Kathy Steele, cocreator of the Structural Dissociation Theory, patiently defends the existence of Dissociative Identity Disorder to Ira Flatow and Numan Gharaibeh (a clueless psychiatrist) on NPR's Science Friday. Worth a listen: http://www.sciencefriday.com/program/archives/200911133 

I've run into this blindness before, mostly in analytically trained psychiatrists, despite all evidence.