Oops, I think I'm seeing the issue and it is indeed my error.  Somehow I missed that the epidemiology section had a second section regarding comorbidity in it.  I have struck my comment above, and in the future I won't mention it again unless it's relevant to acknolwedge my previous error.  My apologies.
I would argue however that "incidence", which relates to new appearances of DID in the community at large, isn't a good subheading because the section includes a discussion of both incidence and prevalence.  I suggest using a subheading with both (==Incidence and prevalence==) though another option is simply leaving it as epidemiology.  The WP:MEDMOS#Diseases or disorders or syndromes doesn't give much guiance here bar noting that ==Epidemiology== should include incidence and prevalence information; no mention of subsections.  Usually you leave it as a single larger section until it gets sufficiently lengthy that it makes sense to split them out (which is itself dependent on the sources).  I've replaced the section heading (but both I and P).  The section overall needs fleshing out with more sources, which I think are unfortunately lacking.  Searching on pubmed for DID and both incidence and prevalence turns up no articles specifically focussed on either topic.   (t) (c) Wikipedia's rules:simple/complex 
Again, my apologies for the error, the fault was completely mine.