Fifth editions: DSM vs. D&D

This month's Psychology Thought Experiment:

At this moment, two groups are at work, each developing the 5th edition of a tool that thousands—perhaps millions—of people rely upon:

One group is creating the 5th edition of the DSM (Diagnostic and Statistical Manual of Mental Disorders).
The other group is creating the 5th edition of D&D (Dungeons & Dragons).

Compare the thought processes of the two groups.

BONUS: Pictured here: images of the fourth edition of D&D and of the DSM.

BONUS: An unrelated work in progress: the band The Fifth Edition

BONUS (equally unrelated): The Fifth Edition sings "Workin' on a Groovy Thing: