When writing a paper, treat the American Psychiatric Association as the institutional author of the DSM-IV. So, the in-text citation should be similar to those for other books.
For example:
The American Psychiatric Association notes that, "Delusions are firmly held erroneous beliefs due to distortions or exaggerations of reasoning and/or misinterpretations of perceptions or experiences" (1994).
When paraphrasing, it should look like this example:
Delusions resort from exaggerated perceptions and distorting thinking (American Psychiatric Association, 1994).
When writing out the reference listing, it should look like this:
American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th Edition). Washington, DC: Author.
The very last word of the citation has to be "author." This word is used this way when an institutional author and a publisher are one and the same.
In 2000, the American Psychiatric Association issued a revised version of the DSM-IV called the DSM-IV-TR. The "TR" stands for "text revision." This is actually the most current edition of the manual. The rule for in-text citation does not change in terms of using parenthetical marks. However, the DSM-IV-TR is entered into a reference list slightly differently:
American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (Revised 4th ed.). Washington, DC: Author