Recognizing that the definition as then formulated wasn't working but uncertain how to fix it, the compilers of DSM-IV (1994) dumped PAPD from the list of official disorders and relegated it to an appendix. The most telling complaint, in my opinion, was that merely being passive-aggressive isn't a disorder but a behavior--sometimes a perfectly rational behavior, which lets you dodge unpleasant chores while avoiding confrontation. It's only pathological if it's a habitual, crippling response reflecting a pervasively pessimistic attitude--people who suffer from PAPD expect disappointment, and gain a sense of control over their lives by bringing it about. Some psychiatrists have suggested that PAPD be merged into a broader category, called negativistic personality disorder. Diagnostic criteria: passive-aggressive plus (a) mad at the world, (b) envious and resentful, (c) feels cheated by life, and (d) alternately hostile and clingy.
(Borrowed from this week's Straight Dope column, http://www.straightdope.com)