A. The production of psychological symptoms is apparently under the individual's voluntary control.
B. The symptoms produced are not explained by any other mental disorder (although they may be superimposed on one).
C. The individual's goal is apparently to assume the "patient" role and is not otherwise understandable in light of the individual's environmental circumstances (as is the case in Malingering).
Differential diagnosis of this disorder from other mental disorders is extremely difficult. The clinician may notice that the total clinical picture is not characteristic of any recognized mental disorder. Psychological tests (e.g., projective tests, or the Bender-Gestalt) may be helpful when the responses elicited suggest a mixture of perceptual, cognitive, and intellectual impairment that is not characteristic of any mental disorder but suggests, rather, the individual's concept of mental disorder. There is the danger, however, that simulated bizarre responses will be taken at face value.
A true Dementia frequently has a demonstrable organic etiology or pathophysiological process. In "pseudo"-dementia there are often near-miss, approximate answers rather than gross inability to answer questions correctly, as is often the case in a Factitious Disorder.
In a true psychosis, such as Brief Reactive Psychosis or Schizophreniform Disorder, the individual's behavior on the ward generally will not differ markedly from his or her behavior in the clinician's office. In contrast, in a Factitious Disorder with psychotic features the individual may appear to respond to auditory hallucinations only when under the impression that he or she is being watched.