The majority of depressive disorders may be viewed as a recurrent condition with the possibility of a deteriorative effect on the quality of life and productivity. The results of clinical investigations suggest that anti-depressant medication should be continued for a period of 4-6 months after the acute episode has been resolved (continuation therapy). What is more controversial, however, is the view that patients who have fully recovered should continue to receive medication in an attempt to prevent a future episode from taking place (maintenance therapy). Taking into account the results of empirical investigations which have shown that depressive disorders appear to become more severe and potentially refractory with each new episode, it is argued that patients at risk for recurrent episodes should receive a maintenance pharmacotherapy. The present study reviews the rationale and practical guidelines for the long-term treatment of affective disorders.