Paper underlines basic diagnostic rules, which are used in an assessment of the diagnosis of dependence syndrome in the most frequently used diagnostic classifications: DSM-IV and ICD-10 with focus on changes in clinical picture in the course of time. The diagnostic criteria at the time of the first diagnostic assessment of the patient in his life are not the main issue here, but these are criteria to confirm or to eliminate the diagnosis of dependence syndrome and the course modifiers in the patient, who has already been given medical diagnosis in the past. Important c1inical, health organizational, ethical, social and legal implications of the existence of the possibility to reverse the diagnosis of dependence syndrome on psychoactive substances are mentioned.

Key words: diagnosis – dependence syndrome – course - reversibility – ICD-10 – DSM-IV