Harald Merckelbach

Maastricht University, Maestricht, Limburg, Netherlands

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Publications (348)530.57 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose Epidemiological research on childhood sexual abuse (CSA) and its consequences in adult life mainly relies on retrospective reports. This study explores their consistency and the correlates of inconsistent CSA self-reports in a random population sample. Method A stratified subsample of 2,462 subjects (selected from a large-scale (N = 34,267) representative sample of Dutch adults aged 40 and beyond) participated in a two-phase online questionnaire survey on extra-familial CSA which was conducted on a four- to six-week interval. Subjects reporting CSA were overrepresented. Participants with consistent and inconsistent responses were compared with regard to demographics, family background, abuse severity, and clinical characteristics. Potential correlates of inconsistency were identified using logistic regression analysis. An additional questionnaire (Phase III) administered to inconsistent respondents explored possible reasons for their inconsistency. Results Of the 1,992 respondents who had reported extra-familial CSA during Phase I, 707 (35.5%) denied this in Phase II. Of the 2,462 respondents in Phase II, 727 (29.5%; 9.2% when considering sample stratification) gave a discrepant answer to the extra-familial sexual abuse item compared to their answers given in Phase I. Reports of less severe abuse, intra-familial CSA, and early parental separation predicted inconsistency. Reasons provided for inconsistency varied from misunderstanding (e.g., reporting intra-familial CSA rather than extra-familial CSA) to emotional motives (e.g., embarrassment, being overwhelmed) or practical considerations (e.g., lack of privacy while filling out the questionnaire). Conclusions Inconsistent self-reports of extra-familial sexual abuse occur on a substantial scale and are associated with less severe forms of abuse (lack of salience) or classification difficulties (perpetrator being a family member or not). Consistency tests and probing for clarifications or corrections should be routinely conducted in order to increase the quality of CSA epidemiological research.
    Social Psychiatry and Psychiatric Epidemiology 11/2014; · 2.86 Impact Factor
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    ABSTRACT: Sleep disturbances, fantasy proneness, cognitive failures, and dissociative symptoms are related to each other. However, the co-occurrence of these phenomena has been primarily studied in non-clinical samples. We investigated the correlations between these phenomena in dissociative identity disorder (DID) patients, post-traumatic stress disorder (PTSD) patients, and healthy controls. Both patient groups reported more sleep problems and lower sleep quality and displayed higher levels of fantasy proneness and cognitive failures than controls. However, the two patient groups did not differ with regard to these variables. Moreover, a higher level of unusual sleep experiences tended to predict participants belonging to the DID group, while specifically a lower sleep quality and more cognitive failures tended to predict participants belonging to the PTSD group.
    Frontiers in Psychiatry 09/2014; 5:19.
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    Anna Sagana, Melanie Sauerland, Harald Merckelbach
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    ABSTRACT: The aim of the current research was to identify conditions under which choice blindness in facial recognition decisions occurs. In five experiments, participants watched four mock-crime videos and made choices that were either evaluative (Experiment 1) or absolute in nature (Experiments 2a–c and 3). When participants were subsequently asked to motivate their choice, they were sometimes presented with choices they had not made. For evaluative decisions, concurrent (27%) and retrospective blindness rates (21%) were relatively low compared with previous studies. For absolute decisions, choice-blindness rates varied, depending on when exposure to the manipulated outcome took place (immediate: concurrent 32–35%, retrospective 0–6% [Experiments 2a–c]; 48 hours' delay: concurrent 68%, retrospective 39% [Experiment 3]). We argue that blindness for facial recognition decisions is more likely for evaluative decisions and for longer intervals between decision and manipulation and also for conditions of increased task complexity, which we interpret in terms of ambiguity. Copyright © 2014 John Wiley & Sons, Ltd.
    Applied Cognitive Psychology 08/2014; · 1.67 Impact Factor
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    ABSTRACT: Dalenberg et al. (2012) argued that convincing evidence (a) supports the longstanding trauma model (TM), which posits that early trauma plays a key role in the genesis of dissociation; and (b) refutes the fantasy model (FM), which posits that fantasy proneness, suggestibility, cognitive failures, and other variables foster dissociation. We review evidence bearing on Dalenberg et al.'s 8 predictions and find them largely wanting in empirical support. We contend that the authors repeat errors committed by many previous proponents of the TM, such as attributing a central etiological role to trauma in the absence of sufficient evidence. Specifically, Dalenberg et al. leap too quickly from correlational data to causal conclusions, do not adequately consider the lack of corroboration of abuse in many studies, and underestimate the relation between dissociation and false memories. Nevertheless, we identify points of agreement between the TM and FM regarding potential moderators and mediators of dissociative symptoms (e.g., family environment, biological vulnerabilities) and the hypothesis that dissociative identity disorder is a disorder of self-understanding. We acknowledge that trauma may play a causal role in dissociation but that this role is less central and specific than Dalenberg et al. contend. Finally, although a key assumption of the TM is dissociative amnesia, the notion that people can encode traumatic experiences without being able to recall them lacks strong empirical support. Accordingly, we conclude that the field should now abandon the simple trauma-dissociation model and embrace multifactorial models that accommodate the diversity of causes of dissociation and dissociative disorders. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
    Psychological Bulletin 05/2014; 140(3):896-910. · 15.58 Impact Factor
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    ABSTRACT: We investigated whether symptom overreporting affects the dose-response relationship between self-reported abuse severity and psychiatric symptoms in two samples. The first sample (N=599) consisted of adults who had previously reported to a public commission that they had been witnesses to or victims of childhood sexual abuse by Roman Catholic Church representatives. The second sample (N=1756) consisted of general population respondents who indicated that they had been victims of non-familial childhood sexual abuse. Using a web-based data collection procedure, both samples completed the Brief Symptom Inventory (BSI-18), items addressing abuse severity, and items flagging symptom overreporting. Adjusting for overreporting reduced the proportion of participants with clinically raised BSI-18 scores from 60% to 47% in sample 1 and from 26% to 22% in sample 2. Also, in both samples, normal range reporting participants exhibited the typical dose-response relationship between trauma severity and BSI-18 scores, whereas this pattern was largely non-significant in overreporting participants. Our findings show that symptom overreporting has a psychometric impact that may obscure relationships between clinically relevant variables and should therefore preferably be monitored in surveys.
    Psychiatry Research 03/2014; · 2.68 Impact Factor
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    Anna Sagana, Melanie Sauerland, Harald Merckelbach
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    ABSTRACT: Choice blindness refers to the phenomenon that people can be easily misled about the choices they made in the recent past. The aim of this study was to explore the cognitive mechanisms underlying choice blindness. Specifically, we tested whether memory impairment may account for choice blindness. A total of N = 88 participants provided sympathy ratings on 10-point scales for 20 female faces. Subsequently, participants motivated some of their ratings. However, on three trials, they were presented with sympathy ratings that deviated from their original ratings by three full scale points. On nearly 41% of the trials, participants failed to detect (i.e., were blind) the manipulation. After a short interval, participants were informed that some trials had been manipulated and were asked to recall their original ratings. Participants adopted the manipulated outcome in only 3% of the trials. Furthermore, the extent to which the original ratings were accurately remembered was not higher for detected as compared with non-detected trials. From a theoretical point of view our findings indicate that memory impairment does not fully account for blindness phenomena.
    Frontiers in Psychology 01/2014; 5:449. · 2.80 Impact Factor
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    ABSTRACT: Llewellyn has written a fascinating article about rapid eye movement (REM) dreams and how they promote the elaborative encoding of recent memories. The main message of her article is that hyperassociative and fluid cognitive processes during REM dreaming facilitate consolidation. We consider one potential implication of this analysis: the possibility that excessive or out-of-phase REM sleep fuels dissociative symptomatology. Further research is warranted to explore the psychopathological ramifications of Llewellyn's theory.
    Behavioral and Brain Sciences 12/2013; 36(6):630-1. · 18.57 Impact Factor
  • Applied Neuropsychology 11/2013; · 1.32 Impact Factor
  • Anna Sagana, Melanie Sauerland, Harald Merckelbach
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    ABSTRACT: In a field study, we examined choice blindness for eyewitnesses' facial recognition decisions. Seventy-one pedestrians were engaged in a conversation by two experimenters who pretended to be tourists in the center of a European city. After a short interval, pedestrians were asked to identify the two experimenters from separate simultaneous six-person photo lineups. Following each of the two forced-choice recognition decisions, they were confronted with their selection and asked to motivate their decision. However, for one of the recognition decisions, the chosen lineup member was exchanged with a previously unidentified member. Blindness for this identity manipulation occurred at the rate of 40.8%. Furthermore, the detection rate varied as a function of similarity (high vs. low) between the original choice and the manipulated outcome. Finally, choice manipulations undermined the confidence-accuracy relation for detectors to a greater degree than for blind participants. Stimulus ambiguity is discussed as a moderator of choice blindness. Copyright © 2013 John Wiley & Sons, Ltd.
    Behavioral Sciences & the Law 09/2013; · 0.96 Impact Factor
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    ABSTRACT: Across two experiments, we studied a phenomenon akin to choice blindness in the context of participants' accounts of their own history of norm-violating behaviors. In Experiment 1, N = 67 participants filled in an 18-item questionnaire about their history of norm-violating behaviors (QHNVB). Subsequently, they were questioned about four of their answers, two of which had covertly been manipulated by the experimenter. Of the 134 manipulations, 20 (14.9%) remained undetected concurrently and 13 were accepted in retrospect (9.7%). In Experiment 2 (N = 37), we inserted a one-week interval between questionnaire and interview. Twenty-seven (36.5%) of the 74 manipulations remained undetected concurrently and three were accepted in retrospect (8.1%). Data obtained in a four-week follow-up indicated that our manipulations may have long-term effects on participants' perception of their own history of norm-violating behaviors. Implications for the occurrence of false confessions during the course of an interrogation are discussed. Copyright © 2013 John Wiley & Sons, Ltd.
    Behavioral Sciences & the Law 04/2013; · 0.96 Impact Factor
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    ABSTRACT: 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.
    Memory 02/2013; · 2.09 Impact Factor
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    ABSTRACT: BACKGROUND: Dissociative disorders encompass a range of symptoms varying from severe absent-mindedness and memory problems to confusion about one's own identity. Recent studies suggest that these symptoms may be the by-products of a labile sleep-wake cycle. METHODS: In the current study, we explored this issue in patients suffering from insomnia (N=46). We investigated whether these patients have raised levels of dissociative symptoms and whether these are related to objective sleep parameters. Patients stayed for at least one night in a specialized sleep clinic, while sleep EEG data were obtained. In addition, they completed self-report measures on dissociative symptoms, psychological problems, and sleep characteristics. RESULTS: Dissociative symptom levels were elevated in patients suffering from insomnia, and were correlated with unusual sleep experiences and poor sleep quality. Longer REM sleep periods and less time spent awake during the night were predictive of dissociation. CONCLUSIONS: This is the first study to show that insomnia patients have raised dissociative symptom levels and that their dissociative symptoms are related to objective EEG parameters. These findings are important because they may inspire sleep-related treatment methods for dissociative disorders.
    Comprehensive psychiatry 01/2013; · 2.08 Impact Factor
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    ABSTRACT: Stress and stress hormones modulate memory formation in various ways that are relevant to our understanding of stress-related psychopathology, such as posttraumatic stress disorder (PTSD). Particular relevance is attributed to efficient memory formation sustained by the hippocampus and parahippocampus. This process is thought to reduce the occurrence of intrusions and flashbacks following trauma, but may be negatively affected by acute stress. Moreover, recent evidence suggests that the efficiency of visuo-spatial processing and learning based on the hippocampal area is related to PTSD symptoms. The current study investigated the effect of acute stress on spatial configuration learning using a spatial contextual cueing task (SCCT) known to heavily rely on structures in the parahippocampus. Acute stress was induced by subjecting participants (N = 34) to the Maastricht Acute Stress Test (MAST). Following a counterbalanced within-subject approach, the effects of stress and the ensuing hormonal (i.e., cortisol) activity on subsequent SCCT performance were compared to SCCT performance following a no-stress control condition. Acute stress did not impact SCCT learning overall, but opposing effects emerged for high versus low cortisol responders to the MAST. Learning scores following stress were reduced in low cortisol responders, while high cortisol-responding participants showed improved learning. The effects of stress on spatial configuration learning were moderated by the magnitude of endogenous cortisol secretion. These findings suggest a possible mechanism by which cortisol responses serve an adaptive function during stress and trauma, and this may prove to be a promising route for future research in this area.
    European Journal of Psychotraumatology 01/2013; 4.
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    ABSTRACT: Emotional stimuli draw attention to such an extent that they hamper the processing of subsequent signals, a phenomenon termed emotion-induced blindness (EIB). As depersonalization is associated with self-reported attenuated emotional responses, the present study explored whether individuals scoring high on the Cambridge Depersonalization Scale (CDS; n=15) exhibit a diminished EIB effect relative to low CDS scoring individuals (n=15), and whether attentional processes reflected in event-related potentials are implicated in this effect. We obtained an EIB effect such that emotional distractors that preceded targets with a lag of 200ms reduced correct detection of targets. Although the magnitude of this effect was similar for high and low CDS participants, high CDS participants exhibited a lower ERP amplitude at the frontal lead in the 200-300ms window than did low CDS individuals to targets that followed emotional versus neutral distractors (p<.05). This latter effect was related to the Alienation factor of the CDS (p<.05). This pattern suggests that difficulties in the discrimination between emotional and neutral stimuli relate to the feeling of unreality in depersonalization.
    Psychiatry Research 11/2012; · 2.68 Impact Factor
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    ABSTRACT: Traditionally, recovered memories of childhood sexual abuse (CSA) have been classified as those emerging spontaneously versus those surfacing during the course of suggestive therapy. There are indications that reinterpretation of memories might be a third route to recovered memories. Thus, recovered memories do not form a homogeneous category. Nevertheless, the conceptual distinctions between the various types of recovered memories remain difficult for researchers and clinicians. With this in mind, the current study explored whether recovered memories can be reliably classified. We found that classification is rather problematic in a subset of cases. To reduce potential bias, we urge for the development and subsequent use of a more reliable classification system and multiple expert raters in research on recovered memories.
    Consciousness and Cognition 10/2012; 21(4):1640-1643. · 2.31 Impact Factor
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    ABSTRACT: The dual-representation model of posttraumatic stress disorder (PTSD; Brewin, Gregory, Lipton, & Burgess, Psychological Review, 117, 210-232 2010) argues that intrusions occur when people fail to construct context-based representations during adverse experiences. The present study tested a specific prediction flowing from this model. In particular, we investigated whether the efficiency of temporal-lobe-based spatial configuration learning would account for individual differences in intrusive experiences and physiological reactivity in the laboratory. Participants (N = 82) completed the contextual cuing paradigm, which assesses spatial configuration learning that is believed to depend on associative encoding in the parahippocampus. They were then shown a trauma film. Afterward, startle responses were quantified during presentation of trauma reminder pictures versus unrelated neutral and emotional pictures. PTSD symptoms were recorded in the week following participation. Better configuration learning performance was associated with fewer perceptual intrusions, r = −.33, p < .01, but was unrelated to physiological responses to trauma reminder images (ps > .46) and had no direct effect on intrusion-related distress and overall PTSD symptoms, rs > −.12, ps > .29. However, configuration learning performance tended to be associated with reduced physiological responses to unrelated negative images, r = −.20, p = .07. Thus, while spatial configuration learning appears to be unrelated to affective responding to trauma reminders, our overall findings support the idea that the context-based memory system helps to reduce intrusions.
    Cognitive, Affective, & Behavioral Neuroscience. 09/2012;
  • Harald Merckelbach, Thomas Merten
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    ABSTRACT: This paper proposes that malingered symptoms may become internalized due to the self-deceptive power of cognitive dissonance. Studies demonstrating how other-deception may turn into self-deception are briefly discussed, as are clinical notions about the overlap between malingering and medically unexplained symptoms. In our view this literature showcases the relevance of cognitive dissonance for research on malingering. A cognitive dissonance perspective may help to clarify how ambiguous sensations may escalate into subjectively compelling symptoms. This perspective suggests that malingered symptom reports are more than just a complication during psychological evaluation. It may generate new research avenues and may clarify practically relevant issues.
    The Clinical Neuropsychologist 08/2012; 26(7):1217-29. · 1.68 Impact Factor
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    Thomas Meyer, Tom Smeets, Timo Giesbrecht, Harald Merckelbach
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    ABSTRACT: A widespread assumption in research and clinical practice is that cognitive reappraisal is a healthy and successful emotion regulation strategy, while expressive suppression is ineffective and has non-favourable consequences (e.g., decreased positive affect, higher physiological arousal). However, little is known about the consequences of reappraisal and expressive suppression for everyday affect. We investigated affective consequences of habitual reappraisal and expressive suppression in undergraduates (n=87), and sampled affect characteristics for 24h. Moreover, we quantified affective recovery from viewing an aversive video fragment. Habitual reappraisal was associated with lowered emotional arousal (but not valence), both in terms of diurnal affect levels and positive and negative responses to the emotional provocation task. This pattern contravenes the popular assumption that reappraisal has generally favourable consequences. Additionally, in contrast to the alleged non-favourable consequences of habitual expressive suppression, the current study failed to find a relation between expressive suppression, diurnal affect levels and affective recovery. This suggests that the detrimental effects of expressive suppression are limited in duration. Collectively, our results emphasise that the everyday consequences of emotion regulation for affect merits systematic research, for instance by using more naturalistic and prolonged interventions.
    Psychiatry Research 06/2012; · 2.68 Impact Factor
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    ABSTRACT: 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.
    Comprehensive psychiatry 06/2012; · 2.08 Impact Factor
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    ABSTRACT: Stress-related research has employed several procedures to activate the human stress system. Two of the most commonly used laboratory paradigms are the Trier Social Stress Test (TSST) and the Cold Pressor Test (CPT). We combined their most stressful features to create a simple laboratory stress test capable of eliciting strong autonomic and glucocorticoid stress responses. In comparison with the CPT and its variations, our stress tool (labeled the Maastricht Acute Stress Test; MAST) was found to yield superior salivary cortisol responses, while being equally effective in eliciting subjective stress reactions and (systolic and diastolic) blood pressure increases (study 1; N=80). In study 2 (N=20), we directly compared the effectiveness of the MAST and TSST and found that both methods elicited similar subjective, salivary alpha-amylase, and salivary cortisol stress responses. Finally, we developed and evaluated an appropriate no-stress control version of the MAST that was similar to the stress version, although it did not comprise stressful components (study 3; N=40). Collectively, our results confirm the effectiveness of the MAST in terms of subjective, autonomic, and - most importantly - glucocorticoid stress responses. Thus, as a brief and simple stress protocol, the MAST holds considerable promise for future research.
    Psychoneuroendocrinology 05/2012; · 5.59 Impact Factor

Publication Stats

4k Citations
530.57 Total Impact Points

Institutions

  • 1987–2014
    • Maastricht University
      • • Faculty of Psychology and Neuroscience
      • • Experimentele Klinische Psychologie
      • • Algemene Heelkunde
      Maestricht, Limburg, Netherlands
  • 2010
    • Albert Einstein College of Medicine
      New York City, New York, United States
  • 2008
    • Sundsvall Hospital
      Sundsvall, Västernorrland, Sweden
    • Ghent University
      • Department of Experimental Clinical and Health Psychology
      Gand, Flanders, Belgium
  • 2006
    • Erasmus Universiteit Rotterdam
      • Institute of Psychology (IOP)
      Rotterdam, South Holland, Netherlands
  • 1994
    • University of Amsterdam
      • Department of Clinical Psychology
      Amsterdamo, North Holland, Netherlands
  • 1993
    • Transnationale Universiteit Limburg
      Amsterdam, New York, United States
  • 1989
    • Universiteit Utrecht
      • Department of Psychiatry
      Utrecht, Utrecht, Netherlands
  • 1987–1988
    • Katholieke Hogeschool Limburg
      Limburg, Walloon Region, Belgium