• The diagnostic criteria of the third edition of the DSM-III often state that one diagnosis cannot be made If It is "due to" another disorder. Using data from the National Institute of Mental Health Diagnostic Interview Schedule, with a sample of 11,519 subjects from a community population, we found that if two disorders were related to each other according to the DSM-III exclusion criteria, then the presence of a dominant disorder greatly increased the odds of having the excluded disorder. We also found that disorders, which DSM-III says are related to each other, were more strongly associated than disorders, which DSM-III says are unrelated. However, we also found there was a general tendency toward co-occurrence, so that the presence of any disorder increased the odds of having almost any other disorder, even if DSM-III does not list it as a related disorder. We concluded that empirical studies are needed to study the assumptions underlying the use of a diagnostic hierarchy.
Boyd JH, Burke JD, Gruenberg E, Holzer CE, Rae DS, George LK, Karno M, Stoltzman R, McEvoy L, Nestadt G. Exclusion Criteria of DSM-IIIA Study of Co-occurrence of Hierarchy-Free Syndromes. Arch Gen Psychiatry. 1984;41(10):983-989. doi:10.1001/archpsyc.1984.01790210065008