Yes. There are many of the DSM-IV diagnoises available on that drop-down list, but not all of them. If you find you have need to add some or change what is there, you have total control.

Select "DSM-IV Codes" off of the Administrative menu.

Scroll to the bottom of the list, and add the new entries in the blank line at the bottom. You can also change anything in any of the other ones, as well.