Dissociative Amnesia? It Might be Organic Memory Loss!

This article discusses the possibility of practitioners who mistake organic memory loss for dissociative amnesia. It starts with the case of a young man with complete retrograde amnesia due to a traumatic head injury. Because he did not show any gross neurological abnormalities, a neurologist thought his amnesia had a psychological origin. An extensive neuropsychological examination revealed that the man did have an organic reason for his amnesia. Next, the existence of dissociative memory loss as well as isolated organic retrograde amnesia is considered. While cases of organic memory loss are well-documented, there is hardly any evidence for dissociative amnesia. It is argued that organic memory loss might be mistakenly taken for dissociative amnesia. In line with the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, practitioners are advised to rule out the possibility of organic memory loss, before diagnosing a patient with dissociative amnesia.

The application of CT for 3D visualization of concealed bodies.

In forensic radiology, computed tomography (CT) is often used as a medical imaging technique to identify the cause and manner of death of deceased victims of a possible crime. In this study, medical imaging is used to examine concealed bodies and packaging materials. Medical imaging techniques, mainly CT scan, were used to scan packaged or concealed bodies inside containers to identify clues and evidence indicating whether a crime might have been committed. Also, scene integrity and scene safety along with a systematic search for relevant evidentiary items value were considered. Eighteen concealed bodies that had been assessed using medical imaging techniques between 2010 and 2018 at the request of the Dutch National Police were selected. The file records of each case contained imaging data, a photographic record of the unpacking procedure, a list of all items and traces found in the package, and the forensic pathology report. The images were assessed with respect to the different aspects of the case and through a systematic approach. The packages included adult males, adult females, newborn infants, and animals. All human cases were related to criminal offences. In nine adult cases, evidence of a possible violent death could be determined using CT imaging. The cause of death in newborn infants, however, could not be determined. In cases of dismemberment, the completeness of the body could be determined by CT imaging, and the cutting surfaces of bones could be matched on CT images. Regarding scene safety and integrity, in this study all relevant macroscopic items were detected on the CT images. The CT-scans were supplemented with fiduciary markers to better map CT data with the real objects. This information in combination with 2D and 3D images provided the forensic investigator with information on how to unwrap the package layer by layer and help determine different types of packaging materials. Different textiles could not always be identified. The orientation of the body within the packages was provided in all cases, and advice could be given on the optimal approach to access the contents. The overall detection rate of items was 78%. This is one of the first studies to illustrate the contribution of medical imaging, specifically CT scan, to the analysis of concealed bodies and packaging materials prior to unpacking. This demonstrates its contribution to a systematic approach of the investigation by ensuring the safety and health of the investigator while documenting and maintaining the integrity of the crime scene. Imaging also provides information that can be helpful to determine whether a crime might have been committed and reducing the risk of damaging a concealed body. Medical imaging also provides the forensic investigator with information to draw up a workplan prior to unpacking, minimising loss of evidence and determining whether different forensic specialists (e.g., digital or DNA) are needed. It is therefore strongly recommended to use medical imaging, especially CT scanning, before opening a package containing a concealed body.

Believing in dissociative amnesia relates to claiming it: a survey of people's experiences and beliefs about dissociative amnesia.

Dissociative amnesia is one of the most controversial categories in the field of psychiatry and clinical psychology. Self-reports of dissociative amnesia in the general population, and beliefs about this topic, have so far not been subjected to empirical scrutiny. Here, we surveyed a sample from the general population (N = 1017), revealing that about a tenth (n = 102) claimed to have experienced dissociative amnesia. Some claims pertained to amnesia for traumatic autobiographical experiences (e.g., sexual assault), while other claims reflected memory loss for experiences that can be regarded as non-traumatic or non-stressful (e.g., dissociative amnesia for an anniversary). Importantly, many participants believed in the existence of dissociative amnesia, and those who claimed dissociative amnesia indicated even more belief in this phenomenon than the rest of the sample. Finally, many participants indicated to have at least once claimed to have feigned memory loss in their life, and that they experienced some form of forgetting when trying to retrieve events for which they lied upon. Overall, our findings suggest that claiming dissociative amnesia goes hand in hand with believing in dissociative amnesia.

Retrieval-Induced Forgetting in the Feigning Amnesia for a Crime Paradigm.

Previous studies demonstrated that, when asked to honestly provide information about a mock crime, former feigners performed worse than those who were requested to confess to this event. Thus, feigning amnesia for a mock crime undermined genuine memory for the same experience. In the present study, we examined whether retrieval-induced forgetting (RIF) underlies this memory-undermining effect. After watching a mock crime, participants had to feign amnesia or confess to having committed that crime. Feigners were given retrieval practice instructions (i.e., retrieval-practice group) or no further instructions (i.e., control group). Immediately and 1 day later, all participants had to genuinely report what they remembered about the crime. Although simulators in the retrieval-practice group recalled the largest amount of information as a positive consequence of retrieval, the ratio for crucial crime-related details was lower than that exhibited by both simulators who were given no instructions and confessors. These findings suggest that RIF might play a role in forgetting critical information in claims of crime-related amnesia. Theoretical and practical implications will be discussed.

Feigning Hand Preference? A Case Report Preliminary Data.

Hand preference may be crucial in the forensic domain, notably in cases where the assailant is known to be left-handed and the defendant claims to be right-handed (or vice versa). In such cases, forensic psychologists or physicians may be asked to test the hand preference of the defendant. However, hand preference may be faked. The case described here illustrates this problem and addresses potential solutions. We also present preliminary data showing that a standard instrument for measuring handedness is sensitive to feigning. We conclude that when hand preference is determined, multiple sources of information should be assessed in order to identify possible feigning.

Testing Claims of Crime-Related Amnesia.

Many violent offenders report amnesia for their crime. Although this type of memory loss is possible, there are reasons to assume that many claims of crime-related amnesia are feigned. This article describes ways to evaluate the genuineness of crime-related amnesia. A recent case is described in which several of these strategies yielded evidence for feigned crime-related amnesia.

The Modified Stroop Task Is Susceptible to Feigning: Stroop Performance and Symptom Over-endorsement in Feigned Test Anxiety.

Some researchers argue that the modified Stroop task (MST) can be employed to rule out feigning. According to these authors, modified Stroop interference effects are beyond conscious control and therefore indicative of genuine psychopathology. We examined this assumption using a within-subject design. In the first session, students (N = 22) responded honestly, while in the second session they were asked to read a vignette about test anxiety and then fake this condition. During both sessions, we administered an MST consisting of neutral, anxiety-related, and test anxiety-related words. Participants also completed the Self-Report Symptom Inventory (SRSI; Merten et al., 2016) that focuses on over-reporting of pseudosymptoms. Our feigning instructions were successful in that students succeeded in generating the typical MST effect by providing longer response latencies on anxiety related (r = 0.43) and test anxiety-related (r = 0.31) words, compared with neutral words. Furthermore, students endorsed significantly more pseudosymptoms on the SRSI (r = 0.62) in the feigning session than in the honest control condition. We conclude that the MST effect is not immune to feigning tendencies, while the SRSI provides promising results that require future research.

Feigning Amnesia Moderately Impairs Memory for a Mock Crime Video.

Previous studies showed that feigning amnesia for a crime impairs actual memory for the target event. Lack of rehearsal has been proposed as an explanation for this memory-undermining effect of feigning. The aim of the present study was to replicate and extend previous research adopting a mock crime video instead of a narrative story. We showed participants a video of a violent crime. Next, they were requested to imagine that they had committed this offense and to either feign amnesia or confess the crime. A third condition was included: Participants in the delayed test-only control condition did not receive any instruction. On subsequent recall tests, participants in all three conditions were instructed to report as much information as possible about the offense. On the free recall test, feigning amnesia impaired memory for the video clip, but participants who were asked to feign crime-related amnesia outperformed controls. However, no differences between simulators and confessors were found on both correct cued recollection or on distortion and commission rates. We also explored whether inner speech might modulate memory for the crime. Inner speech traits were not found to be related to the simulating amnesia effect. Theoretical and practical implications of our results are discussed.

Can implicit measures detect source information in crime-related amnesia?

Participants who are asked to simulate amnesia for a mock crime have a weaker memory for this event when they have to give up their role as a feigner, than those who are not asked to feign memory loss. According to the source monitoring framework (SMF), this memory-undermining effect of simulating amnesia for a crime would be due to misattribution of the right source of information. However, we know that the content of self-generated information (e.g., feigned version of the crime) might be preserved and recognised over time as a result of elaborative cognitive processing. In the present study, we aimed to contrast these two explanations. We showed participants a mock crime video and we instructed them to either feign amnesia (simulators) or confess the mock crime (confessors). Next, a free recall memory test was administered. After one week, participants were asked to perform a personalised source monitoring task using the autobiographical Implicit Association Test (aIAT). As predicted, we found that simulators were able to discriminate the content of their self-generated feigned story of the crime from the original version. Moreover, simulators were quicker than confessors at the aIAT task. Practical and theoretical implications of our results are discussed.

Plausibility Judgments of Atypical Symptoms Across Cultures: an Explorative Study Among Western and Non-Western Experts.

Symptom validity tests (SVTs) are predicated on the assumption that overendorsement of atypical symptoms flags symptom exaggeration (i.e., questionable symptom validity). However, few studies have explored how practitioners from different cultural backgrounds evaluate such symptoms. We asked professionals working in Western (n = 56) and non-Western countries (n = 37) to rate the plausibility of uncommon symptoms taken from the Structured Inventory of Malingered Symptomatology (SIMS), dissociative symptoms from the Dissociative Experience Scale (DES-T), and standard symptoms (e.g., anxiety, depression) from the Brief Symptom Inventory-18 (BSI-18). Western and non-Western experts gave similar plausibility ratings to atypical, dissociative, and standard symptoms: both groups judged BSI-18 symptoms as significantly more plausible than either dissociative or atypical symptoms, while the latter two categories did not differ. Our results suggest that the strategy to detect symptom exaggeration by exploring overendorsement of atypical items might work in a non-western context as well.

Differentiating Factitious from Malingered Symptomatology: the Development of a Psychometric Approach.

Psychometric symptom validity assessment is becoming increasingly part and parcel of psychological and neuropsychological assessments. An unresolved and rarely addressed issue concerns the differentiation between factitious and malingered symptom presentations: present-day symptom validity tests can assess whether an examinee presents with noncredible symptomatology, but not why an examinee does so. We explored this issue by developing the Symptom and Disposition Interview (SDI); a symptom validity test that incorporates strategies intended to gauge internal incentives associated with factitious disorder. The merits of the SDI were explored and compared to a traditional symptom validity test (the Structured Inventory of Malingered Symptomatology) in two analogue studies, each with factitious and malingering conditions (n = 24-30 per condition) and a clinical control group (n = 34, n = 40). Overall, the results were positive: The SDI was as effective in detecting feigned symptom presentations as a traditional symptom validity test and superior in differentiating factitious from malingered symptom presentations. We conclude that the SDI is not ready for clinical use, but that psychometric approaches to the assessment of factitious symptomatology, such as the SDI, appear sufficiently promising to warrant future research.

Moral Reminders Do Not Reduce Symptom Over-Reporting Tendencies.

Is presenting patients with moral reminders prior to psychological testing a fruitful deterrence strategy for symptom over-reporting? We addressed this question in three ways. In study 1, we presented individuals seeking treatment for ADHD complaints (n = 24) with moral primes using the Mother Teresa Questionnaire and compared their scores on an index of symptom over-reporting (i.e., the Structured Inventory of Malingered Symptomatology, SIMS) with those of unprimed patient controls (n = 27). Moral primes slightly decreased SIMS scores, but the effect was not significant. In study 2, we took a different approach to activate moral categories: we recruited individuals seeking treatment for ADHD complaints and asked some of them to sign a moral contract (i.e., prime; n = 19) declaring that they would complete the tests in an honest way and compared their scores on the SIMS and standard clinical scales measuring self-reported psychopathology with those of unprimed patient controls (n = 17). Again, we found no convincing evidence that moral cues suppress symptom over-reporting. In study 3, we gave individuals from the general population (N = 132) positive, negative, or neutral moral primes and implicitly induced them to feign symptoms, after which they completed a brief validated version of the SIMS and an adapted version of the b Test (i.e., an underperformance measure). Again, primes did not affect over-reporting tendencies. Taken together, our findings illustrate that moral reminders are not going to be useful in clinical practice. Rather, they point towards the importance of studying contextual and individual difference factors that guide moral decision-making in patients and may be modified to discourage symptom over-reporting.

Biased Symptom Reporting and Antisocial Behaviour in Forensic Samples: A Weak Link.

In two studies (one with 57 forensic inpatients and one with 45 prisoners) the connection between biased symptom reporting and antisocial behaviour is explored. The findings are as follows: 1) the association between symptom over-reporting and antisocial features is a) present in self-report measures, but not in behavioural measures, and b) stronger in the punitive setting than in the therapeutic setting; and 2) participants who over-report symptoms a) are prone to attribute blame for their offence to mental disorders, and b) tend to report heightened levels of antisocial features, but the reverse is not true. The data provide little support for the inclusion of antisocial behaviour (i.e. antisocial personality disorder) as a signal of symptom over-reporting (i.e. malingering) in the Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition (DSM-5). The empirical literature on symptom over-reporting and antisocial/psychopathic behaviour is discussed and it is argued that the utility of antisocial behaviour as an indicator of biased symptom reporting is unacceptably low.

The Potential for False Memories is Bigger than What Brewin and Andrews Suggest.

Brewin and Andrews (2016) reviewed the literature on false memory propensity for childhood events. In this commentary, we critically evaluate their basic claim that proneness to false memories of childhood experiences is more limited than has been articulated in the literature. We show that Brewin and Andrews were selective in their inclusion of false memory studies, thereby ignoring relevant research related to autobiographical false memories. Equally important, and in contrast to what Brewin and Andrews claim, we show that implanted false memories elicited by misinformation are characterized by high confidence.

When Children are the Least Vulnerable to False Memories: A True Report or a Case of Autosuggestion?

In this case report, a legal case revolving around the reliability of statements given by a 6-year-old girl is described. She claimed to have witnessed her mother being murdered by her father. Two psychological experts provided diametrically opposed opinions about the reliability of her statements. One expert, a clinician, opined that the girl's statements were based on autosuggestion whereas the other expert, a memory researcher, stated that autosuggestion was unlikely to have played a role. This case and the analysis of the experts' opinions illustrate what may happen when experts in court are unaware of the recent literature on (false) memory. That is, recent studies show that autosuggestion is less likely to occur in young children than in older children and adults. The current case stresses the importance and implications of relying on memory experts in cases concerning the reliability of eyewitness statements.

On the alleged memory-undermining effects of daydreaming.

In three experiments, we examined the memory-undermining effects of daydreaming for (un)related stimuli. In Experiments 1 and 2, we tested whether daydreaming fosters forgetting of semantically interrelated material and hence, catalyzes false memory production. In Experiment 3, we examined the memory effects of different daydreaming instructions. In Experiment 1, daydreaming did not undermine correct recall of semantically interrelated words, nor did it affect false memories. In Experiment 2, we again failed to find that daydreaming exerted memory-undermining effects a. In Experiment 3, no memory effects were obtained using different daydreaming instructions. Together, our studies fail to show appreciable memory-undermining effects of daydreaming.

Adaptive memory: identifying the proximate roots of the survival processing advantage.

The current study examined the role of item-specific, relational, and elaborative processing on adaptive memory. Younger and older adults received the standard survival processing, a survival-short, or a pleasantness processing instruction. The survival-short condition was specifically included to lead to fewer possibilities to engage in elaborative processing. Furthermore, half of the presented words were categorized words to boost relational processing. Younger adults demonstrated the typical survival recall advantage in that standard survival processing instructions resulted in superior free recall performance than that of the survival-short and the pleasantness processing groups. Among older adults, no mnemonic benefit of standard survival processing relative to the survival-short or pleasantness processing groups was found. Furthermore, reducing the probability of elaborative processing (i.e., through the survival-short processing instructions) abolished the survival recall advantage. Our results thus provide further evidence for the role of item-specific, relational, and elaborative processing in the survival processing advantage.

The Structured Inventory of Malingered Symptomatology (SIMS): a systematic review and meta-analysis.

We meta-analytically reviewed studies that used the Structured Inventory of Malingered Symptomatology (SIMS) to detect feigned psychopathology. We present weighted mean diagnostic accuracy and predictive power indices in various populations, based on 31 studies, including 61 subsamples and 4009 SIMS protocols. In addition, we provide normative data of patients, claimants, defendants, nonclinical adults, and various experimental feigners, based on 41 studies, including 125 subsamples and 4810 SIMS protocols. We conclude that the SIMS (1) is able to differentiate well between instructed feigners and honest responders; (2) generates heightened scores in groups that are known to have a raised prevalence of feigning (e.g., offenders who claim crime-related amnesia); (3) may overestimate feigning in patients who suffer from schizophrenia, intellectual disability, or psychogenic non-epileptic seizures; and (4) is fairly robust against coaching. The diagnostic power of the traditional cut scores of the SIMS (i.e., > 14 and > 16) is not so much limited by their sensitivity­which is satisfactory­but rather by their substandard specificity. This, however, can be worked around by combining the SIMS with other symptom validity measures and by raising the cut score, although the latter solution sacrifices sensitivity for specificity.

Let's use those tests! Evaluations of crime-related amnesia claims.

Suspects awaiting trial often claim that they cannot remember important parts of their violent crimes. It is not unusual that forensic experts readily accept such claims and interpret them in terms of dissociative amnesia or, more specifically, a "red-out". This interpretation hinges on the assumption that heightened levels of stress implicated in violent crimes interfere with memory. We argue that the notion of red-out is a priori not plausible and that alternative interpretations-primarily malingering and substance-induced organic amnesia-should be considered and ruled out first before concluding that memory loss is dissociative in nature. We illustrate our point with four cases that superficially have the contours of red-out tragedies. We believe that, in such cases, neuropsychological tests and/or psychopharmacological information on dose-response relationships can assist forensic experts to exclude malingering or substance-induced amnesia. There is no reason for not using tests and tools from neuropsychology and psychopharmacology.

Susceptibility to misleading information under social pressure in schizophrenia.

Research looking at specific memory aberrations in the schizophrenia has primarily focused on their phenomenology using standardized semantic laboratory tasks. However, no study has investigated to what extent such aberrations have consequences for everyday episodic memories using more realistic false memory paradigms. Using a false memory paradigm where participants are presented with misleading suggestive information (Gudjonsson Suggestibility Scale), we investigated the susceptibility of patients with schizophrenia (n = 21) and healthy controls (n = 18) to post hoc misleading information acceptance and compliance. Patients with schizophrenia exhibited an increased susceptibility to go along with misleading suggestive items. Furthermore, they showed an increased tendency to change answers under conditions of social pressure. Underscoring previous findings on memory aberrations in schizophrenia, patients with schizophrenia had reduced levels of correct recognition (ie, true memory) relative to healthy controls. The effects remained stable when controlling for specific mediating variables such as symptom severity and intelligence in patients with schizophrenia. These findings are a first indication that social pressure and misleading information may impair source memory for everyday episodic memories in schizophrenia, and such impairment has clear consequences for treatment issues and forensic practice.