Schizophrenia, dissociation, and consciousness

Current thinking suggests that dissociation could be a significant comorbid diagnosis in a proportion of schizophrenic patients with a history of trauma. This potentially may explain the term “schizophrenia” in its original definition by Bleuler, as influenced by his clinical experience and personal view. Additionally, recent findings suggest a partial overlap between dissociative symptoms and the positive symptoms of schizophrenia, which could be explained by inhibitory deficits. In this context, the process of dissociation could serve as an important conceptual framework for understanding schizophrenia, which is supported by current neuroimaging studies and research of corollary discharges. These data indicate that the original conception of “split mind” may be relevant in an updated context. Finally, recent data suggest that the phenomenal aspects of dissociation and conscious disintegration could be related to underlying disruptions of connectivity patterns and neural integration.     

Dissociation in the laboratory: a comparison of strategies

Several methods for inducing dissociation in the laboratory were examined in a sample of 78 undergraduate students. Participants scoring high or low on the Dissociative Experiences Scale participated in three dissociation challenge conditions: (a) dot-staring task, (b) administration of pulsed photic and audio stimulation and (c) stimulus deprivation. Participants recorded their dissociative experiences both before and after each of the three challenge conditions. Across conditions, high DES participants reported significantly more dissociative sensations than low DES participants, even after controlling for pre-challenge dissociation. Moreover, regardless of DES status, pulsed photo and audio stimulation produced the greatest level of dissociative symptoms. The findings suggest that the induction of dissociative symptoms in a nonclinical sample is easily accomplished in the laboratory and that those who report more dissociative symptoms in their day-to-day life exhibit more pronounced dissociative symptoms when undergoing dissociative challenge in the laboratory. Implications for the study and treatment of dissociative symptoms are discussed.     

Dissociative Tendencies, Attention, and Memory

Two groups of college students were selected on the basis of their scores on the Dissociative Experiences Scale (DES). The high-DES group (score > 20, M = 29.6; n = 54) and low-DES group (score < 10, M = 5.1; n = 54) both completed the standard and a new dual-task version of the Stroop ink-naming task with xs (baseline condition) and color, neutral, and emotionally charged words. Free recall results indicated that high-DES participants remembered fewer emotionally charged words than low-DES participants. We found a crossover interaction for Stroop interference: High-DES participants showed more interference (conflicting color — baseline latency for ink naming) in a selective-attention Stroop task and less interference in the dual-task Stroop task. The interaction between attentional context and dissociation for Stroop interference and the free recall results are consistent with a cognitive-environments view of dissociative tendencies. In this view, dissociative tendencies, which have been otherwise speculated to be largely deleterious, can be advantageous in certain contexts.     

Electrophysiological correlates of dispositional mindfulness: A quantitative and complexity EEG study

While growing evidence supports that dispositional mindfulness relates to psychological health and cognitive enhancement, to date there have been only a few attempts to characterize its neural underpinnings. In the present study, we aimed at exploring the electrophysiological (EEG) signature of dispositional mindfulness using quantitative and complexity measures of EEG during resting state and while performing a learning task. Hundred twenty participants were assessed with the Five Facet Mindfulness Questionnaire and underwent 5 min eyes-closed resting state and 5 min at task EEG recording. We hypothesized that high mindfulness individuals would show patterns of brain activity related to (a) lower involvement of the default mode network (DMN) at rest (reduced frontal gamma power) and (b) a state of ‘task readiness’ reflected in a more similar pattern from rest to task (reduced overall q-EEG power at rest but not at task), as compared to their low mindfulness counterparts. Dispositional mindfulness was significantly linked to reduced frontal gamma power at rest and lower overall power during rest but not at task. In addition, we found a trend towards higher entropy during task performance in mindful individuals, which has recently been reported during mindfulness meditation. Altogether, our results add to those from expert meditators to show that high (dispositional) mindfulness seems to have a specific electrophysiological pattern characteristic of less involvement of the DMN and mind-wandering processes.     

Sleep normalization and decrease in dissociative experiences: evaluation in an inpatient sample

We conducted a longitudinal study to investigate the relation between sleep experiences and dissociative symptoms in a mixed inpatient sample at a private clinic evaluated on arrival and at discharge 6 to 8 weeks later. Using hierarchical regression analyses and structural equation modeling, we found a link between sleep experiences and dissociative symptoms and determined that specifically decreases in narcoleptic experiences rather than insomnia accompany a reduction in dissociative symptoms. Although sleep improvements were associated with a general reduction in psychopathology, this reduction could not fully account for the substantial and specific effect that we found for dissociation. Our findings are consistent with Watson's (2001) hypothesis that disruptions in the sleep-wake cycle lead to intrusions of sleep phenomena into waking consciousness, resulting in dissociative experiences. Accordingly, sleep hygiene may contribute to the treatment or prevention of dissociative symptoms.     

Psychophysiological Synchrony During Verbal Interaction in Romantic Relationships

Previous studies about romantic relationships have shown that the reciprocal influence between partners occurs not only at the behavioral and socio‐emotional levels, but also at the psychophysiological level. This reciprocal influence is expressed in a pattern of physiological synchrony between partners (i.e., coordinated dynamics of the physiological time series). The main aim of the present study was to explore the presence of a pattern of physiological synchrony in electrodermal activity (EDA) during a couple interaction task. A second objective was to compare the synchrony levels during a negative interaction condition versus a positive interaction condition. Finally, we analyzed the association between synchrony and self‐perception of empathy, dyadic empathy, and relationship satisfaction. Thirty‐two couples (64 individuals) participated in this study. Each couple performed a structured interaction task while the EDA of both partners was being registered. The quantification of synchrony was based on the cross‐correlation of both members' EDA time‐series. In order to control for coincidental synchrony, surrogate datasets were created by repeatedly shuffling the original data of spouses X and Y of a dyad and computing synchronies on the basis of the shuffled data (pseudosynchrony values). Our results confirmed the presence of significant EDA synchrony during the interaction. We also found that synchrony was higher during the negative interactions relative to the positive interactions. Additionally, physiological synchrony during positive interaction was higher for those couples in which males scored higher in dyadic empathy. The clinical implications of these findings are discussed.     

Individual differences and state effects on mind-wandering: Hypnotizability, dissociation, and sensory homogenization

Consciousness alterations can be experienced during unstructured, monotonous stimuli. These effects have not been linked to particular cognitive operations; individual differences in response to such stimulation remain poorly understood. We examined the role of hypnotizability and dissociative tendencies in mind-wandering (MW) during a sensory homogenization procedure (ganzfeld). We expected that the influence of ganzfeld on MW would be more pronounced among highly hypnotizable individuals (highs), particularly those high in dissociative tendencies. High and low hypnotizables, also stratified by dissociation, completed the sustained attention to response task during ganzfeld and control conditions. High dissociative highs made more commission errors during ganzfeld, suggesting increased MW, whereas the other groups displayed the opposite pattern. Increases in commission errors from the control condition to ganzfeld were associated with more alterations in consciousness and negative affect, but only among highs. Sensory homogenization had opposite effects on MW depending on the interaction of hypnotizability and dissociation.     

Dissociated control as a signature of typological variability in high hypnotic suggestibility

This study tested the prediction that dissociative tendencies modulate the impact of a hypnotic induction on cognitive control in different subtypes of highly suggestible individuals. Low suggestible (LS), low dissociative highly suggestible (LDHS), and high dissociative highly suggestible (HDHS) participants completed the Stroop color-naming task in control and hypnosis conditions. The magnitude of conflict adaptation (faster response times on incongruent trials preceded by an incongruent trial than those preceded by a congruent trial) was used as a measure of cognitive control. LS and LDHS participants displayed marginally superior up-regulation of cognitive control following a hypnotic induction, whereas HDHS participants’ performance declined. These findings indicate that dissociative tendencies modulate the influence of a hypnotic induction on cognitive control in high hypnotic suggestibility and suggest that HS individuals are comprised of distinct subtypes with dissimilar cognitive profiles.     

Unrepressed unconscious and unsaid in addictive symptomatology

The aim of this work is to understand, from a developmental-relational perspective, the emotional nature of addictive symptoms. Many studies have shown that addictions are linked to traumatic emotions that, once activated, could cause a feeling of emotional confusion that in the most severe cases could be connected to the fear that the Self might disintegrate. Before understanding the relationship between dissociation and addictions, it is essential to distinguish disintegration (désagrégation, in the language of Pierre Janet) and dissociation. Indeed, if the disintegration is a structural and pathological condition of the personality caused by early and chronic emotional traumatic memories, the dissociation is a defensive reaction to a stress: this reaction can be normal (flexible and adequate) or pathological (rigid and inadequate). Thus, addictive behaviours could be associated to a dissociative reaction in individuals with a structural dissociation of the personality (désagrégation). This disintegration would be linked to traumatic emotions: unconscious and unsymbolised emotions. On the unconscious nature of these emotions, the author of this paper underlines the role of the unrepressed unconscious, which in addicts would seem to be impaired.     

Pathological Dissociation and Its Relationships with Aggression and Delinquency in a College Student Sample in Hong Kong

Pathological dissociation is widely regarded as a cross-culturally occurring condition related to trauma and adversity and is an important construct in the mental health field. Yet, the frequency of pathological dissociation in both clinical and nonclinical populations in Hong Kong remains unknown. In addition, the relationship of pathological dissociation with aggression and delinquency requires further investigation. To investigate these relationships, we administered the Dissociative Experiences Scale-Taxon (DES-T), the 5-item Somatoform Dissociation Questionnaire (SDQ-5), selected sections from the Self-Report Version of the Dissociative Disorders Interview Schedule (SR-DDIS), the Reactive–Proactive Aggression Questionnaire (RPQ), and a delinquent behaviors checklist to 177 college students in Hong Kong. The findings suggest that pathological dissociation is not as rare as it is traditionally believed to be in Hong Kong. In our sample, 4.52% of the participants may have a DSM-5 dissociative disorder (including other specified dissociative disorder) while 9.60% met the DSM-5 diagnostic criteria for borderline personality disorder (BPD). Our findings indicate that the RPQ total score and delinquency may be more characteristic of BPD than of pathological dissociation. In addition, while reactive aggression was related to pathological dissociation and BPD symptoms in both genders, proactive aggression was related to pathological dissociation and BPD symptoms only in females. Although the findings of this study are preliminary and the results should be interpreted with caution, the study provides the first data regarding pathological dissociation and its relationship with aggression and delinquency in Hong Kong. Some implications for research and practice are highlighted. Further investigation of pathological dissociation in Hong Kong is necessary. In addition, more studies are essential to further examine the relationships between pathological dissociation, aggression, and delinquency in both clinical and nonclinical populations.     

Sex differences,activation level,and bilateral electrodermal activity

The effects of the activation level and subject’s sex on bilateral skin conductance measures were studied. Thirty right-handed subjects (15 males and 15 females) were exposed to three types of stimulus conditions: rest-period, verbal task and spatial task. Results showed that no relationship was observed between EDA asymmetry and the increase in the activation level induced by the verbal and the spatial tasks. Males showed both higher SCRs and greater frequency of responses on the left than on the right hand. The direction of electrodermal asymmetry remained constant regardless of the stimulus conditions. It was concluded that sex differences are important in the study of EDA asymmetry and that this asymmetry appeared to depend on peripheral variations.     

Acute dissociation after 1 night of sleep loss

Recent research has shown that dissociative symptoms are related to self-reports of deviant sleep experiences. The present study is the 1st to explore whether sleep loss can fuel dissociative symptoms. Twenty-five healthy volunteers were deprived of sleep for 1 night. Sleepiness and dissociative symptoms were assessed every 6 hr. The authors measured both spontaneous dissociative symptoms and dissociative symptoms induced by dot-staring during sensory deprivation. Sleepiness as well as spontaneous and induced dissociative symptoms were stable throughout the day but increased during the night. These findings provide further evidence for a robust relationship between disruptions in sleep patterns and dissociative symptoms.     

Autonomic physiological activity in mental rotation tasks

The electrodermal response (EDR) during a mental rotation (MR) task performance was investigated. For 6 males and 8 females (16-25 years old) there was a progressive increase in the number of EDRs as the angle of rotation (complexity) of the task was increased. These results support previous findings that autonomic physiological activity varies with the amount of information processing or its difficulty.     

The relationship between traumatic experiences, dissociation, and borderline personality pathology among male forensic patients and prisoners

In the present study the relationship between traumatic experiences, dissociation, and borderline personality disorder pathology is examined in a group of 39 male forensic patients and 192 male prisoners. Sexual and emotional abuse are significantly more common among forensic patients than among prisoners. Patients also report a broader range of different kinds of traumas. Prisoners report significantly more dissociative symptoms. Analyses of the relationship of type of trauma on the one hand and dissociation and borderline personality pathology on the other show that sexual abuse is significantly associated with borderline personality pathology but not with dissociation among the patients. In the prison sample these associations are found only for familial but not extrafamilial sexual abuse. When the subjects are grouped on account of presence or absence of a borderline personality disorder, highly significant differences on dissociation are found between both groups. The results from this study lend support to the hypothesis that sexual abuse is not related to dissociative symptoms but merely to borderline personality pathology. Because most subjects in this study are not patients, these findings are not likely to be confounded by false memories of traumatic events that are recovered by psychotherapy. Furthermore, dissociative symptoms are found to be related to borderline personality pathology and not to the experience of traumatic events.     

Experience-dependent alterations in conscious resting state activity following perceptuomotor learning

In monkeys and rats, neural activity patterns during learning are reactivated during subsequent periods of rest or sleep. According to the reactivation–consolidation account, this process underlies the consolidation of memories. Brain imaging studies have extended these findings to humans during sleep, but not yet, during rest. Here, we show that learning-related reactivation also occurs in humans during rest. During functional MRI-scanning, participants trained on a perceptuomotor task flanked by rest periods. During training, we found robust activity in the superior parietal cortex. During post-training rest, this same area reactivated. We also found a link between parietal reactivation and learning. Activity in superior parietal cortex was associated with learning during training, and a control group that did not train on the perceptuomotor task did not show any difference between the pre- and post-training rest blocks in this region. These findings indicate that, during rest, reactivation also occurs in humans. This process may contribute to consolidation of perceptuomotor memories.     

Evaluating the Safety and Effectiveness of the Weighted Blanket With Adults During an Inpatient Mental Health Hospitalization

The weighted blanket (WB) is a modality used to self-comfort, rest, sleep, and decrease anxiety. This exploratory, pilot study investigates the safety and effectiveness of the standardized use of the 30-pound WB with 30 adults during an acute inpatient mental health hospitalization. Safety measures include blood pressure, pulse rate, and pulse oximetry monitoring, with and without the 30-pound WB. The State Trait Anxiety Inventory-10 (STAI-10), a self-rating 0–10 anxiety scale, and electrodermal activity (EDA) readings measure effectiveness for anxiety reduction. No statistical differences in vital signs indicate WB safety. The STAI-10 and self-ratings indicate 60% had a significant reduction in anxiety using the WB. EDA readings were inconclusive.     

The driver vigilance telemetric control system (DVTCS): Investigating sensitivity to experimentally induced sleep loss and fatigue

Vigilance technologies are used in the Australian rail industry to address the risks associated with driver sleepiness and fatigue. The aim of this study was to investigate whether a new device, designed to detect lowered states of arousal using electrodermal activity (EDA), would be sensitive to experimentally induced sleepiness and fatigue. Fifteen individuals (7 of them female, 9 male; 18–32 years of age) spent 3 consecutive days in the laboratory, which included 1 night of sustained wakefulness (28 h). The participants completed a 10-min psychomotor vigilance task (PVT) and fatigue and sleepiness ratings every 2 h, and a 30-min driving simulator every 4 h. As was expected, simulated driving, PVT, and subjective ratings indicated increasing levels of sleepiness and fatigue during sustained wakefulness. The EDA device output did not coincide with these findings. The results indicated that the EDA indicator was not sensitive to increased sleepiness and fatigue at the levels produced in the present study.     

Stress regulation and cognitive control: evidence relating cortisol reactivity and neural responses to errors

In this study, we tested the relationship between error-related signals of cognitive control and cortisol reactivity, investigating the hypothesis of common systems for cognitive and emotional self-regulation. Eighty-three participants completed a Stroop task while electroencephalography (EEG) was recorded. Three error-related indices were derived from the EEG: the error-related negativity (ERN), error positivity (Pe), and error-related alpha suppression (ERAS). Pre- and posttask salivary samples were assayed for cortisol, and cortisol change scores were correlated with the EEG variables. Better error–correct differentiation in the ERN predicted less cortisol increase during the task, whereas greater ERAS predicted greater cortisol increase during the task; the Pe was not correlated with cortisol changes. We concluded that an enhanced ERN, part of an adaptive cognitive control system, predicts successful stress regulation. In contrast, an enhanced ERAS response may reflect error-related arousal that is not adaptive. The results support the concept of overlapping systems for cognitive and emotional self-regulation.     

Training on integrated versus separated Stroop tasks: The progression of interference and facilitation

Two experiments examined the course of interference and facilitation in the Stroop (1935) task during training. Two versions of the task were compared: integrated (e.g., the word RED in the color green) and separated (e.g., green asterisks above the word RED). Stimuli were congruent (RED in red), incongruent (GREEN in red), or neutral (XXX in red). Over 5-day (Experiment 1) and 10-day (Experiment 2) training sessions, facilitation due to congruence was small, stable, and equivalent in both task versions. In contrast, interference declined sharply on the integrated task over Days 1-3, then slowed to parallel the gradual decline on the separated task. Finally, training on the color naming task did not affect a word reading task administered after training. These findings imply that (a) Stroop interference initially reflects two problems—overcoming integration and managing two conflicting information sources; (b) with practice, the larger integration problem is solved relatively quickly, rendering the integrated and separated tasks quite comparable thereafter; and (c) facilitation and interference in the Stroop task may be independent. These results challenge extant theories of the Stroop effect, which do not predict such effects.     

Trauma as an objective or subjective experience: The association between types of traumatic events,personality traits,subjective experience of the event,and posttraumatic symptoms

The study aimed to examine the discrete effect of objective (type of trauma and demographic characteristics) and subjective (proximity to the trauma, subjective experience of the trauma as a threat, the Big Five personality traits, and dissociative symptoms) factors on the risk for PTSD among 1,210 undergraduate students. The findings indicate that survivors of physical/sexual assault scored the highest on proximity to the trauma, subjective experience of the trauma as a threat, neuroticism, dissociation, and PTSD symptoms. In addition, subjective experience of the trauma, proximity to it, type of trauma, dissociation, and neuroticism were associated with the risk for PTSD symptoms. The findings point to the significance of both subjective and objective variables in the risk for PTSD symptoms.