Directed forgetting of trauma cues in adult survivors of childhood sexual abuse with and without posttraumatic stress disorder

Emotional Memory in Post-traumatic Stress Disorder: A Systematic PRISMA Review of Controlled Studies

Background: Emotional memory is an adaptive process that improves the memorization of emotional events or stimuli. In Post-Traumatic Stress Disorder (PTSD), emotional memory may be altered, which in turn may affect symptoms. Having a clearer view of the processes of interaction between memory and emotional stimuli in PTSD may improve our knowledge of this disorder, and could create new therapeutic management tools. Thus, we performed a systematic review of the evidence of specific emotional memory in PTSD patients.

Method: Following PRISMA guidelines, a systematic review of MEDLINE, PsycInfo, and ScienceDirect was undertaken to identify controlled studies on emotional memory that used cognitive tasks on PTSD patients. The initial research was conducted from June 2017 to July 2017, and search terms included: Post-Traumatic Stress Disorder; PTSD; emotional memory; emotion; emotional; memory; and episodic memory.

Results: Eighteen studies reporting on 387 PTSD patients met the eligibility criteria. Among the studies selected, 11 observed specific memory processing in PTSD patients, such as a greater memorization of negative information, or a trend to false recognition of negative information. In addition, attentional and inhibition processing seem to play an important role in emotional memory in PTSD sufferers. Furthermore, other studies that did not find behavioral differences between PTSD and control groups nevertheless showed differences in both specific cerebral activities and neurohormone levels during emotional memory tasks.

Conclusion: This review has several limitations, including a limited number of controlled studies, small sample sizes, different tasks and methods. Nevertheless, the results of this systematic review provide interesting information on emotional memory for clinicians and researchers, as they seem to highlight facilitated memory processing for negative information in PTSD patients. This topic needs further controlled studies with sensitive behavioral tasks. Also, future studies may evaluate emotional memory after symptom amelioration.

Dissociation between working memory performance and proactive interference control in post-traumatic stress disorder

Deficits in working memory (WM) and cognitive control processes have been reported in post-traumatic stress disorder (PTSD), in addition to clinical symptoms such as hypervigilance, re-experiencing, and avoidance of trauma reminders. Given the uncontrollable nature of intrusive memories, an important question is whether PTSD is associated with altered control of interference in WM. Some studies also suggest that episodic memory shows a material-specific dissociation in PTSD, with greater impairments in verbal memory and relative sparing of nonverbal memory. It is unclear whether this dissociation applies to WM, as no studies have used identical task parameters across material. Here we tested 29 combat Veterans with PTSD and 29 age-matched control Veterans on a recent probes WM task with words and visual patterns in separate blocks. Participants studied four-item sets, followed by a probe stimulus that had been presented in the previous set (recent probe) or not (nonrecent probe). Participants with PTSD made more errors than controls, and this decrement was similar for verbal and visual stimuli. Proactive interference from items recently presented, but no longer relevant, was not significantly different in the PTSD group and showed no relationship to re-experiencing symptom severity. These results demonstrate that PTSD is not reliably associated with increased intrusions of irrelevant representations into WM when non-emotional stimuli are used. Future studies that use trauma-related material may provide insight into the flashbacks and intrusive thoughts that plague those with PTSD.

Patterns of Childhood Abuse and Neglect in a Representative German Population Sample

BACKGROUND

Different types of childhood maltreatment, like emotional abuse, emotional neglect, physical abuse, physical neglect and sexual abuse are interrelated because of their co-occurrence. Different patterns of childhood abuse and neglect are associated with the degree of severity of mental disorders in adulthood. The purpose of this study was (a) to identify different patterns of childhood maltreatment in a representative German community sample, (b) to replicate the patterns of childhood neglect and abuse recently found in a clinical German sample, (c) to examine whether participants reporting exposure to specific patterns of child maltreatment would report different levels of psychological distress, and (d) to compare the results of the typological approach and the results of a cumulative risk model based on our data set.

METHODS

In a cross-sectional survey conducted in 2010, a representative random sample of 2504 German participants aged between 14 and 92 years completed the Childhood Trauma Questionnaire (CTQ). General anxiety and depression were assessed by standardized questionnaires (GAD-2, PHQ-2). Cluster analysis was conducted with the CTQ-subscales to identify different patterns of childhood maltreatment.

RESULTS

Three different patterns of childhood abuse and neglect could be identified by cluster analysis. Cluster one showed low values on all CTQ-scales. Cluster two showed high values in emotional and physical neglect. Only cluster three showed high values in physical and sexual abuse. The three patterns of childhood maltreatment showed different degrees of depression (PHQ-2) and anxiety (GAD-2). Cluster one showed lowest levels of psychological distress, cluster three showed highest levels of mental distress.

CONCLUSION

The results show that different types of childhood maltreatment are interrelated and can be grouped into specific patterns of childhood abuse and neglect, which are associated with differing severity of psychological distress in adulthood. The results correspond to those recently found in a German clinical sample and support a typological approach in the research of maltreatment. While cumulative risk models focus on the number of maltreatment types, the typological approach takes the number as well as the severity of the maltreatment types into account. Thus, specific patterns of maltreatment can be examined with regard to specific long-term psychological consequences.

Forgetting of Trauma Cues in Adults Reporting Continuous or Recovered Memories of Childhood Sexual Abuse

According to betrayal trauma theory, adult survivors of childhood sexual abuse (CSA) who were molested by their caretakers (e.g., a father) are especially likely to dissociate (“repress”) their memories of abuse. Testing college students, some reporting CSA, DePrince and Freyd (2004) found that those scoring high on a dissociation questionnaire exhibited memory deficits for trauma words when they viewed these words under divided-attention conditions. Replicating DePrince and Freyd's procedure, we tested for memory deficits for trauma words relative to neutral words in adults reporting either continuous or recovered memories of CSA versus adults denying a history of CSA. A memory deficit for trauma words under divided attention was expected in the recovered-memory group. Results were inconsistent with this prediction, as all three groups exhibited better recall of trauma words than neutral words, irrespective of encoding conditions.

Failing to forget: inhibitory-control deficits compromise memory suppression in posttraumatic stress disorder

Most people have experienced distressing events that they would rather forget. Although memories of such events become less intrusive with time for the majority of people, those with posttraumatic stress disorder (PTSD) are afflicted by vivid, recurrent memories of their trauma. Often triggered by reminders in the daily environment, these memories can cause severe distress and impairment. We propose that difficulties with intrusive memories in PTSD arise in part from a deficit in engaging inhibitory control to suppress episodic retrieval. We tested this hypothesis by adapting the think/no-think paradigm to investigate voluntary memory suppression of aversive scenes cued by naturalistic reminders. Retrieval suppression was compromised significantly in PTSD patients, compared with trauma-exposed control participants. Furthermore, patients with the largest deficits in suppression-induced forgetting were also those with the most severe PTSD symptoms. These results raise the possibility that prefrontal mechanisms supporting inhibitory control over memory are impaired in PTSD.

False memory for trauma-related Deese-Roediger-McDermott lists in adolescents and adults with histories of child sexual abuse

The purpose of the present research was to examine Deese-Roediger-McDermott false memory for trauma-related and nontrauma-related lists in adolescents and adults with and without documented histories of child sexual abuse (CSA). Individual differences in psychopathology and adult attachment were also explored. Participants were administered free recall and recognition tests after hearing CSA, negative, neutral, and positive Deese-Roediger-McDermott lists. In free recall, CSA and negative lists produced the most false memory. In sharp contrast, for recognition, CSA lists enjoyed the highest d' scores. CSA-group adolescents who evinced greater posttraumatic stress disorder (PTSD) symptoms had higher rates of false memory compared to (a) non-CSA group adolescents with higher PTSD symptom scores (free recall), and (b) CSA-group adolescents with lower PTSD symptom scores (recognition). Regression analyses revealed that individuals with higher PTSD scores and greater fearful-avoidant attachment tendencies showed less proficient memory monitoring for CSA lists. Implications for trauma and memory development and for translational research are discussed.

Directed forgetting of negative self-referential information is difficult: an FMRI study

A large body of evidence suggested that both emotion and self-referential processing can enhance memory. However, it remains unclear how these two factors influence directed forgetting. This study speculates that directed forgetting of negative self-referential memory is more difficult than forgetting of other-referential memory. To verify this speculation, we combined the directed forgetting paradigm with the self-reference task. The behavioral result suggested that although both self-referential and other-referential information can be directly forgotten, less self-referential information can be forgotten than other-referential information. At the neural level, the forget instruction strongly activated the frontal cortex, suggesting that directed forgetting is not memory decay but an active process. In addition, compared with the negative other-referential information, forgetting of the negative self-referential information were associated with a more widespread activation, including the orbital frontal gyrus (BA47), the inferior frontal gyrus (BA45, BA44), and the middle frontal gyrus. Our results suggest that forgetting of the self-referential information seems to be a more demanding and difficult process.

Directed forgetting in post-traumatic-stress-disorder: a study of refugee immigrants in Germany

People with post-traumatic stress disorder (PTSD) often suffer from memory disturbances. In particular, previous studies suggest that PTSD patients perform atypically on tests of directed forgetting, which may be mediated by an altered emotional appraisal of the presented material. Also, a special role of dissociative symptoms in traumatized individuals’ memory performance has been suggested. Here, we investigate these issues in traumatized immigrants in Germany. In an item-method directed forgetting task, pictures were presented individually, each followed by an instruction to either remember or forget it. Later, recognition memory was tested for all pictures, regardless of initial instruction. Overall, the PTSD group’s discrimination accuracy was lower than the control group’s, as PTSD participants produced fewer hits and more false alarms, but the groups did not differ in directed forgetting itself. Moreover, the more negatively participants evaluated the stimuli, the less they were able to discriminate old from new items. Participants with higher dissociation scores were particularly poor at recognizing to-be-forgotten items. Results confirm PTSD patients’ general discrimination deficits, but provide no evidence for a distinct directed forgetting pattern in PTSD. Furthermore, data indicate that, in general, more negatively perceived items are discriminated with less accuracy than more positively appraised ones. Results are discussed in the larger context of emotion and stress-related modulations of episodic memory, with particular focus on the role of dissociative symptoms.

The effects of trauma exposure and posttraumatic stress disorder (PTSD) on the emotion-induced memory trade-off

Many past examinations of memory changes in individuals with posttraumatic stress disorder (PTSD) have focused on changes in memory for trauma. However, it is unclear if these mnemonic differences extend beyond the memory of the trauma to memory for other positive and negative information and if they are specific to individuals with PTSD or extend to other individuals who have experienced trauma. The present study examined the influences of trauma exposure and PTSD on an effect that may parallel tunnel memory in PTSD: the emotion-induced memory trade-off, whereby emotional aspects of an experience are remembered at the expense of the nonemotional context. Three groups of participants (25 with current PTSD, 27 who had experienced trauma but did not have current PTSD, and 25 controls who had neither experienced significant trauma nor met criteria for current PTSD) were shown complex visual scenes that included an item (positive, negative, or neutral) placed on a neutral background. Forty-five minutes later, participants underwent a recognition memory test for the items and backgrounds separately. An emotion-induced memory trade-off was said to occur when there was a significant difference in item and background memory for emotional scenes, but not for neutral scenes. Results indicated that people with PTSD, like the other groups, were more likely to remember positive and negative items than neutral items. Moreover, people with PTSD exhibited a memory trade-off comparable in magnitude to that exhibited by the non-trauma control group. In contrast, trauma-exposed people without a current diagnosis of PTSD did not show a trade-off, because they remembered items within scenes better than their accompanying contexts not only for emotional but also for neutral scenes. These results suggest that (1) the effect of emotion on memory for visual scenes is similar in people with PTSD and control participants, and (2) people who have experienced trauma, but do not have PTSD, may have a different way of attending to and remembering visual scenes, exhibiting less of a memory trade-off than either control participants or people with PTSD.

Intentional forgetting of emotional words after trauma: a study with victims of sexual assault

Following exposure to a trauma, people tend to experience intrusive thoughts and memories about the event. In order to investigate whether intrusive memories in the aftermath of trauma might be accounted for by an impaired ability to intentionally forget disturbing material, the present study used a modified Directed Forgetting task to examine intentional forgetting and intrusive recall of words in sexual assault victims and controls. By including words related to the trauma in addition to neutral, positive, and threat-related stimuli it was possible to test for trauma-specific effects. No difference between the Trauma and the Control group was found for correct recall of to-be-forgotten (F) words or to-be-remembered (R) words. However, when recalling words from R-list, the Trauma group mistakenly recalled significantly more trauma-specific words from F-list. “Intrusive“ recall of F-trauma words when asked to recall R-words was related to symptoms of post-traumatic stress disorder reported on the Impact of Event Scale and the Post-traumatic Diagnostic Scale. The results are discussed in term of a source-monitoring account.

ERP dynamics underlying successful directed forgetting of neutral but not negative pictures

Subjective experience suggests that negatively arousing memories are harder to control than neutral ones. Here, we investigate this issue in an item-cued directed forgetting experiment. Electroencephalogram event-related potentials (ERPs) were recorded as participants viewed un-arousing neutral and highly arousing negative photographs, each followed by a cue to remember or forget it. Directed forgetting, that is reduced recognition of 'to-be-forgotten' items, occurred for neutral but not negative pictures. ERPs revealed three underlying effects: first, during picture viewing a late parietal positive potential (LPP) was more pronounced for negative than for neutral pictures. Second, 'remember' cues were associated with larger LPPs than 'forget' cues. Third, an enhanced frontal positivity appeared for 'forget' cues. This frontal positivity was generated in right dorso-lateral prefrontal regions following neutral pictures and in medial frontal cortex following negative pictures. LPP magnitude when viewing negative pictures was correlated with reduced directed forgetting, whereas both the enhanced frontal positivity for forget cues and the larger parietal positivity for remember cues predicted more directed forgetting. This study indicates that both processes of selective rehearsal (parietal positivities) and frontally controlled inhibition contribute to successful directed forgetting. However, due to their deeper incidental processing, highly arousing negative pictures are exempt from directed forgetting.

Cognitive processes in dissociation: comment on Giesbrecht et al. (2008)

In their recent review "Cognitive Processes in Dissociation: An Analysis of Core Theoretical Assumptions," published in Psychological Bulletin, Giesbrecht, Lynn, Lilienfeld, and Merckelbach have challenged the widely accepted trauma theory of dissociation, which holds that dissociative symptoms are caused by traumatic stress. In doing so, the authors have outlined a series of links between various constructs--such as fantasy proneness, cognitive failures, absorption, suggestibility, altered information-processing, dissociation, and amnesia--claiming that these linkages lead to the false conclusion that trauma causes dissociation. A review of the literature, however, shows that these are not necessarily related constructs. Careful examination of their arguments reveals no basis for the conclusion that there is no association between trauma and dissociation. The current comment offers a critical review and rebuttal of Giesbrecht et al.'s argument that there is no relationship between trauma and dissociation.

Child maltreatment and memory

Exposure to childhood trauma, especially child maltreatment, has important implications for memory of emotionally distressing experiences. These implications stem from cognitive, socio-emotional, mental health, and neurobiological consequences of maltreatment and can be at least partially explained by current theories concerning the effects of childhood trauma. In this review, two main hypotheses are advanced: (a) Maltreatment in childhood is associated with especially robust memory for emotionally distressing material in many individuals, but (b) maltreatment can impair memory for such material in individuals who defensively avoid it. Support for these hypotheses comes from research on child abuse victims' memory and suggestibility regarding distressing but nonabusive events, memory for child abuse itself, and autobiographical memory. However, more direct investigations are needed to test precisely when and how childhood trauma affects memory for emotionally significant, distressing experiences. Legal implications and future directions are discussed.

Emotional arousal enhances word repetition priming

Three experiments were conducted to determine if emotional content increases repetition priming magnitude. In the study phase of Experiment 1, participants rated high-arousing negative (taboo) words and neutral words for concreteness. In the test phase, they made lexical decision judgements for the studied words intermixed with novel words (half taboo, half neutral) and pseudowords. In Experiment 2, low-arousing negative (LAN) words were substituted for the taboo words, and in Experiment 3 all three word types were used. Results showed significant priming in all experiments, as indicated by faster reaction times for studied words than for novel words. A priming × emotion interaction was found in Experiments 1 and 3, with greater priming for taboo relative to neutral words. The LAN words in Experiments 2 and 3 showed no difference in priming magnitude relative to the other word types. These results show selective enhancement of word repetition priming by emotional arousal.

Pavlovian eyeblink conditioning in combat veterans with and without post-traumatic stress disorder

Several recent studies have investigated relationships between post-traumatic stress disorder (PTSD) and learning and memory problems. These reports have found in general that not only does PTSD affect trauma-related memories, but when patients with PTSD are compared with similar trauma patients without PTSD, general memory impairments have been found. The present paper reports a study in which associative learning, using Pavlovian eyeblink conditioning, was investigated in combat veterans with and without chronic PTSD, using interstimulus intervals of 500 and 1000 msec in two separate experiments. Although several recent reports suggest that larger-magnitude autonomic conditioned responses occur in patients with PTSD during Pavlovian conditioning, the present study found evidence of impaired Pavlovian eyeblink conditioning in combat veterans with and without PTSD, compared to non-combat veterans. Although these data suggest that combat leads to an impaired associative learning process regardless of whether PTSD is apparent, a group of community-dwelling combat veterans not under medical treatment showed normal conditioning, suggesting that variables other than prior combat must also be involved.

Point-Counterpoint: Two Views on Traumatic Memories and Posttraumatic Stress Disorder

Recent books by Brewin (2003) and McNally (2003b) each reviewed the empirical literature on traumatic memories and posttraumatic stress disorder (PTSD). Although these authors reached similar conclusions on several topics, they differed on a number of important and controversial issues. In this article, Drs. Brewin and McNally are interviewed on these issues, and asked to comment on one another’s conclusions. Issues discussed include the nature of traumatic events and traumatic stress responses, the problem of malingering in PTSD research, the relative merits of contemporary cognitive models of PTSD, the issues of whether body memories and satanic cult abuse are genuine phenomena, and the question of whether memories can be repressed and later recovered. Implications for the assessment and treatment of PTSD are also discussed. The arguments for and against the various opinions provide fertile ground for stimulating further research into these controversial topics.

Implicit and explicit memory for trauma-related information in PTSD

Experiments on content-dependent memory abnormalities in PTSD suggest several conclusions. First, PTSD patients exhibit enhanced recall of words related to trauma relative to trauma-exposed persons with the disorder. Recognition tests, however, appear insensitive to these effects. Second, PTSD patients do not exhibit implicit memory biases for trauma cues on implicit memory tasks that are strongly influenced by perceptual (e.g., orthographic) aspects of input. They may, however, exhibit enhanced implicit memory for trauma-related material on conceptually more complex tasks. Third, directed forgetting research suggests that adult survivors of childhood sexual abuse who have PTSD exhibit memory deficits only for neutral and positive material, not for material related to their abuse. Psychiatrically healthy survivors exhibit normal memory performance in this paradigm. Fourth, autobiographical memory research indicates that trauma survivors, especially those with PTSD, are characterized by difficulties retrieving specific memories from their past in response to cue words. These findings are especially dramatic in Vietnam combat veterans whose self-presentational style suggests a fixation to the war and a failure of their autobiography to unfold.