You can “malinger” — fake — virtually any mental disorder, because mental illness is defined by symptom lists that are self-reported. That is, you tell the doctor or therapist the symptoms you’re experiencing, and they simply go down the list and figure out which disorder the symptoms best fit into. Since the symptoms are self-reported, you can easily make up the symptoms to qualify for whatever diagnosis you want.
In medicine, things are a bit different. Although doctors might use your self-reported symptoms as a starting point on how to diagnose the medical problem you present with, they can usually followup by ordering a series of laboratory tests to confirm their diagnosis. There is no equivalent for mental health concerns (although there are many paper-and-pencil psychological tests have very good validity when it comes to differential diagnoses; these, however, are rarely used in daily practice).
So when I come across an article like this Associated Press one — talking about how some soldiers may be faking post-traumatic stress syndrome (PTSD) in order to gain benefits — it makes me cringe a little.
Last week, we noted along with many news outlets that a biomarker had been apparently discovered for PTSD. The researchers claimed they had a new tool to help make a differential diagnosis of posttraumatic stress disorder (PTSD).