Pierre Janet's works on conversion disorders or dissociative disorders has mainly fallen to the wayside in favour of Freud's works. In the first part of this paper, Janet's conception of hysteria is discussed and his place in French psychiatry described. Different aspects of Janet's diathesis-stress approach are presented (particularly the pathogenic concept of fixed ideas), which refer not only to a conception of hysteria but also to traumatic (stress) disorders and other psychological disturbances. The second part of the paper details the varieties of Janetian therapeutic treatments of these disorders: the "liquidation" of fixed ideas by hypnosis and suggestion, confrontation techniques, which resemble contemporary cognitive behavioural approaches, and special cognitive ("logagogic") interventions. Finally, we discuss the various treatment strategies based on psychoeconomic considerations such as physical or psycho-phyical therapies, psychoeducation, treatment through rest, and simplification of life for dealing with basic disturbances of psychic disorders.