The PMHNP is evaluating a 27-year-old woman who has been diagnosed with posttraumatic stress disorder due to a childhood history of sexual trauma. Today she has brought her husband with her. He reports that he sometimes feels he has "two wives who have different likes and dislikes, different tastes in food, clothing, and entertainment, and even talk in different voices." The patient says she has periods in which she has no memory of what took place. As an example, she says she may be dining out with her husband and have no recollection of how she got there. The PMHNP will evaluate for which of the following disorders?