why should the DSM-IV-TR need both categories of Dissociative Amnesia and Dissociative Fugue

4 answers

They are two different disorders.

http://my.clevelandclinic.org/disorders/dissociative_disorders/hic_dissociative_fugue.aspx

http://my.clevelandclinic.org/disorders/dissociative_disorders/hic_dissociative_amnesia.aspx
so maybe because the symptoms vary and the amount of episodes in inability to recall information
Do they respond to the same or different treatments?
dissociative fugue help the person come to terms with the stress or trauma that triggered the fugue

dissociative amnesia to relieve symptoms and control any problem behavior