studies of Léonie, a hypnotic subject in her youth, attracted much attention when presented in 1885 and he successfully defended his thesis in 1889. Janet was then took up a teaching position whilst also enrolling as a medical student and conducting research, mainly under the guidance of Charcot. After graduating, his appointments included director of a new experimental psychology laboratory at La Salpêtrière hospital, then director of studies in experimental psychology at the Sorbonne, and until his retirement in 1935 professor of experimental and comparative psychology at the Collège de France.
His research investigated hysteria and what are now termed anxiety states, phobias and obsessional disorders. He published two important books that introduced terms such as 'dissociation' and 'narrowing of the field of consciousness' which are used today, and his ideas influenced both Jung and Adler. Janet proposed a psychological system that sought to explain both normal and abnormal behaviour from childhood to old age. As individuals develop they move up a hierarchy of progressively more complex levels of organization. Abnormal behaviour and neurotic states resulted from a failure to integrate the 'tendencies' associated with a level and individuals may regress or be fixated at an earlier stage. Unfortunately, much of his work was not translated into English and Janet has not received the recognition he deserves. There has been some renewed interest in his work following the awareness of child abuse and the acknowledgement of post-traumatic stress syndromes, as Janet proposed that traumatic events could result in dissociation or hysteria and that the symptoms could be alleviated by bringing the memories and feelings associated with these events into consciousness.