Forensic assessments must evaluate systematically the accuracy and forthrightness of individuals referred for evaluation of psycholegal issues. Among different response styles that should be considered, malingering is a cornerstone issue for forensic consultations. Malingering is defined by the Diagnostic and Statistical Manual of Mental Disorders (fourth edition; DSM-IV) of the American Psychiatric Association as a deliberate fabrication or gross exaggeration of symptoms for an external goal. Feigned symptoms and associated features may be psychological, medical, or a combination of both. Forensic psychologists and psychiatrists should note that minor or even substantive exaggerations do not warrant the classification of malingering; only grossly exaggerated symptoms qualify for malingering. An example of gross exaggeration would be the deliberate misrepresentation of an occasional thought about one’s demise (e.g., “I wish I was dead”) as a current suicidal ideation that includes planning and possible preparation. Because court reports require precision, forensic psychologists may wish to operationalize “gross exaggeration.” For such purposes, the Schedule of Affective Disorders and Schizophrenia (SADS) provides a criterion-based standard for rating the severity of reported symptoms. Many symptoms on the SADS are rated on six levels of severity: 1 = absent, 2 = slight or subclinical, 3 = mild, 4 = moderate, 5 = severe, and 6 = extreme. According to Richard Rogers, gross exaggeration should be defined as a minimum of three levels of amplification. To qualify as grossly exaggerated, (a) slight symptoms would need to be severe or extreme and (b) mild symptoms would need to be extreme.
Malingering is a DSM-IV classification and not a formal diagnosis. This distinction is critical to forensic evaluations. Malingering is categorized as a “V code,” which signifies an undiagnosed condition that may be the focus of clinical attention. Note that the operative word is “may,” suggesting that malingering is not always a focal point for clinical attention. More important, V codes do not provide inclusion criteria for clearly establishing a clinical condition. The screening indicators provided in DSM-IV are merely meant to raise suspicions of malingering. Misuse of these screening indicators as inclusion criteria is a very serious breach of professional practice with ethical implications. To underscore this crucial issue, forensic clinicians should draw no conclusions, however tentative, regarding the presence or absence of malingering on the basis of DSM-IV screening indicators.
A careful analysis of DSM-IV screening indicators suggests that they should not be used for any purpose, because of their inaccuracies and lack of discriminability. Based on available research, DSM-IV screening indicators are likely to lead to false positives approximately 80% of the time. Consider for the moment the perils of applying these indicators to criminal-forensic cases. Two of the four indicators (e.g., forensic context and antisocial personality) occur in a high proportion of cases, rendering them ineffective at distinguishing malingering from genuine disorders. The remaining two indicators (lack of cooperation and marked discrepancies) also lack discriminability.
Domains of Malingering
Malingering is almost never a pervasive response style. Instead, malingerers are typically selective about what types of symptoms are feigned and what specific goals can be achieved. Three general domains of malingering have been identified: mental disorders, cognitive abilities, and medical complaints. Each domain places specific demands of malingerers, who are attempting a successful performance (i.e., the avoidance of detection). In the next three paragraphs, each domain is explored.
Feigned Mental Disorders. Malingerers in this domain must create a plausible set of symptoms with a credible description of their onset and course. Importantly, they must decide how much insight to have regarding these symptoms and their effects on daily functioning. For truly sophisticated presentations, feigning must take into account negative symptoms (e.g., the absence of spontaneous speech) as well as positive symptoms (e.g., the presence of auditory hallucinations). If provided treatment, they must decide what changes, if any, occur with their symptoms and their insights into these symptoms.
Feigned Cognitive Impairment. Malingerers in this domain must exhibit “effortful failures.” In other words, they must portray seemingly genuine effort while making plausible mistakes on neuropsychological and intelligence testing. While the immediate task of feigning appears comparatively easy (i.e., “try hard but get it wrong”), malingerers face an additional hurdle of feigning believable deficits in light of past documentation. In most instances, for example, the feigning of mental retardation poses a daunting challenge because academic records (e.g., school performance and aptitude tests) provide relevant data about intellectual abilities.
Feigned Medical Complaints. Malingerers in this domain can be categorized as feigning either nonspecific complaints or a specific diagnosis. Nonspecific complaints (e.g., headaches, fatigue, and pain) are relatively easy to generate and difficult to disprove, especially when described as intermittent or sporadic. However, malingerers must decide whether such complaints will be sufficient to meet their goals (e.g., unwarranted compensation in a personal injury case). Far more complex is the feigning of specific medical disorders that may involve the deliberate contamination of laboratory tests. Health care staff may be alerted to malingering by anomalies in test results. In addition, malingerers may evidence an unlikely level of sophistication in their knowledge of test findings that is uncharacteristic of genuine patients.
Different detection strategies are required for each domain. For example, assessment methods for identifying bogus hallucinations are likely to be ineffective with individuals claiming memory loss secondary to a traumatic injury. In this instance, persons with purported amnesia have no reasons to fabricate psychotic symptoms. In the next section, detection strategies for feigned mental disorders and feigned cognitive impairment will be addressed. The third domain, feigned medical complaints, is beyond the scope of this contribution.
Malingering Detection Strategies
In the assessment of malingering, a crucial distinction must be made between common and discriminating characteristics. As part of the external motivation, many malingerers are involved in forensic evaluations. However, this is a common but not discriminating characteristic that is unhelpful in the evaluation of potential malingering. Naive practitioners have mistakenly assumed that the obverse is true: “If the majority of malingerers are involved in forensic referrals, then the majority of forensic referrals are malingerers.” This logic is fundamentally flawed and can lead to tragic errors. To illustrate this logical fallacy, consider the proposition “Most murderers are men; therefore, most men are murderers.” However, its persistence among naive practitioners may stem in part from their fundamental misunderstanding of the DSM-IV screening indicators.
Discriminating characteristics of malingering require that specific variables differentiate between genuine and feigned protocols. For example, individuals with genuine memory problems will conform to certain learning principles (e.g., recognition is easier than recall), whereas some malingerers will fail equally on recognition and recall tasks. Therefore, the violation of a learning principle is a discriminating characteristic and has the potential to be useful in the evaluation of feigned cognitive impairment. Discriminating characteristics form the bases for detection strategies.
What is a detection strategy for malingering? According to Richard Rogers, detection strategies represent a standardized method for differentiating between malingered and genuine conditions. Detection strategies must be conceptually based and empirically validated. For instance, the violation of a learning principle has a sound conceptual basis. For empirical validation, detection strategies should not only produce substantial effect sizes (i.e., large group differences) but also facilitate via utility estimates in the individual classification of malingered versus genuinely impaired cases.
Detection Strategies for Feigned Mental Disorders
Persons with malingering mental disorders are often unaware of characteristic patterns commonly found with bona fide patients. As a result, they often have unlikely presentations, characterized by atypical symptoms and symptom patterns, not usually found in genuine populations. In addition, malingerers often miscalculate the typical intensity of common symptoms and associated features. Therefore, detection strategies can also capitalize on amplified presentations, for which the symptoms may appear genuine, but the reported frequency and intensity is highly uncharacteristic of genuine populations. Outlined below are detection strategies based on unlikely and amplified presentations.
Unlikely Presentations
Rare Symptoms. Malingerers are unlikely to recognize which symptoms occur very infrequently among genuine patients. Reporting a large number of rare symptoms is strongly indicative of feigning.
Symptom Combinations. Malingerers are likely to recognize common psychological symptoms that are experienced by genuine patients. They are unlikely, however, to recognize that some psychological symptoms do not typically occur together. Reporting a large number of uncommon symptom combinations is indicative of feigning.
Improbable Symptoms. Improbable symptoms are extreme and fantastic in quality. These symptoms can be thought of as extreme variants of rare symptoms due to their preposterous and seemingly ridiculous content. Frequent report of improbable symptoms indicates feigning.
Unlikely Patterns of Psychopathology. This strategy relies on the idea that there are general patterns of psychopathology that are unlikely to be experienced by psychiatric patients. As the symptom combination strategy relies on unlikely patterns at a symptom level, the unlikely patterns of psychopathology strategy relies on more collective and complex patterns that are improbable in genuine populations. Owing to the complexity of this strategy, it has been primarily employed on multiscale inventories.
Amplified Presentations
Indiscriminate Symptom Endorsement. This strategy relies on the finding that malingerers will report a large array of psychological symptoms, larger than that of even the most impaired clinical patients. Endorsement of a very large number of symptoms may indicate feigning.
Symptom Severity. This strategy relies on the finding that malingerers will report a large number of symptoms as extreme or unbearable. This strategy should not be confused with indiscriminate symptom endorsement. Symptom severity relies on the amplified “depth” of symptoms as opposed to the atypical “breadth” assessed by indiscriminant symptom endorsement.
Obvious Symptoms. This strategy relies on the endorsement of very blatant symptoms of mental illness by malingerers. Obvious symptoms are different from rare symptoms due to the typicality of obvious symptom content. These symptoms are not defined by their rarity in clinical populations but by their obvious relationship with severe psychological disorders. Comparison between an individual’s report of obvious versus more subtle symptoms has also been useful in the detection of feigning. Endorsement of a large number of obvious symptoms may be indicative of feigning.
Erroneous Stereotypes. The erroneous stereotype strategy relies on common misperceptions about psychological symptom experiences. These symptoms describe lay nonprofessional general perceptions about persons with mental disorders. Individuals who agree with many of these erroneous stereotypes are likely to be feigning.
Reported Versus Observed Symptoms. This strategy relies on the observation of individuals’ clinical presentation and their report of psychological symptoms. Reporting of symptoms that are more impaired than what is observed may be an indication of feigning. The reported versus observed strategy is not a simple comparison of consistency. Only reports of symptoms that are “worse” than observed should be considered as possible feigning.
Many psychological measures possess scales designed to assess a patient’s likelihood of feigning mental disorders. Currently, the Minnesota Multiphasic Personality Inventory–2 (MMPI–2) and Structured Interview of Reported Symptoms (SIRS) are the most widely used tests for the detection of feigned mental disorders. The MMPI–2 possesses an impressive research base demonstrating its support for the detection of feigning. The SIRS has been considered by many to be the gold standard psychological test for the detection of feigned mental disorders. Both measures contain multiple scales that employ a variety of different detection strategies. For both the MMPI–2 and the SIRS, research has demonstrated large to very large effect sizes that demonstrate marked differences between genuinely disordered and feigned groups. The basic distinction between the two measures involves individual classification via utility analysis. The MMPI–2 is generally ineffective at individual classifications because (a) cut scores range widely and (b) substantial overlaps on validity scales between genuine and feigned protocols reduce accuracy. In contrast, the SIRS has established effective cut scores that minimize false positives and overall errors. Thus, the SIRS provides accurate clinical data for individual classifications.
Detection Strategies for Feigned Cognitive Disorders
The assessment of feigned cognitive impairment has largely been limited to evaluations of memory impairment and general intellectual functioning. Detection strategies for feigned cognitive impairment have generally relied on excessive impairment, which is based on either unexpectedly poor performance on cognitive tasks or unexpected patterns that are characterized by unlikely endorsement patterns of items assessing cognitive abilities.
The following are detection strategies based on excessive impairment and unexpected patterns.
Excessive Impairment
Floor Effect. This strategy relies on the failure of malingerers to answer accurately very simple test items. Even the most cognitively impaired individuals are able to answer floor-effect items correctly. Individuals who fail to endorse floor-effect items are likely to be indicative of feigning.
Symptom Validity Testing. This strategy relies on the probability that a genuine person without any ability would obtain a proportion of correct responses, based on chance alone, when presented with a multiplechoice format. Performance markedly below this chance level is strong evidence of purposeful failure (i.e., malingering). For this strategy to be effective, each alternative must have a similar likelihood of being chosen.
Forced Choice Testing. This strategy relies on the accurate establishment of normative data for cognitively impaired individuals. Individuals who perform far worse than the normative data on a multiple-choice test of cognitive abilities are suspected to be feigning. This strategy is vulnerable to errors because normative data do not take into account multiple cognitive conditions and complications by mental disorders and ineffective coping.
Unexpected Patterns
Magnitude of Error. This strategy relies on the identification of patterns of failure on cognitive tasks that are atypically incorrect. As the name denotes, it is the magnitude of incorrect endorsements, not simply the presence of an incorrect response, that indicates feigning based on this strategy. The magnitude of error specifically relies on a malingerer’s tendency to report blatantly incorrect answers as opposed to “plausibly” incorrect answers.
Performance Curve. This strategy compares performance on easier tasks with performance on more difficult tasks. If individuals perform worse on easy tasks than on difficult tasks, feigning impairment can be suspected. This strategy can be very effective, especially with measures that represent (a) a wide range of item difficulty and (b) the absence of an obvious progression from simple to difficult items.
Violation of Learning Principles (VLP). This strategy relies on established learning principles to identify atypical performance of feigners that is incompatible with our knowledge of learning. When a person does not conform to the expected pattern of results based on a learning principle, he or she is suspected to be feigning cognitive deficits. As a good example, impaired individuals are consistently more successful at recognition than recall because the latter places a greater demand on memory abilities. When recall equals or even surpasses recognition, an important learning principle has been violated. This violation is indicative of feigned cognitive impairment.
Dozens of measures for feigned cognitive impairment have been developed in the past decade. Many measures are based on a single detection strategy (e.g., floor effect) and are vulnerable to coaching (e.g., put forth a good effort). Forensic practitioners should look for well-validated measures that have been tested with multiple groups representing different cognitive conditions. An example is the Test of Malingered Memory. In addition, practitioners may wish to include a measure that relies on symptom validity testing, such as the Portland Digit Recognition Test. Although such measures identify only a minority of malingerers, they are accurate in these classifications with very small false-positive rates.
Conclusion
Malingering is a superordinate issue in forensic evaluations. Conclusions about malingering are likely to trump all other diagnostic and forensic considerations. Because of its importance, forensic clinicians must take special care to ensure the accuracy of their determinations. Whenever feasible, these determinations should use multiple detection strategies and several validated malingering measures. Further corroboration should be sought via clinical interviews and collateral sources (e.g., informant interviews and mental health records). Finally, the classification of malingering does not truncate the assessment process. Many malingerers also have genuine disorders that may be relevant to the forensic referral.
References:
- Reynolds, C. R. (Ed.). (1998). Detection of malingering during head injury litigation. New York: Plenum.
- Rogers, R. (Ed.). (1997). Clinical assessment of malingering and deception (2nd ed.). New York: Guilford Press.
- Rogers, R. (Ed.). (in press). Clinical assessment of malingering and deception (3rd ed.). New York: Guilford Press.
- Rogers, R., & Bender, S. D. (2003). Evaluation of malingering and deception. In A. M. Goldstein (Ed.), Handbook of psychology: Vol. 11. Forensic psychology (pp. 109–129). New York: Wiley.
- Rogers, R., & Shuman, D. W. (2005). Fundamentals of forensic practice: Mental health and criminal law. New York: Springer.