Our practice, in a unit of treatment of dysthymic state being confronted with problems of relapses and recurrences, we have questioned the therapeutic strategies in the long run and their possible assessments. After recalling conceptual and methodological reference about relapses, recurrences and therapeutic assessment, we propose the methods and first results of a retrospective naturalistic study over a period of three years of practice in our treatment unit including 994 cases. We bring out, as soon as the first major depressive episode occurs, a strategy that aims at setting up a therapeutic proceeding tending to treat, beyond the dysthymic episode, the obsessional pre and post-morbid "locks" which seem to "make the bed" of many relapses and recurrences. In this prospect, the interest of serotoninergic molecules with double polarity, anti-depressive and anti-compulsive, is emphasized.