The efficacy of a working memory training in substance use patients: A randomized double-blind placebo-controlled clinical trial.

INTRODUCTION: Substance use disorder patients show impairments in working memory (WM) functioning. Previous findings indicate that a WM training results in improvements of working memory capacity (WMC) and in decreased clinical symptoms in a range of mental disorders, including alcohol use disorder. METHOD: The aim of the current study is to investigate the efficacy of a 24-session WM training in addition to treatment as usual on craving, WMC, substance use, impulsivity, attention bias, and psychopathology using a randomized double-blind placebo-controlled trial. Inpatients (n = 180) diagnosed with an alcohol, cocaine, or cannabis use disorder were included. RESULTS: Although the WM training resulted in better scores on the trained tasks in both groups, the placebo training resulted in a better or equal WMC compared to the experimental training, as measured with two nontrained transfer tasks. The WM training had no effect on craving, substance use, impulsivity, attention bias, and psychopathology. CONCLUSION: Overall, we did not find evidence for the efficacy of WM training on WMC or clinical symptoms as compared to a placebo training in a population of substance use disorder patients. Future research needs to investigate further whether WMC is an important factor that is associated with substance-abuse-related behavior, and whether working memory training could be useful in substance use disorders.

A working memory training to decrease rumination in depressed and anxious individuals: a double-blind randomized controlled trial.

BACKGROUND: Rumination is one of the hallmark characteristics of both anxiety disorders and depression, and has been linked to deficient executive functioning, particularly working memory (WM). Previous findings show that working memory capacity can be increased through training. METHODS: The current study explored whether an adaptive stand-alone WM training could increase WMC and consequently reduce rumination, anxiety and depression by means of a double-blind randomized controlled trial in a sample of 98 patients with symptoms of anxiety and/or depression. RESULTS: No positive effect of training on WMC was found. In addition, the results show that a WM training was not associated with a reduction of rumination, depression, nor anxiety. LIMITATIONS: The high drop-out rate in both groups (20.11% from pre- to post-training) and the overrepresentation of men and use of anti-depressants in the placebo group might have influenced the results. Furthermore, expectations and perceptions about the training might have interacted with performance on WM tasks. CONCLUSIONS: Overall, results show that a stand-alone WM training in patients with symptoms of anxiety and/or depression does not result in reduced rumination nor in reduced symptoms of depression and anxiety. We discuss potential explanations for these findings.

Emotional and non-emotional memories are suppressible under direct suppression instructions.

Research on retrieval suppression has produced varying results concerning whether negatively valenced memories are more or less suppressible than neutral memories. This variability may arise if, across studies, participants adopt different approaches to memory control. Cognitive and neurobiological research points to two mechanisms that achieve retrieval suppression: thought-substitution and direct suppression (Benoit & Anderson, 2012; Bergström, de Fockert, & Richardson-Klavehn, 2009). Using the Think/No-think paradigm, this study examined whether participants can inhibit neutral and negatively valenced memories, using a uniform direct suppression strategy. Importantly, when strategy was controlled, negative and neutral items were comparably inhibited. Participants reported high compliance with direct suppression instructions, and success at controlling awareness predicted forgetting. These findings provide the first evidence that direct suppression can impair negatively valenced events, and suggest that variability in forgetting negative memories in prior studies is unlikely to arise from difficulty using direct suppression to control emotionally negative experiences.

Reduced specificity of negative autobiographical memories in repressive coping.

The current study examined memory specificity of autobiographical memories in individuals with and without a repressive coping style. It seems conceivable that reduced memory specificity may be a way to reduce accessibility of negative experiences, one of the hallmark features of a repressive coping style. It was therefore hypothesized that repressors would show reduced specificity when retrieving negative memories. In order to study memory specificity, participants (N = 103) performed the autobiographical memory test. Results showed that individuals with a repressive coping style were significantly less specific in retrieving negative experiences, relative to control groups of low anxious, high anxious, and defensive high anxious individuals. This result was restricted to negative memory retrieval, as participants did not differ in memory specificity for positive experiences. These results show that repressors retrieve negative autobiographical memories in an overgeneral way, possibly in order to avoid negative affect.

User validation of an empathic virtual buddy against cyberbullying.

People are able to comfort others by talking about their problems. In our research, we are exploring whether computers can provide social support in a similar manner. Recently, we proposed a design for an empathic virtual buddy that supports victims of cyberbullying. To validate our approach in providing social support and to gather feedback from potential users, we performed an experiment (N = 30) to compare interaction with the buddy to reading a text. Both the buddy and the text received high scores; scores for the buddy were consistently higher. The difference was significant for the extent to which feelings were taken into account. These results indicate that participants liked to interact with the buddy and that they recognized the emotional cues emitted by the buddy, thus validating our approach in comforting users.

Brooding deficits in memory: focusing attention improves subsequent recall.

Ruminative habits of thought about one's problems and the resulting consequences are correlated with symptoms of depression and cognitive biases (Nolen-Hoeksema, Wisco, & Lyubomirsky, 2008). In our orienting task, brooders and non-brooders concentrated on self-focusing phrases while they were also exposed to neutral target words. On each trial in the unfocused condition, participants saw and then reported the target before concentrating on the phrase; in the focused condition, the target was reported after phrase concentration. A brooding-related deficit on a subsequent unexpected test of free and forced recall was obtained in the unfocused condition only. Brooders recalled more successfully in the focused than in the unfocused condition. Thus, impaired recall of material unrelated to self-concerns may be corrected in situations that constrain attention.

Cognitive underpinnings of recovered memories of childhood abuse.

Recent research on recovered memories of childhood sexual abuse has shown that there are at least two types of recovered memory experiences: those that are gradually recovered within the context of suggestive therapy and those that are spontaneously recovered, without extensive prompting or explicit attempts to reconstruct the past. These recovered memory experiences have different origins, with people who recover memories through suggestive therapy being more prone to forming false memories, and with people who report spontaneously recovered memories being more prone to forgetting prior instances of remembering. Additionally, the two types of recovered memory experiences are linked to differences in corroborative evidence, implying that memories recovered spontaneously, outside of suggestive therapy, are more likely to correspond to genuine abuse events. This chapter highlights the background of the recovered memory debate, summarizes recent studies with individuals reporting recovered memory experiences and points towards applications in the justice system and in clinical practice.

Cognitive mechanisms underlying recovered-memory experiences of childhood sexual abuse.

People sometimes report recovering long-forgotten memories of childhood sexual abuse. The memory mechanisms that lead to such reports are not well understood, and the authenticity of recovered memories has often been challenged. We identified two subgroups of people reporting recovered memories of childhood sexual abuse. These subgroups differed dramatically in their cognitive profiles: People who recovered memories of abuse through suggestive therapy exhibited a heightened susceptibility to the construction of false memories, but showed no tendency to underestimate their prior remembering. Conversely, people who recovered memories of abuse spontaneously showed a heightened proneness to forget prior incidences of remembering, but exhibited no increased susceptibility to false memories. This double dissociation points to mechanisms that underlie recovered-memory experiences and indicates that recovered memories may at times be fictitious and may at other times be authentic.

A New Solution to the Recovered Memory Debate.

The controversy regarding recovered memories of childhood sexual abuse (CSA) has been characterized by two perspectives. According to one perspective, some people repress their memories of abuse because these experiences have been so emotionally traumatic, and they become capable of recalling the CSA only when it is psychologically safe to do so many years later. According to the other perspective, many reports of recovered memories of sexual abuse are false memories, often inadvertently fostered by therapists. In this article, we provide evidence for a third interpretation that applies to a subset of people reporting recollections of CSA; it does not require the concepts of repression, trauma, or false memory. These people did not experience their CSA as traumatic; they either failed to think about their abuse for years or forgot their previous recollections, and they recalled their CSA spontaneously after encountering reminders outside of psychotherapy. Their recovered memories are corroborated at the same rate as those of people who never forgot their abuse. Hence, recalling CSA after many years is not the same thing as having recalled a previously repressed memory of trauma.

Lasting false beliefs and their behavioral consequences.

False beliefs and memories can affect people's attitudes, at least in the short term. But can they produce real changes in behavior? This study explored whether falsely suggesting to subjects that they had experienced a food-related event in their childhood would lead to a change in their behavior shortly after the suggestion and up to 4 months later. We falsely suggested to 180 subjects that, as children, they had gotten ill after eating egg salad. Results showed that, after this manipulation, a significant minority of subjects came to believe they had experienced this childhood event even though they had initially denied having experienced it. This newfound autobiographical belief was accompanied by the intent to avoid egg salad, and also by significantly reduced consumption of egg-salad sandwiches, both immediately and 4 months after the false suggestion. The false suggestion of a childhood event can lead to persistent false beliefs that have lasting behavioral consequences.

Autobiographical memory specificity after manipulating retrieval cues in adults reporting childhood sexual abuse.

Traumatized samples have relative difficulty in generating specific autobiographical memories on a cue word task, compared to nonexposed controls. Simultaneously, trauma is associated with highly specific intrusive trauma memories in day-to-day life. Possibly, day-to-day intrusions and memories generated to cue words rely on different retrieval processes, with the former dependent on close associations between retrieval cues and specific memory representations (direct retrieval), and the latter on iterative retrieval cycles through a hierarchical memory system (generative retrieval). This study investigated this distinction using two versions of the cue word task, designed to promote generative and direct retrieval, respectively, in participants with or without a history of child sexual abuse (CSA). The data demonstrated that CSA participants were less specific than nonabused controls to generative retrieval cues, but this difference disappeared with direct retrieval cues. This interaction was stronger in CSA participants with relatively greater posttraumatic stress and remained significant when participants with past or current major depressive disorder were excluded and also when only those participants with corroborated CSA were included.

Forgetting unwanted memories: directed forgetting and thought suppression methods.

Experimental psychopathologists have tested hypotheses regarding mechanisms that ought to be operative if victims possess skills for forgetting material related to trauma. In this article, we review research on directed forgetting and thought suppression paradigms, concentrating on laboratory studies involving attempts by individuals reporting trauma histories to forget emotionally negative material. Most studies have shown that trauma survivors, especially those with post-traumatic stress disorder, are characterized by a breakdown in the ability to forget disturbing material. Studies on individuals reporting repressed or recovered memories of trauma have not confirmed predictions regarding heightened forgetting skills for trauma-related words. However, recent research on suppressing disturbing autobiographical memories suggests that people who report spontaneously recalling childhood abuse outside of psychotherapy may, indeed, possess skills for not thinking about disturbing material.

No evidence for verbal learning impairments in women with a history of childhood abuse.

We examined verbal learning in 54 women with a history of childhood abuse and 40 women without trauma history. Although women with a history of abuse reported higher levels of psychological distress than controls, the two groups did not differ in their verbal learning performance.

Linking thought suppression and recovered memories of childhood sexual abuse.

There are two types of recovered memories: those that gradually return in recovered memory therapy and those that are spontaneously recovered outside the context of therapy. In the current study, we employed a thought suppression paradigm, with autobiographical experiences as target thoughts, to test whether individuals reporting spontaneously recovered memories of childhood sexual abuse (CSA) are more adept at suppressing positive and anxious autobiographical thoughts, relative to individuals reporting CSA memories recovered in therapy, relative to individuals with continuous abuse memories, and relative to controls reporting no history of abuse. Results showed that people reporting spontaneously recovered memories are superior in suppressing anxious autobiographical thoughts, both in the short term and long term (7 days). Our findings may partly explain why people with spontaneous CSA memories have the subjective impression that they have "repressed" their CSA memories for many years.

The dissociative experiences taxon is related to fantasy proneness.

Some authors have argued that nonpathological dissociation should be distinguished from a taxon form of pathological dissociation, which is indexed by the Dissociative Experiences Scale Taxon (DES-T). We tested to what extent DES-T scores are independent from fantasy immersion and whether DES-T scores are uniquely related to trauma self-reports. To this end, subsamples of undergraduate students (n = 930), healthy adults (n = 20), schizophrenic patients (n = 22), borderline personality disordered patients (n = 20), patients with mood disorder without psychosis (n = 19), and women with a history of childhood sexual abuse (n = 55) completed the Dissociative Experiences Scale and a measure of fantasy immersion. DES-T scores were related to absorption and fantasy immersion to a lesser extent than the original DES. However, the fact that nontrivial percentages within all groups, except for the healthy adults, were classified as taxon members casts doubts on the assumption that DES-T is a reliable index of pathological dissociation. Also, we found that the DES-T was not exclusively related to reports of childhood sexual abuse.

Suppression of intrusive thoughts and working memory capacity in repressive coping.

Previous research using a thought suppression paradigm found that repressors are more skilled in suppressing anxious autobiographical thoughts than low anxious, high anxious, and defensive high anxious people. Another line of research showed that individual differences in working memory capacity are related to the ability to intentionally suppress intrusive thoughts. This study aimed at combining these findings and sought to investigate whether repressors' superior ability to suppress intrusive thoughts is related to a larger working memory capacity. Results indicate that in a thought suppression paradigm, repressors report fewer intrusive thoughts for their most anxious experiences than participants in the 3 other subgroups. Furthermore, the superior ability of repressors to avoid intrusive thoughts can be explained largely by their higher working memory capacity.

The reality of recovered memories: corroborating continuous and discontinuous memories of childhood sexual abuse.

Although controversy surrounds the relative authenticity of discontinuous versus continuous memories of childhood sexual abuse (CSA), little is known about whether such memories differ in their likelihood of corroborative evidence. Individuals reporting CSA memories were interviewed, and two independent raters attempted to find corroborative information for the allegations. Continuous CSA memories and discontinuous memories that were unexpectedly recalled outside therapy were more likely to be corroborated than anticipated discontinuous memories recovered in therapy. Evidence that suggestion during therapy possibly mediates these differences comes from the additional finding that individuals who recalled the memories outside therapy were markedly more surprised at the existence of their memories than were individuals who initially recalled the memories in therapy. These results indicate that discontinuous CSA memories spontaneously retrieved outside of therapy may be accurate, while implicating expectations arising from suggestions during therapy in producing false CSA memories.

Detection of feigned cognitive dysfunction using special malinger tests: a simulation study in naïve and coached malingerers.

The aim of the present study was to compare the accuracy of the Amsterdam Short Term Memory (ASTM) test with that of the Structured Inventory of the Malingered Symptomatology (SIMS) in detecting feigning of cognitive dysfunction in naïve and coached participants. Ninety undergraduate students were administered the ASTM and the SIMS and asked to respond honestly (controls; n = 30), or instructed to malinger cognitive dysfunction due to head injury. Before the both instruments were administered, naïve malingerers received no further information (n = 30), whereas coached malingerers were given some information about brain injury and a warning not to exaggerate symptoms (n = 30). Both tests correctly classified 90% of the naïve malingerers. The ASTM detected 70% of the coached malingerers, whereas the SIMS continued to detect 90% of them. The findings suggest that coaching undermines the diagnostic accuracy of the ASTM, but does not seem to influence the accuracy of the SIMS.

Delayed recall of childhood sexual abuse memories and the awakening rise and diurnal pattern of cortisol.

Traumatic stress associated with childhood sexual abuse (CSA) may result in chronic alterations of stress-sensitive neurochemical systems (e.g., the hypothalamic-pituitary-adrenal axis and sympathetic-adrenal medullary activity). Some authors have suggested that these alterations might help explain why some individuals, after a period of inability to remember, demonstrate delayed recall of CSA memories (i.e., "recovered" memories). The present study is the first study that explored morning cortisol responses and circadian cortisol profiles among women with recovered (n=7), repressed (n=8), or continuous (n=6) memories of CSA and women without a history of CSA (n=9). Although there were group differences in current depression and post-traumatic stress symptoms, we found no differences in cortisol awakening response or daytime profile between women reporting recovered, repressed, or continuous memories of CSA as compared to women without a history of CSA. Implications for neurobiological models intended to explain the delayed recall of CSA are discussed.