The current findings have implications for traditional conceptions of mental disorders as discrete, etiologically coherent entities. In line with findings from previous structural modeling studies [1-3], common mental disorders were found to co-occur reliably in distinctive patterns, consistent with the idea of shared etiologic underpinnings to differing disorders [37, 38]. As noted above, however, for the four comorbid classes in both the NCS and NCS-R, heightened rates of disorders characteristic of other classes were also evident, with one particular set of disorders (i.e., depression, social phobia, and PTSD) elevated across classes. Although somewhat speculative, this raises the possibility that mechanisms governing manifestations of particular disorders vary according to what class they occur in – i.e., as a function of the overall pattern of affiliated comorbidity.
