Using the MMPI-2 to diagnose post-traumatic stress disorder

Personality Assessment Inventory Critique: MMPI-2 and Post Traumatic Stress Disorder

Post-Traumatic Stress Disorder (PTSD) is an anxiety order, which develops in response to exposure to a traumatic event. The event usually involves violence or the threat of violence. PTSD primarily affects adults, but can also affect children. Women seem more susceptible to PTSD than men, and it is not unusual for victims of sexual assaults or other violent attacks to develop some form of PTSD. However, the general public is probably most familiar with male victims of PTSD, because military personnel who have been in combat situations are a high-risk group for the disorder. Because it is an anxiety disorder, the symptoms of PTSD can manifest as physical problems, much like any other anxiety order. However, people with PTSD often manifest symptoms related to reliving the traumatic event, including but not limited to flashbacks. Because PTSD is an anxiety disorder, it can be difficult to differentiate between it and other anxiety disorders. Moreover, because a PTSD diagnosis can garner disability and other benefits, it is important to be able to differentiate PTSD from other anxiety disorders and to verify the diagnosis through objective testing. One of the way that mental health professionals help reach a PTSD diagnosis is to administer the Minnesota Multiphasic Personality Inventory, Second Version (MMPI-2) to patients presenting with symptoms consistent with PTSD.

Characteristics, uses, and purposes of the MMPI-2

The MMPI-2 is a written, self-report style measurement tool which is used to assess people for psychological disorders and to assess cognitive functioning. The test asks the subject a variety of questions, which are geared toward examining the subject's cognitive and emotional skills and traits. The test has validity scales included in it, to help prevent faked results. Furthermore, there are ten personality scores scaled in the test, which evaluate specific personality traits. When administered by a trained clinical professional in conjunction with other assessment tools, the MMPI-2 has been deemed successful in aiding in the diagnosis of certain mental disorders.

The MMPI-2 is the most widely used assessment tool in clinical psychology. This is largely due to the reliability and validity of its assessments. There are four different validity scales in the MMPI-2: the Cannot Say Scale, the Infrequency Scale, the Lie Scale, and the Defensiveness Scale (Trull, 2005). Each of these scales picks up on different factors that can impact the validity of any test results. For example, the Cannot Say Scale measures the number of unanswered items. The Infrequency Scale measures deviant responses, which can indicate a tendency towards symptom exaggeration. The Lie Scale is a set of questions geared towards detecting when someone is trying to make himself seem better adjusted than he actually is.

This is different from the Defensiveness Scale, which relates to people's willingness to admit problems to themselves vs. An intentional lie to make themselves seem better adjusted. (Trull, 2005).

Analysis

One of the difficulties in the diagnosis and treatment of people with PTSD is the fact that many of them are considered symptom overreporters, which could impact their diagnoses and treatment plans. In a study focusing on symptom overreporters among veterans with PTSD, Kashdan et. al investigated how individual differences in presentation style can impact how mental health professional assess and treat veterans returning from combat (2007). To do so, they recognize that PTSD diagnoses can be a controversial area, given that some veterans may be intentionally or unintentionally misrepresenting their symptoms.

Therefore, they investigated "whether diminished positive affect and emotional expression provide unique insight into the concept of symptom overreporting" (Kashdan et. al, 2007). What they discovered was that, "controlling for shared variance between PTSD and depressive symptoms, anhedonia was the only symptom to adequately differentiate symptom overreporters from non-overreporting veterans" (Kashdan et. al, 2007). However, the reality is that anhedonia reports would be expected to be greater in overreporters, because it would align with Veteran Administration disability guidelines. Therefore, the team went further and investigated whether overreporters also reported positive emotions at a higher level than non-overreporters, which they did. These findings could have supported the idea that symptom overreporters were malingerers, and instead show that these subjects may be responding truthfully in regards to psychological functioning. However, the findings were also very suggestive of the idea that symptom overreporters had some knowledge of how to respond to the MMPI-2 to get a disability diagnosis (Kashdan et. al, 2007). Therefore, before making a diagnosis of PTSD for disability purposes, the diagnosing clinicians may need to investigate whether the clients have knowledge of PTSD, the disability system, and any current claims seeking disability (Kashdan et. al, 2007). This is not to suggest that all overreporters are seeking compensation, but simply to acknowledge the reality that, in veterans, the existence of financial incentives to overreport makes diagnosis more difficult.

Because of there are real incentives for people, especially veterans, to overreport PTSD symptoms, it is important to understand whether the MMPI-2 is able to screen out those faking or exaggerating their symptoms. Greiffenstein et. al compared the MMPI-2's F-family scales to the Lees-Haley Fake Bad Scale in order to determine whether the MMPI-2 was able to accurately predict improbably psychological trauma claims in applied setting. (2004). What they discovered was that, while the FBS showed positive predictive power, the F-family did not. They theorized that this was due to the use of psychotic simulation to develop the F-family scales, while the FBS had been created using people actually suffering from PTSD (Greiffenstein et. al, 2004). As a result, they concluded that the FBS the more appropriate tool to use if clients were seeking compensation for PTSD (Greiffenstein et. al, 2004). However, there are problems with the use of the FBS, because many clinicians believe that it is overly exclusive.

Of course, the MMPI-2 does not rely solely upon the F-family to determine the veracity of PTSD diagnosis and findings. Instead, the MMPI-2 utilizes an Infrequency Posttraumatic Stress Disorder Scale (Fptsd) to specifically determine the validity of PTSD claims. To do this, Marshall and Bagby instructed research participants to feign PTSD and compared those results to disability claimants with PTSD (2006).

What they found was that those subjects who were instructed to feign PTSD scored higher on the F. scales and the Fptsd scale compared to their normal responses, and compared to those people having PTSD. However, they also found that the Fptsd scale was not better able to determine false reports than the other F-scales, suggesting that the Fptsd scale does not increase the validity of the MMPI-2 for the diagnosis of PTSD (Marshall and Bagby, 2006).

Identification of psychometric properties

The MMPI-2 measures a wide variety of psychometric properties, many of which one would expect to be impacted by a PTSD diagnosis. There are ten scales measuring different properties including: hypochondriasis, depression, hysteria, psychopathic deviance, masculinity-femininity, paranoia, psychasthenia, schizophrenia, hypomania, and social introversion. Because PTSD is classified as an anxiety disorder, the measures for paranoia, psychasthenia, and schizophrenia are especially relevant. However, given that many PTSD patients are also severely depressed, that scale is important as well. In fact, it is important to understand that the MMPI-2 must be administered as a whole and that one cannot consider scores on any one area of the test in isolation from a subject's other results.

Moreover, it is important to recognize that while the scales may carry official names, they do not only measure the suggested disease. For example, the schizophrenia scale appears to measure the degree of alienation that a subject feels from society at large, a number that is going to vary depending on one's role in society. For example, one would expect a healthy minority member to have a higher score of on the schizophrenia scale because minorities are generally more disenfranchised from society at large. Therefore, the tool cannot be properly utilized if the testing clinician is lacking basic facts about the subject being tested.

Moreover, these scales test for a variety of different disorders. Because PTSD is a complex disease, it often co-presents with other disorders, like addiction and depression.

Conclusion

The MMPI-2 is a very complex test that sets out to evaluate whether patients fit into certain mental health categories. The test has good utility in some areas, and can certainly suggest an array of appropriate diagnosis and treatment options to a qualified clinician administering the test. However, because many people have financial or other incentives to try to fake a PTSD diagnosis, it should be used with caution in that arena. While individual characteristics are always important in MMPI-2 diagnoses, a clinician may have a responsibility to probe and even investigate an individual's familiarity with the test and its qualifications before making a PTSD diagnosis using the MMPI-2 as the diagnostic tool. Furthermore, because PTSD evaluations are so frequently linked to disability determinations, the clinician has a heightened responsibility to ensure that a patient is being directed to appropriate care.