Byline: Claudio. Banzato In a way, the current state of affairs would surpass Stengel's best expectations in the late fifties as internationally adopted classifications (ICD/DSM) have indeed become psychiatry's 'common language'. However, by ignoring Stengel's proviso that read 'it [an international classification] must be a servant of international communication rather than its master', we seemingly ended up with an ICD/DSM supremacy.[sup] [1] Internationally adopted classifications have not only become lately the rulers of communication, but also have shaped psychiatric clinical practice, professional education and research programs to a great extent. As high hopes were placed in such a move for a myriad of legitimate reasons, one should inquire about its actual payoff. Perhaps a major disappointment to date with current classificatory systems is the fact that most of their diagnostic categories simply failed to be validated, either by the discovery of specific etiologies (or pathophysiologic pathways)[sup] [2] or by a robust convergence of independent indicators.[sup] [3] As it turned out, validators, contrary to early beliefs, do not appear to be monolithic.[sup] [4] Accordingly, the causation of mental disorders is most likely a multifactorial process, which means we have to account for many factors from different sorts (each one itself with somewhat weak causal influence) that interact within very complex etiologic networks.[sup] [3],[5] Regarding psychiatric epidemiology, there were obvious gains in the last decades.[sup] [6] Data on the prevalence of mental disorders worldwide have become available. Though comparison across countries and regions may not be fully granted due to issues related to the still uncertain cultural sensitivity (and meaningfulness) of the current diagnostic tools, the estimate rates obtained so far have played an important role in the development of mental health policies. In addition, sophisticated epidemiological methods have been conceived to inform the revision of current diagnostic systems by testing the assumption of the existence of discrete entities and by helping us to select optimal cut-points for defining diagnostic criteria.[sup] [7] It should be noticed that although most criteria sets in ICD-10 and DSM-IV are similar, very few actually coincide. Sorting out meaningful differences from the insignificant ones is a necessary step for the empirical comparative testing of the key options made by each system.[sup] [4] The consequences of the current diagnostic systems on clinical practice and on teaching and training psychiatry are possibly harder to assess. On the up side, it is usually agreed that they have contributed to strengthen the medical identity of psychiatry and to demystify psychiatric diagnosis to some extent, which may have led to a reduction in the stigma associated with mental disorders.[sup] [6] With regard to adverse outcomes, several points have also been made, among them the conflict between clinical and research goals[sup] [8] and the fact that they are often used in a cookbook fashion. Thus, it would be fair to try to separate which untoward effects are due to the intrinsic problems of such systems from those secondary to their simple misuse, even though such sifting may eventually prove unwarranted. Perhaps it would be interesting to make a further distinction (that cuts across the former one) between problems related to the classificatory scheme (taxonomy) and problems related to the diagnostic guidance provided (diagnostic model at their core). The inflation of the comorbidity rates has been probably the most controversial consequence of present classifications. But it has now become clear that such inflation occurred largely at the expenses of artifactual co-morbidity, a by-product of the (predominantly, because it does not apply across all categories) splitting strategy adopted in DSM and ICD.[sup] [4] It should be added that exclusion criteria were meant to counterbalance this trend, but because they were stipulated (not based on empirical grounds); the nosological hierarchy built-in into the system was not warranted. …