[What should be the duration of a treatment with antidepressive agents?].

The main clinical factors involved in deciding the length of an antidepressant treatment are briefly reviewed in the framework of current classifications of affective disorders. History of previous episodes and the polarity of depressive illness have a major role in such a process. Current definitions of remission, relapse and recurrence are given. In the context of a single depressive episode, treatment must be continued for at least 4 months after the start of clinical improvement in order to prevent a relapse. In case of recurrent depressive episode, the indications of a long-term treatment must be discussed. Some issues unsettled as to the adequate dosage of such a treatment, as well as to the length of treatment in other types of depressive states.