The Use Symptom Validity Testing And Structured Inventory Of Malingered Symptomatology Techniques In Identifying Malingering
Introduction
The belief that defendants in court are always honest has long been repudiated. People who stand to gain something by being dishonest might be especially motivated to feign or exaggerate symptoms of physical or psychological disorders. Successful feigning of symptoms could lead to a myriad of benefits provided by the state or the court of law. This fabrication or magnification of symptoms is referred to as malingering. There are a number of records showing that people are successful at feigning disabilities over long periods of time. A well-known case of malingering is that of Alan Knight, a man who feigned quadriplegia for over two years to avoid prosecution for conning an elderly lady out of her life savings. He was eventually apprehended because he was caught on CCTV while pushing a trolley around a shop. Rosenhan’s (1973) classical study is another example where malingering went undetected. Eight pseudo-patients feigned hearing voices and were granted admission to several psychiatric hospitals. Although their symptoms disappeared immediately after admission, they were diagnosed with schizophrenia and none of the pseudo-patients were thought to be malingering.
These cases indicate that people are not highly skilled at detecting fabricated symptoms. Therefore, scientists have come up with tests that could facilitate detection of these malingerers. The present study will focus on two of these tests, namely, Symptom Validity Testing (SVT) and the Structured Inventory of Malingered Symptomatology (SIMS). These tests have both been shown to have moderate to high sensitivity and specificity. The SVT is a tool that was originally designed to detect feigned symptoms of deafness and memory dysfunctions. More recently, it has been used in cases of dubious memory loss to detect possible symptoms of malingering. The SVT is a binomial, forced-choice test that questions respondents about the details of a crime they allegedly committed. The questions are uniquely tailored to every case and the answer options must be made equally plausible for an unbiased responder. An individual suffering from genuine amnesia would score randomly on this test (i.e., approximately equal distribution of correct and incorrect answers). A person who scores significantly below chance (i.e., choosing the incorrect answer a significant number of times over the correct answer) is seen as strategically trying to avoid the correct answer option and therefore, feigning their memory loss. A person who scores significantly above chance cannot be shown to be feigning and is simply giving a truthful account (i.e., correctly answering a significant portion of the questions). Earlier studies on the value of the SVT commented that the test was limited because of its transparency . Therefore, a number of bogus questions (i.e., questions that have no correct answer as they pertain to details that even the perpetrator could not have known) were included to make the rationale behind the test less translucent. The SIMS is a self-report measure that tests for feigned or exaggerated symptoms of psychiatric disorders and cognitive dysfunctions. The SIMS counts 75 questions referring to malingering on five different subscales i.e., affective disorders (AF), amnestic disorders (AM), low intelligence (LI), neurological impairment (NI), and psychosis (P). The SIMS mainly includes atypical and bizarre symptoms. The test builds on the idea that individuals who feign or fabricate symptoms do not know how persons actually suffering from these disorders act and would therefore be more likely to endorse these atypical symptoms.
This study used a cut-off score of 14. Scores above 14 could be indicative of feigned behavior. The cut-off scores for the different subscales (i.e., AF (>5), AM (>2), LI (>2), NI (>2), P (>1)) were taken from Parks, Gfeller, Emmert, and Lammert (2017) .The present case study aimed to assess the applicability of the SVT and the SIMS on a very limited sample. A first objective was testing whether a person with perpetrator knowledge could pass the SVT and SIMS while feigning amnesia. A second objective was to uncover whether a participant with layman’s knowledge about low intelligence could pass the SIMS while feigning symptoms hereof.
Method
Participants
Two participants were recruited for the study, one male, one female. One participant completed the SVT and the SIMS. The other participant only filled out the SIMS questionnaire. The participants were 19 and 48 years of age. Participants were either currently enrolled at a university in Belgium or had previously received their master’s degree there. Neither were clinically diagnosed with any of the disorders tested in the SIMS.
Symptom Validity Testing
The participant completing the SVT read a report pertaining to a child sexual abuse case. The report included excerpts of conversations between the boy and his mother, interviews between the boy’s mother and the police and interviews between the offender (i.e., a chaplain) and the police. These conversations and interviews included details about the crime and the crime scene. The report also contained an extract where the chaplain gave a statement about his alleged where about on the evening of the crime. The participant was instructed to identify himself with the offender (i.e., the chaplain accused of sexually abusing a choir boy) and to imagine having committed the offence. He was furthermore instructed to pretend to have amnesia for this crime and to answer the questions posed in the SVT as such. After completion of the questionnaire, the participant was informed of the correct answer options. The participant received the same report as the one that was used by the researchers to construct the SVT items. The SVT completed by the participant consisted of 10 critical questions picked from a larger pool of 15 questions by using the Doob and Kirshenbaum (1973) piloting procedure. During the pilot, the 15 critical items were handed to 12 individuals blind to the crime scenario who were asked to choose the most plausible alternative. Mean binomial probabilities were then calculated and items that had probabilities of the correct answer being picked below .3 or above .7 were removed from the questionnaire. Five items had to be removed leaving a total of 10 unbiased critical items referring to the crime and the crime scene. These critical items were randomly alternated with seven bogus items also included in the questionnaire. The unbiased questionnaire can be found in the appendix, with the correct responses indicated by an asterisk (*).Structured Inventory of Malingered Symptomatology The participant who previously completed the SVT was asked to maintain his role as the chaplain who claimed amnesia to fill in the SIMS. The second participant, who only filled out the SIMS, was instructed to feign low intelligence. Both participants filled out the entire questionnaire, consisting of 75 questions. Scores could range from zero to 75 and as previously mentioned, a cut-off score of 14 was used for the total SIMS score.
Results
Symptom Validity Testing
The participant’s z-score was calculated using the formula stated in Denney (1996).Z=(((X±.5)-N*P))/( Ö(N*P(1-P)))Where Z is the test statistic, X is the number of correct responses, N the total number of questions, and P the probability of a correct answer given a truly naïve respondent (here 0.5). The result was not significant (total SVT = 5, z = -1.45, p =.74, one-tailed). These results show that the participant had a total SVT score in the random range.
Structured Inventory of Malingered Symptomatology
The two total scores for the participants are shown in Figure 1. The participant who feigned amnesia and completed both tests had a score of 5 on the SIMS and thus, did not exceed the cut-off score of 14. This participant’s scores of the individual subscales (AF = 3, AM = 2, LI = 0, NI = 0, P = 0) never exceeded the different cut-offs. The participant who feigned low intelligence and only completed the SIMS did exceed this cut-off with a score of 35. Moreover, she surpassed the cut-off scores for all the individual subscales (AF = 10, AM = 4, LI = 9, NI = 7, P = 5).
Discussion
The SVT and the SIMS have previously been used in research to facilitate the detection of malingering. The current study tested the applicability of these tests in a very limited sample. The participant who received perpetrator knowledge about a sexual abuse case and was asked to feign amnesia completed both tests. The p-value on his SVT test did not reach significance, which means that no assertion could be made about the veracity of his statements. This participant’s SIMS scores, both the total score and the scores on the individual subscales, showed the same pattern. He once more, did not exceed the cut-off points that would indicate symptoms of malingering with reasonable certainty. The participant who feigned amnesia and solely completed the SIMS showed a different response pattern. Her scores on the test did surpass this cut-off score. She surpassed the scores on all five subscales, as well as the total score. These scores would lead us to, rightfully, conclude she was malingering. Hence, the current results do not offer a conclusive answer as to how applicable these tests are in a small sample. While the individual subscales of the SIMS were mentioned in the present research, the sensitivity and specificity of these scales has been heavily debated and often concluded to be poor indicators of malingering. Other studies have furthermore, shown that there is considerable difference in the effectiveness of the different subscales in detecting feigned symptoms. We therefore, caution the use of these scales in drawing conclusions about a person’s veracity. Another point of importance is that the cut-off score of 14 on the SVT should not be utilized for absolute assessment of feigned symptoms. This cut-off can only be justified as part of a screening procedure, where surpassing the cut-off indicates further testing is necessary. Hence, passing this test does not indicate with absolute certainty that that a person was not malingering, just like failing the test should never be used as the sole determinant to state a person was malingering.
There are a few limitations that should be made apparent in the present study. Firstly, the number of critical items in the SVT was highly limited. Research has shown that increasing the number of items in the SVT could enhance its sensitivity. Secondly, the participant that completed both tests indicated he had some idea of the rationale behind the tests. His suspicion might have helped him in answering the questions in such a manner that concealed his feigning.
Lastly, while no stark conclusions can be drawn from the limited sample used in the present study, it should, however, be pointed out that real life cases oftentimes have only a single perpetrator. The current results for the effectiveness of indicating feigned symptoms in both tests is not highly promising. The researcher, therefore, advocates for additional testing on both the SVT and the SIMS.
