Because of the substantial benefits available to individuals with a confirmed PTSD diagnosis, which causes occupational impairment, the distinct possibility of false diagnoses exist, some of which are due to malingering of PTSD. Malingering of PTSD consists of one feigning the disorder. Post-traumatic stress disorder (PTSD) is an anxiety disorder that may develop after an individual experiences a traumatic event. In the United States, the Social Security Administration and the Department of Veterans Affairs each offer disability compensation programs that provide benefits for qualified individuals with mental disorders, including PTSD. Malingering can lead to a decline in research and subsequent treatment for PTSD as it interferes with true studies. Insurance fraud may also come about through malingering, which hurts the economy.

Motivation
Individuals who malinger PTSD may have several motivations for doing so. First, financial incentives are common. For example, the Department of Veterans Affairs offers substantial annual financial compensation to U.S. veterans who can prove that they have PTSD related to their military service. This potential compensation can create an incentive for veterans to malinger PTSD. Furthermore, the U.S. Social Security Administration offers social security disability payments to individuals documenting a disorder such as PTSD that impedes their ability to work, which additionally provides an incentive to malinger PTSD. Additionally, the potential for workers compensation can motivate individuals reporting a traumatic event at their workplace to fabricate PTSD; and finally the potential for personal injury lawsuits can motivate someone to malinger PTSD and sue an individual for causing PTSD as a result of attack, accident or other stressor.

Some individuals are known to malinger PTSD to obtain inpatient hospital treatment. Persons charged in criminal law cases are motivated to malinger PTSD in order to offset criminal responsibility for the crime or mitigate the associated penalties. Some individuals are motivated to malinger PTSD (e.g., related to combat) in order to gain honor and recognition from others.

Prevalence 
The prevalence of malingering PTSD varies based on what one may be seeking. Differentiating between forensic and non-forensic evaluations, it has been found that malingering may be attempted in 15.7 percent of forensic evaluations and 7.4 percent of non-forensic evaluations. As mentioned above, personal injury lawsuits can motivate someone to malinger PTSD. It is thought that between 20 and 30 percent of these people seeking settlements have malingered their PTSD results. It is also believed that a minimum of 20 percent of veterans seeking combat compensation have malingered.

Cases within the criminal justice system also vary. A malingering rate between 8 percent and 17.4 percent was found in subjects in competency to stand trial assessments. Of incarcerated subjects seeking psychiatric services, a much higher range between 45 percent and 56 percent were suspected to malinger. Malingering cases were also positively correlated with severity of the crimes for subjects in competency to stand trial assessments. Malingering rates for murderers and robbers are greater than double the rest of subjects seeking incompetency.

Psychological assessment findings
The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) is a self-reported personality test which is the most widely used psychological assessment measure in research to detect malingered PTSD, typically by comparing genuine PTSD patients with individuals trained and instructed to fabricate PTSD on the MMPI-2. Numerous studies using the MMPI-2 have demonstrated a moderately accurate ability to detect simulated PTSD. Validity scales on the MMPI-2 that are reasonably accurate at detecting simulated PTSD include both the Fp scale developed by Paul Arbisi and Yosef Ben-Porath, and the Fptsd scale developed by Jon Elhai for combat survivors. These two scales have shown differing results. The Fp scale is the most helpful malingering predictor in civilian PTSD patients, whereas the Fptsd scale is a better predictor in combat PTSD patients.

Other psychological test instruments have been investigated for PTSD malingering detection ability, but have not approached the accuracy rates of the MMPI-2. These tests include the Personality Assessment Inventory and Trauma symptom inventory. The current literature modestly supports the effectiveness of the Personality Assessment Inventory or PAI at detecting malingering of post-traumatic stress disorder or PTSD.  Although results are mixed, the validity indicators of the PAI have been found to be effective at differentiating malingered PTSD from a diagnostically supported diagnosis of PTSD. Specifically, the negative impression management or NIM scale, the malingering index scale or MAL, and the negative distortion validity scale or NDS of the PAI are interpreted in detecting malingering of PTSD.

It is important to use multiple assessments when determining malingering of PTSD and not only rely on one test. A preliminary test which can be used is the Miller-Forensic Assessment of Symptoms (M-FAST). It can find 78 percent of test-takers asked to feign results and only takes between 5 and 10 minutes. Interviews hosted by clinicians are sometimes preferred over self-reported tests. These include the Clinician-Administered PTSD Scale (CAPS) or the Structured Interview of Reported Symptoms-2 (SIRS-2). Each of these include and interviewer who asks an interviewee a series of questions. The CAPS asks interviewees to rate items on a scale while the SIRS-2 may ask questions that could elicit a response that would expose malingering. The SIRS-2 has high accuracy in general malingering and PTSD malingering.

References

Anxiety disorders
Factitious disorders
Post-traumatic stress disorder