Pain response in depersonalization: a functional imaging study using hypnosis in healthy subjects

Effects of a dissociative drug on fronto-limbic resting-state functional connectivity in individuals with posttraumatic stress disorder: a randomized controlled pilot study

RATIONALE

A subanesthetic dose of ketamine, a non-competitive N-methyl-D-aspartate glutamate receptor (NMDAR) antagonist, elicits dissociation in individuals with posttraumatic stress disorder (PTSD), who also often suffer from chronic dissociative symptoms in daily life. These debilitating symptoms have not only been linked to worse PTSD trajectories, but also to increased resting-state functional connectivity (RSFC) between medial prefrontal cortex (mPFC) and amygdala, supporting the conceptualization of dissociation as emotion overmodulation. Yet, as studies were observational, causal evidence is lacking.

OBJECTIVES

The present randomized controlled pilot study examines the effect of ketamine, a dissociative drug, on RSFC between mPFC subregions and amygdala in individuals with PTSD.

METHODS

Twenty-six individuals with PTSD received either ketamine (0.5mg/kg; n = 12) or the control drug midazolam (0.045mg/kg; n = 14) during functional magnetic resonance imaging (fMRI). RSFC between amygdala and mPFC subregions, i.e., ventromedial PFC (vmPFC), dorsomedial PFC (dmPFC) and anterior-medial PFC (amPFC), was assessed at baseline and during intravenous drug infusion.

RESULTS

Contrary to pre-registered predictions, ketamine did not promote a greater increase in RSFC between amygdala and mPFC subregions from baseline to infusion compared to midazolam. Instead, ketamine elicited a stronger transient decrease in vmPFC-amygdala RSFC compared to midazolam.

CONCLUSIONS

A dissociative drug did not increase fronto-limbic RSFC in individuals with PTSD. These preliminary experimental findings contrast with prior correlative findings and call for further exploration and, potentially, a more differentiated view on the neurobiological underpinning of dissociative phenomena in PTSD.

Hypnotic suggestion versus sensory modulation of bodily awareness

Bodily awareness arises from somatosensory, vestibular, and visual inputs but cannot be reduced to these incoming sensory signals. Cognitive factors are known to also impact bodily awareness, though their specific influence is poorly understood. Here we systematically compared the effects of sensory (bottom-up) and cognitive (top-down) manipulations on the estimated size of body parts. Toward this end, in a repeated-measures design, we sought to induce the illusion that the right index finger was elongating by vibrating the biceps tendon of the left arm whilst participants grasped the tip of their right index finger (Lackner illusion; bottom-up) and separately by hypnotic suggestion (top-down), with a sham version of the Lackner illusion as an active control condition. The effects of these manipulations were assessed with perceptual and motor tasks to capture different components of the representation of body size. We found that hypnotic suggestion significantly induced the illusion in both tasks relative to the sham condition. The magnitudes of these effects were stronger than those in the Lackner illusion condition, which only produced a significantly stronger illusion than the sham condition in the perceptual task. We further observed that illusion magnitude significantly correlated across tasks and conditions, suggesting partly shared mechanisms. These results are in line with theories of separate but interacting representational processes for perception and action and highlight the influence of cognitive factors on low-level body representations.

Comparative effects of hypnotic suggestion and imagery instruction on bodily awareness

Bodily awareness is informed by both sensory data and prior knowledge. Although misleading sensory signals have been repeatedly shown to affect bodily awareness, only scant attention has been given to the influence of cognitive variables. Hypnotic suggestion has recently been shown to impact visuospatial and sensorimotor representations of body-part size although the mechanisms subserving this effect are yet to be identified. Mental imagery might play a causal or facilitative role in this effect, as it has been shown to influence body awareness in previous studies. Nonetheless, current views ascribe only an epiphenomenal role to imagery in the implementation of hypnotic suggestions. This study compared the effects of hypnotic suggestion and imagery instruction for influencing the visuospatial and sensorimotor aspects of body-size representation. Both experimental manipulations produced significant increases (elongation) in both representations compared to baseline, although the effects were larger in the hypnotic suggestion condition. The effects of both manipulations were highly correlated across participants, suggesting overlapping mechanisms. Self-reports suggested that the use of voluntary imagery did not significantly contribute to the efficacy of either manipulation. Rather, top-down effects on body representations seem to be partly driven by response expectancies, spontaneous imagery, and hypnotic suggestibility in both conditions. These results are in line with current theories of suggestion and raise fundamental questions regarding the mechanisms driving the influence of cognition on body representations.

A neurophenomenological approach to non-ordinary states of consciousness: hypnosis, meditation, and psychedelics

No contemporary unifying framework has been provided for the study of non-ordinary states of consciousness (NSCs) despite increased interest in hypnosis, meditation, and psychedelics. NSCs induce shifts in experiential contents (what appears to the experiencer) and/or structure (how it appears). This can allow the investigation of the plastic and dynamic nature of experience from a multiscale perspective that includes mind, brain, body, and context. We propose a neurophenomenological (NP) approach to the study of NSCs which highlights their role as catalysts of transformation in clinical practice by refining our understanding of the relationships between experiential (subjective) and neural dynamics. We outline the ethical implications of the NP approach for standard conceptions of health and pathology as well as the crucial role of experience-based know-how in NSC-related research and application.

Top-down effect of body representation on pain perception

Many studies on body representation intend to change the perceived size, material, and structure of the body. However, whether the perception of a stimulus can be modified by manipulating body representation remains largely unexplored. Thus, the current study investigated the relationship between transparency of body representation and pain perception. Using augmented reality technology, we made the participants' limbs transparent and analyzed changes in body representation. Using a questionnaire, we confirmed that the participants perceived their limb as transparent. Simultaneously, their sense of ownership of the limb decreased, because they felt that it no longer belonged to their body. The participants were given an electrical stimulus to assess their subjective perception of pain intensity. An increase in limb opacity decreased the perception of pain, which, in turn, increased the feeling of transparency. These results suggested that the feeling of transparency in their limb favored the decrease in perceived pain. This effect was modified by body ownership, where high levels reinforced the analgesic effect. However, body ownership displayed a positive relationship with perceived pain. The study suggests that body transparency may constitute a strategy for decreasing refractory pain given that body ownership is retained at a high level.

Symptoms of depersonalisation/derealisation disorder as measured by brain electrical activity: A systematic review

Depersonalisation/derealisation disorder (DPD) refers to frequent and persistent detachment from bodily self and disengagement from the outside world. As a dissociative disorder, DPD affects 1-2 % of the population, but takes 7-12 years on average to be accurately diagnosed. In this systematic review, we comprehensively describe research targeting the neural correlates of core DPD symptoms, covering publications between 1992 and 2020 that have used electrophysiological techniques. The aim was to investigate the diagnostic potential of these relatively inexpensive and convenient neuroimaging tools. We review the EEG power spectrum, components of the event-related potential (ERP), as well as vestibular and heartbeat evoked potentials as likely electrophysiological biomarkers to study DPD symptoms. We argue that acute anxiety- or trauma-related impairments in the integration of interoceptive and exteroceptive signals play a key role in the formation of DPD symptoms, and that future research needs analysis methods that can take this integration into account. We suggest tools for prospective studies of electrophysiological DPD biomarkers, which are urgently needed to fully develop their diagnostic potential.

The Dissociative Subtype of Post-traumatic Stress Disorder: Research Update on Clinical and Neurobiological Features

Recently, a dissociative subtype of post-traumatic stress disorder (PTSD) has been included in the DSM-5. This review focuses on the clinical and neurobiological features that distinguish the dissociative subtype of PTSD from non-dissociative PTSD. Clinically, the dissociative subtype of PTSD is associated with high PTSD severity, predominance of derealization and depersonalization symptoms, a more significant history of early life trauma, and higher levels of comorbid psychiatric disorders. Furthermore, PTSD patients with dissociative symptoms exhibit different psychophysiological and neural responses to the recall of traumatic memories. While individuals with non-dissociative PTSD exhibit an increased heart rate, decreased activation of prefrontal regions, and increased activation of the amygdala in response to traumatic reminders, individuals with the dissociative subtype of PTSD show an opposite pattern. It has been proposed that dissociation is a regulatory strategy to restrain extreme arousal in PTSD through hyperinhibition of limbic regions. In this research update, promises and pitfalls in current research studies on the dissociative subtype of PTSD are listed. Inclusion of the dissociative subtype of PTSD in the DSM-5 stimulates research on the prevalence, symptomatology, and neurobiology of the dissociative subtype of PTSD and poses a challenge to improve treatment outcome in PTSD patients with dissociative symptoms.

THE NEUROPHENOMENOLOGY OF OUT-OF-BODY EXPERIENCES INDUCED BY HYPNOTIC SUGGESTIONS

Inducing out-of-body experiences in hypnosis (H-OBEs) offers an almost unique opportunity to investigate them under controlled conditions. OBEs were induced as an imaginative task in a resting condition (I-OBE) or in hypnosis (H-OBE) in a group of 15 high hypnotizable subjects. A 32-channel EEG was recorded, and the spectral power and imaginary coherence of each frequency band and each couple of electrodes were calculated. At the end of each session, the Phenomenology of Consciousness Inventory (PCI) was administered to assess the phenomenological aspects of the subjects' experience. Significantly higher scores in the altered state, positive affect altered experience, and attention subdimensions of the PCI were reported in H-OBE than in I-OBE, which were associated with a significant decrease of power in beta and gamma band activity in right parieto-temporal derivations. These results suggest that the H-OBE may offer a useful experimental model of spontaneous OBEs.

Brain Activity and Functional Connectivity Associated with Hypnosis

Hypnosis has proven clinical utility, yet changes in brain activity underlying the hypnotic state have not yet been fully identified. Previous research suggests that hypnosis is associated with decreased default mode network (DMN) activity and that high hypnotizability is associated with greater functional connectivity between the executive control network (ECN) and the salience network (SN). We used functional magnetic resonance imaging to investigate activity and functional connectivity among these three networks in hypnosis. We selected 57 of 545 healthy subjects with very high or low hypnotizability using two hypnotizability scales. All subjects underwent four conditions in the scanner: rest, memory retrieval, and two different hypnosis experiences guided by standard pre-recorded instructions in counterbalanced order. Seeds for the ECN, SN, and DMN were left and right dorsolateral prefrontal cortex, dorsal anterior cingulate cortex (dACC), and posterior cingulate cortex (PCC), respectively. During hypnosis there was reduced activity in the dACC, increased functional connectivity between the dorsolateral prefrontal cortex (DLPFC;ECN) and the insula in the SN, and reduced connectivity between the ECN (DLPFC) and the DMN (PCC). These changes in neural activity underlie the focused attention, enhanced somatic and emotional control, and lack of self-consciousness that characterizes hypnosis.

The Odyssey of Dental Anxiety: From Prehistory to the Present. A Narrative Review

Dental anxiety (DA) can be considered as a universal phenomenon with a high prevalence worldwide; DA and pain are also the main causes for medical emergencies in the dental office, so their prevention is an essential part of patient safety and overall quality of care. Being DA and its consequences closely related to the fight-or-flight reaction, it seems reasonable to argue that the odyssey of DA began way back in the distant past, and has since probably evolved in parallel with the development of fight-or-flight reactions, implicit memory and knowledge, and ultimately consciousness. Basic emotions are related to survival functions in an inseparable psychosomatic unity that enable an immediate response to critical situations rather than generating knowledge, which is why many anxious patients are unaware of the cause of their anxiety. Archeological findings suggest that humans have been surprisingly skillful and knowledgeable since prehistory. Neanderthals used medicinal plants; and relics of dental tools bear witness to a kind of Neolithic proto-dentistry. In the two millennia BC, Egyptian and Greek physicians used both plants (such as papaver somniferum) and incubation (a forerunner of modern hypnosis, e.g., in the sleep temples dedicated to Asclepius) in the attempt to provide some form of therapy and painless surgery, whereas modern scientific medicine strongly understated the role of subjectivity and mind-body approaches until recently. DA has a wide range of causes and its management is far from being a matter of identifying the ideal sedative drug. A patient's proper management must include assessing his/her dental anxiety, ensuring good communications, and providing information (iatrosedation), effective local anesthesia, hypnosis, and/or a wise use of sedative drugs where necessary. Any weak link in this chain can cause avoidable suffering, mistrust, and emergencies, as well as having lifelong psychological consequences. Iatrosedation and hypnosis are no less relevant than drugs and should be considered as primary tools for the management of DA. Unlike pharmacological sedation, they allow to help patients cope with the dental procedure and also overcome their anxiety: achieving the latter may enable them to face future dental care autonomously, whereas pharmacological sedation can only afford a transient respite.

The use of Eriksonian Hypnosis to improve patient outcomes in pharmacy practice: A novel communication skill for pharmacists

Motivational Interviewing, pharmacist-based health coaching and traditional patient counseling techniques all show merit in improving communication between patients and health care providers. However, in order to effectively utilize these techniques one should have the ability to draw upon internal cognitive and psychological resources. Some patients have difficulty obtaining optimal health outcomes due to an unconscious inability to learn and connect with psychological resources. When this is the case, other methods of communication may need to be considered. With the appropriate training, Eriksonian Hypnosis or the use of techniques such as hypnotic language patterns (HLP) have the potential to be implemented into pharmacy practice settings and assist those patients who have previously failed to make positive behavior changes and act upon their health issues.

Concussion/mild traumatic brain injury-related chronic pain in males and females: A diagnostic modelling study

Pain is an unpleasant, complex, and perceived experience that places a significant burden on patients and clinicians. Its severity may be mediated by emotion, attitude, and environmental influences, and pain may be expressed differently in males and females. Traumatic brain injury (TBI) is frequently associated with chronic pain. This diagnostic modeling study examined sex differences in the construct of chronic pain in patients with delayed recovery from concussion/mild traumatic brain injury (mTBI).Data were collected from standardized questionnaires, neuroimaging records, and comprehensive clinical assessments. Bivariate associations were calculated using the Spearman correlation coefficient or analysis of variance. We established sex-specific stepwise multivariate linear regression models of factors associated with pain.Of the 94 participants diagnosed with mTBI (the mean age was 45.20 ± 9.94 years; 61.2% were males; the median time since injury was 197 days [interquartile range 139-416]), head/neck, and bodily pain were reported by 93% and 64%, respectively. No sex differences were identified in pain frequencies or severity. Pain was significantly associated with certain socio-demographic, injury-related, behavioral, and clinical variables. In the multivariable regression analysis, several determinants explained 60% of the pain variance in males and 46% in females.Pain is common in patients with delayed recovery from mTBI and is significantly associated with potentially modifiable clinical and nonclinical variables. Examining the multidimensional construct of pain in concussion/mTBI through a sex lens garners new directions for future longitudinal research on the pain mechanisms involved in postconcussion syndrome.

Hypnosis and imaging of the living human brain

Over more than two decades, studies using imaging techniques of the living human brain have begun to explore the neural correlates of hypnosis. The collective findings provide a gripping, albeit preliminary, account of the underlying neurobiological mechanisms involved in hypnotic phenomena. While substantial advances lend support to different hypotheses pertaining to hypnotic modulation of attention, control, and monitoring processes, the complex interactions among the many mediating variables largely hinder our ability to isolate robust commonalities across studies. The present account presents a critical integrative synthesis of neuroimaging studies targeting hypnosis as a function of suggestion. Specifically, hypnotic induction without task-specific suggestion is examined, as well as suggestions concerning sensation and perception, memory, and ideomotor response. The importance of carefully designed experiments is highlighted to better tease apart the neural correlates that subserve hypnotic phenomena. Moreover, converging findings intimate that hypnotic suggestions seem to induce specific neural patterns. These observations propose that suggestions may have the ability to target focal brain networks. Drawing on evidence spanning several technological modalities, neuroimaging studies of hypnosis pave the road to a more scientific understanding of a dramatic, yet largely evasive, domain of human behavior.

Pain perception and hypnosis: findings from recent functional neuroimaging studies

Hypnosis modulates pain perception and tolerance by affecting cortical and subcortical activity in brain regions involved in these processes. By reviewing functional neuroimaging studies focusing on pain perception under hypnosis, the authors aimed to identify brain activation-deactivation patterns occurring in hypnosis-modulated pain conditions. Different changes in brain functionality occurred throughout all components of the pain network and other brain areas. The anterior cingulate cortex appears to be central in modulating pain circuitry activity under hypnosis. Most studies also showed that the neural functions of the prefrontal, insular, and somatosensory cortices are consistently modified during hypnosis-modulated pain conditions. Functional neuroimaging studies support the clinical use of hypnosis in the management of pain conditions.

Neurophysiological correlates of dissociative symptoms

OBJECTIVE

Dissociation is a mental process with psychological and somatoform manifestations, which is closely related to hypnotic suggestibility and essentially shows the ability to obtain distance from reality. An increased tendency to dissociate is a frequently reported characteristic of patients with functional neurological symptoms and syndromes (FNSS), which account for a substantial part of all neurological admissions. This review aims to investigate what heart rate variability (HRV), EEG and neuroimaging data (MRI) reveal about the nature of dissociation and related conditions.

METHODS

Studies reporting HRV, EEG and neuroimaging data related to hypnosis, dissociation and FNSS were identified by searching the electronic databases Pubmed and ScienceDirect.

RESULTS

The majority of the identified studies concerned the physiological characteristics of hypnosis; relatively few investigations on dissociation related FNSS were identified. General findings were increased parasympathetic functioning during hypnosis (as measured by HRV), and lower HRV in patients with FNSS. The large variety of EEG and functional MRI investigations with diverse results challenges definite conclusions, but evidence suggests that subcortical as well as (pre)frontal regions serve emotion regulation in dissociative conditions. Functional connectivity analyses suggest the presence of altered brain networks in patients with FNSS, in which limbic areas have an increased influence on motor preparatory regions.

CONCLUSIONS

HRV, EEG and (functional) MRI are sensitive methods to detect physiological changes related to dissociation and dissociative disorders such as FNSS, and can possibly provide more information about their aetiology. The use of such measures could eventually provide biomarkers for earlier identification of patients at risk and appropriate treatment of dissociative conditions.

Method for simultaneous fMRI/EEG data collection during a focused attention suggestion for differential thermal sensation

In the present work, we demonstrate a method for concurrent collection of EEG/fMRI data. In our setup, EEG data are collected using a high-density 256-channel sensor net. The EEG amplifier itself is contained in a field isolation containment system (FICS), and MRI clock signals are synchronized with EEG data collection for subsequent MR artifact characterization and removal. We demonstrate this method first for resting state data collection. Thereafter, we demonstrate a protocol for EEG/fMRI data recording, while subjects listen to a tape asking them to visualize that their left hand is immersed in a cold-water bath and referred to, here, as the cold glove paradigm. Thermal differentials between each hand are measured throughout EEG/fMRI data collection using an MR compatible temperature sensor that we developed for this purpose. We collect cold glove EEG/fMRI data along with simultaneous differential hand temperature measurements both before and after hypnotic induction. Between pre and post sessions, single modality EEG data are collected during the hypnotic induction and depth assessment process. Our representative results demonstrate that significant changes in the EEG power spectrum can be measured during hypnotic induction, and that hand temperature changes during the cold glove paradigm can be detected rapidly using our MR compatible differential thermometry device.

Neurophysiology of hypnosis

We here review behavioral, neuroimaging and electrophysiological studies of hypnosis as a state, as well as hypnosis as a tool to modulate brain responses to painful stimulations. Studies have shown that hypnotic processes modify internal (self awareness) as well as external (environmental awareness) brain networks. Brain mechanisms underlying the modulation of pain perception under hypnotic conditions involve cortical as well as subcortical areas including anterior cingulate and prefrontal cortices, basal ganglia and thalami. Combined with local anesthesia and conscious sedation in patients undergoing surgery, hypnosis is associated with improved peri- and postoperative comfort of patients and surgeons. Finally, hypnosis can be considered as a useful analogue for simulating conversion and dissociation symptoms in healthy subjects, permitting better characterization of these challenging disorders by producing clinically similar experiences.

Gray matter volume alterations related to trait dissociation in PTSD and traumatized controls

OBJECTIVE

This study used voxel-based morphometry (VBM) to investigate brain structural alterations related to trait dissociation and its relationship with post-traumatic stress disorder (PTSD).

METHOD

Thirty-two subjects either developing (N = 15) or non-developing (N = 17) PTSD underwent MRI scanning and were assessed with the Dissociative Experience Scale (DES), subscales for pathological (DES-T) and non-pathological trait (DES-A) dissociation, and other clinical measures. Gray matter volume (GMV) was analyzed using VBM as implemented in SPM. PTSD and non-PTSD subjects were compared to assess brain alterations related to PTSD pathology, whereas correlation analyses between dissociation measures and GMV were performed on the whole sample (N = 32), irrespective of PTSD diagnosis, to identify alterations related to trait dissociation.

RESULTS

As compared to traumatized controls, PTSD subjects showed reduced GMV in the prefrontal cortex, hippocampus and lingual gyrus. Correlations with dissociation measures (DES, DES-T, and DES-A) consistently showed increased GMV in the medial and lateral prefrontal, orbitofrontal, parahippocampal, temporal polar, and inferior parietal cortices.

CONCLUSION

PTSD and dissociation seem to be associated with opposite volumetric patterns in the prefrontal cortex. Trait dissociation appears to involve increased GMV in prefrontal, paralimbic, and parietal cortices, with negligible differences between pathological and non-pathological dissociation.

Depersonalization experiences are strongly associated with dizziness and vertigo symptoms leading to increased health care consumption in the German general population

This study investigated the association of depersonalization (DP) experiences with dizziness and its impact on subjective impairment and health care use. Trained interviewers surveyed a representative sample of 1287 persons using standardized self-rating questionnaires on dizziness, DP, and mental distress. Symptoms of dizziness were reported by 15.8% (n = 201). Thereof, 62.7% endorsed at least one symptom of DP, 40% reported impairment by symptoms of DP, and 8.5% reported clinically significant DP. Regression analyses identified DP as a significant, independent predictor for dizziness symptom severity, health care use, and impairment by dizziness. With regard to the Vertigo Symptom Scale, DP explained 34.1% (p < 0.001) of the variance for severity of symptoms of dysfunction in the balance system. In conclusion, symptoms of DP, highly prevalent in patients complaining of dizziness and vertigo, were independently associated with increased impairment and health care use. The presence of DP symptoms should actively be explored in patients complaining of dizziness.

Frequency-dependent patterns of somatosensory cortical responses to vibrotactile stimulation in humans: a fMRI study

In the human mechanosensation system, rapidly adapting afferents project sensory signals of flutter (5-50Hz) to the contralateral primary somatosensory cortex (S1) and bilateral secondary somatosensory cortex (S2) whereas Pacinian afferents project sensory signals of vibration (50-400Hz) to bilateral S2. However, it remains largely unknown how somatosensory cortical activity changes as a function of vibrotactile frequency. This functional magnetic resonance imaging (fMRI) study investigated frequency dependency of somatosensory cortical activity in humans by applying vibrotactile stimulation with various frequencies (20-200Hz) to the index finger. We found more frequency-dependent voxels in the upper bank of the lateral sulcus (LS) of S2 than in S1 and the posterior parietal cortex of S2. Our statistical spatial clustering analysis showed that two groups of positively or negatively frequency-dependent voxels formed distinct clusters, most clearly in the LS. Using a cortical separability index, we reaffirmed that somatosensory cortical activity was most separable at 50Hz, previously known to demarcate flutter and vibration. Our results suggest that the LS (S2) may play an important role in processing vibrotactile frequency information and that the somatosensory cortex may include spatially localized neural assemblies specialized to higher or lower vibrotactile frequency.

Borderline personality disorder and depression: an update

To review the literature related to recent temperamental and biological findings on borderline personality disorder (BPD) and major depression, the close link between the two disorders, and the latest therapeutical findings on BPD, focusing on the conditions of co-morbidity between depression and BPD. The National Institutes of Health's PubMed database was used to identify indexed studies on BPD, depression and the co-morbidity between the two. Only studies published between 2000 and 2011 were assessed. Similar temperamental features have been demonstrated in BPD and depression. The strong link between the two disorders seems to be widely recognized by scientific community. Psychotherapy and new antipsychotics are the topics of current major interest of research. The therapeutic targets in the case of co-morbidity are BPD features associated with depressive symptoms, thus influencing prognosis. A global assessment is, in fact, fundamental for a successful therapy for the treatment of the several aspects of a complex psychopathological phenomenon.

The dissociative subtype of posttraumatic stress disorder: rationale, clinical and neurobiological evidence, and implications

BACKGROUND

Clinical and neurobiological evidence for a dissociative subtype of posttraumatic stress disorder (PTSD) has recently been documented. A dissociative subtype of PTSD is being considered for inclusion in the forthcoming Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5) to address the symptoms of depersonalization and derealization found among a subset of patients with PTSD. This article reviews research related to the dissociative subtype including antecedent, concurrent, and predictive validators as well as the rationale for recommending the dissociative subtype.

METHODS

The relevant literature pertaining to the dissociative subtype of PTSD was reviewed.

RESULTS

Latent class analyses point toward a specific subtype of PTSD consisting of symptoms of depersonalization and derealization in both veteran and civilian samples of PTSD. Compared to individuals with PTSD, those with the dissociative subtype of PTSD also exhibit a different pattern of neurobiological response to symptom provocation as well as a differential response to current cognitive behavioral treatment designed for PTSD.

CONCLUSIONS

We recommend that consideration be given to adding a dissociative subtype of PTSD in the revision of the DSM. This facilitates more accurate analysis of different phenotypes of PTSD, assist in treatment planning that is informed by considering the degree of patients' dissociativity, will improve treatment outcome, and will lead to much-needed research about the prevalence, symptomatology, neurobiology, and treatment of individuals with the dissociative subtype of PTSD.

Where are we going? An update on assessment, treatment, and neurobiological research in dissociative disorders as we move toward the DSM-5

This article provides an overview of the process of developing the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) of the American Psychiatric Association with a focus on issues related to the trauma-related disorders, particularly the dissociative disorders (DD). We also discuss the highlights of research within the past 5 years in the assessment, treatment, and neurobiological basis of trauma disorders. Recent research shows that DD are associated with severe symptoms as well as a higher rate of utilization of mental health treatment compared with other psychiatric disorders. As a result, DD, like other complex posttraumatic disorders, exact a high economic as well as personal burden for patients and society. The latest research indicates that DD patients show a suboptimal response to standard exposure-based treatments for posttraumatic stress disorder as well as high levels of attrition from treatment. An emerging body of research on DD treatment, primarily of naturalistic and open trials, indicates that patients who receive specialized treatment that addresses their trauma-based, dissociative symptoms show improved functioning and reduced symptoms. Recent studies of the underlying neurobiological basis for dissociation support a model of excessive limbic inhibition in DD that is consistent with the phenomenology and clinical presentation of these patients. We are optimistic that the forthcoming DSM-5 will stimulate research on dissociation and the DD and suggest areas for future studies.

Posthypnotic state changes and flashbacks: analogous processes?

Careful study of the posttraumatic stress disorder and hypnosis literatures reveals some parallels between posttraumatic flashbacks and responses to posthypnotic suggestions. Highly susceptible subjects can slip into hypnosis spontaneously and accept and respond to implied or inadvertent suggestions, some of which may operate in a manner equivalent to posthypnotic suggestions. Later, exposure to appropriate cues may trigger an intrusive revivification of the hypnotic state in which the suggestion occurred. This sequence of events closely resembles the sequence of reactions that some individuals have to trauma that ultimately leads to flashbacks. Thus, flashbacks may be conceived of as intrusive posttraumatic revivifications of trauma-induced hypnosis-like states that are reactivated by trauma-reminiscent cues operating similarly to posthypnotic signals. Implications of viewing flashbacks in this way, especially if this view is supported by future research, could include significant changes in how posttraumatic stress disorder is conceptualized and treated.

Effects of hypnotic focused analgesia on dental pain threshold

The rate, intensity, and selectivity of hypnotic focused analgesia (HFA) were tested with dental pulp stimulation. Thirty-one healthy subjects were hypnotized, and hypnotic suggestions were given for anesthesia of the right mandibular arch. A posthypnotic suggestion of persisting analgesia was also given. The pain threshold of the first premolar was bilaterally measured before, during, and after hypnosis using a pulp tester. During hypnosis, the pain threshold increased significantly (p < .0001) for both sides. The posthypnotic right pain threshold was also significantly (p < .0015) higher than in the basal condition.

Modular networks involving the medial frontal cortex: towards the development of neuropsychiatry

OBJECTIVES

The pathophysiology of mental disorders is largely unresolved. We propose that the identification of abnormalities in brain modular networks will provide a promising approach for the understanding of mental disorders.

METHODS

We review the current discussion on the neuroscientific basis of psychiatric diseases and review recent studies in functional neuroimaging and systems physiology on mental functions of the human brain.

RESULTS

We propose that brain functional units are organized in modular networks. Modular networks allow for flexibility within the modular processing units and across interconnected modules affording optimization of task performance and deficit compensation in disease. As an example it will be shown that differentiated modules in medial frontal cortex play a critical role for the control of behaviour. This will be contrasted to recent studies in neurological and psychiatric patients revealing behavioural abnormalities due to lesions or reversibly deprived functions in the medial frontal cortex.

CONCLUSIONS

These findings are conceptualized as starting points for a neuroscience based diagnosis and treatment of brain diseases at the border of psychiatry and neurology.

Effects of trauma-related cues on pain processing in posttraumatic stress disorder: an fMRI investigation

BACKGROUND

Imaging studies of pain processing in primary psychiatric disorders are just emerging. This study explored the neural correlates of stress-induced analgesia in individuals with posttraumatic stress disorder (PTSD). It combined functional magnetic resonance imaging (fMRI) and the traumatic script-driven imagery symptom provocation paradigm to examine the effects of trauma-related cues on pain perception in individuals with PTSD.

METHODS

The study included 17 patients with PTSD and 26 healthy, trauma-exposed controls. Participants received warm (nonpainful) or hot (painful) thermal stimuli after listening to a neutral or a traumatic script while they were undergoing an fMRI scan at a 4.0 T field strength.

RESULTS

Between-group analyses revealed that after exposure to the traumatic scripts, the blood oxygen level-dependent (BOLD) signal during pain perception was greater in the PTSD group than the control group in the head of the caudate. In the PTSD group, strong positive correlations resulted between BOLD signal and symptom severity in a number of brain regions previously implicated in stress-induced analgesia, such as the thalamus and the head of the caudate nucleus. Trait dissociation as measured by the Dissociative Experiences Scale correlated negatively with the right amygdala and the left putamen.

LIMITATIONS

This study included heterogeneous traumatic experiences, a different proportion of military trauma in the PTSD versus the control group and medicated patients with PTSD.

CONCLUSION

These data indicate that in patients with PTSD trauma recall will lead in a state-dependent manner to greater activation in brain regions implicated in stress-induced analgesia. Correlational analyses lend support to cortical hyperinhibition of the amygdala as a function of dissociation.

Emotion modulation in PTSD: Clinical and neurobiological evidence for a dissociative subtype

In this article, the authors present evidence regarding a dissociative subtype of PTSD, with clinical and neurobiological features that can be distinguished from nondissociative PTSD. The dissociative subtype is characterized by overmodulation of affect, while the more common undermodulated type involves the predominance of reexperiencing and hyperarousal symptoms. This article focuses on the neural manifestations of the dissociative subtype in PTSD and compares it to those underlying the reexperiencing/hyperaroused subtype. A model that includes these two types of emotion dysregulation in PTSD is described. In this model, reexperiencing/hyperarousal reactivity is viewed as a form of emotion dysregulation that involves emotional undermodulation, mediated by failure of prefrontal inhibition of limbic regions. In contrast, the dissociative subtype of PTSD is described as a form of emotion dysregulation that involves emotional overmodulation mediated by midline prefrontal inhibition of the same limbic regions. Both types of modulation are involved in a dynamic interplay and lead to alternating symptom profiles in PTSD. These findings have important implications for treatment of PTSD, including the need to assess patients with PTSD for dissociative symptoms and to incorporate the treatment of dissociative symptoms into stage-oriented trauma treatment.

Pain sensitivity and neural processing during dissociative states in patients with borderline personality disorder with and without comorbid posttraumatic stress disorder: a pilot study

BACKGROUND

Stress-induced dissociative states involving analgesia are a common feature of borderline personality disorder (BPD) and posttraumatic stress disorder (PTSD). Our aim was to investigate the psychologic, somatosensory (pain sensitivity) and neural correlates of dissociative states in patients with these disorders.

METHODS

We included 15 women with BPD who were not taking medication; 10 of these women had comorbid PTSD. While undergoing functional magnetic resonance imaging at 1.5 Tesla, participants were exposed to a script describing a personalized dissociation-inducing situation and a personalized script describing a neutral situation. We assessed dissociative psychopathology and pain sensitivity.

RESULTS

Dissociative psychopathology scores were significantly higher and pain sensitivity was lower after the dissociation-inducing script was read compared with the neutral script. The blood oxygen level-dependent (BOLD) signal was significantly increased in the left inferior frontal gyrus (Brodmann area [BA] 9) during the presentation of the dissociation-inducing script. Regression analyses revealed positive correlations between BOLD signal and dissociative psychopathology in the left superior frontal gyrus (BA 6) and negative correlations in the right middle (BA 21) and inferior temporal gyrus (BA 20). In the subgroup of participants with comorbid PTSD, we also found increased activity in the left cingulate gyrus (BA 32) during script-driven imagery-induced dissociation, a positive correlation between dissociation scores and activity in the right and left insula (BA 13) and a negative correlation in the right parahippocampal gyrus (BA 35).

LIMITATIONS

The main limitation of this pilot study is the absence of a control group. Therefore, the results may also reflect the neural correlates of non-BPD/PTSD specific dissociative states or the neural correlates of emotionally stressful or "loaded" memories. Another limitation is the uncorrected statistical level of the functional magnetic resonance imaging results.

CONCLUSION

Our results showed that the script-driven imagery method is capable of inducing dissociative states in participants with BPD with and without comorbid PTSD. These states were characterized by reduced pain sensitivity and a frontolimbic activation pattern, which resembles the findings in participants with PTSD while in dissociative states.

Depersonalization disorder

PURPOSE OF REVIEW

There is increasing interest in depersonalization disorder, in part because of the increased community awareness of the condition via the Internet. The disorder may be more prevalent than schizophrenia but is often misdiagnosed; hence, an update is timely.

RECENT FINDINGS

Recent research has included characterization of the nosology and phenomenology of the disorder, whereas emerging evidence demonstrates a neurophysiological dampening down in addition to psychological dampening in the face of emotional stimulation.

SUMMARY

Greater understanding of the clinical characteristics of this disorder will improve the reliability of diagnosis and aid the development of neurobiological and psychological models for empirical testing. Although response to current treatments has been disappointing, recent research has identified the basis for the development of new pharmacological and psychological treatments.

The latest neuroimaging findings in borderline personality disorder

This review provides an overview of the most recent neuroimaging findings in borderline personality disorder. The contributions of the structural and functional imaging studies of the past 3 years are presented to help us better understand this severe psychiatric disorder. There are three domains of functional imaging findings: 1) affective dysregulation; 2) the complex of dissociation, self-injurious behavior, and pain processing; and 3) social interaction. Knowledge of the neurobiological basis of borderline personality disorder has grown considerably. Therefore, these findings convey a good impression of the current findings from neuroimaging research in this disorder and also of the necessary next steps with regard to content and methodology.

Neuroimaging in psychiatry: from bench to bedside

This perspective considers the present and the future role of different neuroimaging techniques in the field of psychiatry. After identifying shortcomings of the mainly symptom-focussed diagnostic processes and treatment decisions in modern psychiatry, we suggest topics where neuroimaging methods have the potential to help. These include better understanding of the pathophysiology, improved diagnoses, assistance in therapeutic decisions and the supervision of treatment success by direct assessment of improvement in disease-related brain functions. These different questions are illustrated by examples from neuroimaging studies, with a focus on severe mental and neuropsychiatric illnesses such as schizophrenia and depression. Despite all reservations addressed in the article, we are optimistic that neuroimaging has a huge potential with regard to the above-mentioned questions. We expect that neuroimaging will play an increasing role in the future refinement of the diagnostic process and aid in the development of new therapies in the field of psychiatry.

Cognitive-affective neuroscience of depersonalization

Depersonalization disorder (DPD) is characterized by a subjective sense of detachment from one's own being and a sense of unreality. An examination of the psychobiology of depersonalization symptoms may be useful in understanding the cognitive-affective neuroscience of embodiment. DPD may be mediated by neurocircuitry and neurotransmitters involved in the integration of sensory processing and of the body schema, and in the mediation of emotional experience and the identification of feelings. For example, DPD has been found to involve autonomic blunting, deactivation of sub-cortical structures, and disturbances in molecular systems in such circuitry. An evolutionary perspective suggests that attenuation of emotional responses, mediated by deactivation of limbic structures, may sometimes be advantageous in response to inescapable stress.

[Depersonalisation/derealization - clinical picture, diagnostics and therapy]

The present state of knowledge about depersonalization (DP) and derealization (DR) is reviewed with respect to classification, epidemiology, etiology, and therapy. Mild and transient DP-DR are considered to be common phenomena. The prevalence of depersonalization-derealization disorder (DP-DR-D) is estimated to be approx. 1-2% of the general population in the Western hemisphere. DP-DR-D is probably severely underdiagnosed. DP-DR-D is strongly associated with depression and anxiety disorders. It is suggested that symptoms of DP-DR indicate disease severity and negatively predict therapy outcome. Neurobiological and psychological models have shown that a disordered body schema and emotional and autonomic blunting are essential components of the disorder. Despite the frequency of DPDR and its clinical relevance, there is a considerable lack of empirical research on DP-DR with respect to the health-care situation of depersonalized patients and with regard to treatment options.

Brain imaging and psychotherapy: methodological considerations and practical implications

The development of psychotherapy has been based on psychological theories and clinical effects. However, an investigation of the neurobiological mechanisms of psychological interventions is also needed in order to improve indication and prognosis, inform the choice of parallel pharmacotherapy, provide outcome measures and potentially even aid the development of new treatment protocols. This neurobiological investigation can be informed by animal models, for example of learning and conditioning, but will essentially need the non-invasive techniques of functional neuroimaging in order to assess psychotherapy effects on patients' brains, which will be reviewed here. Most research so far has been conducted in obsessive compulsive disorder (OCD), anxiety disorders and depression. Effects in OCD were particularly exciting in that both cognitive behavioural therapy and medication with a selective serotonin inhibitor led to a reduction in blood flow in the caudate nucleus. In phobia, brief courses of behavioural therapy produced marked reductions of paralimbic responses to offensive stimuli in line with the clinical improvement. Findings in depression are less consistent, with both increases and decreases in prefrontal metabolism being reported. However, they are important in pointing to different mechanisms for the clinical effects of pharmacotherapy (more "bottom up") and psychotherapy (more "top down"). For the future it would be desirable if the findings of psychotherapy changes to brain activation patterns were confirmed in larger groups with homogenous imaging protocols. Functional imaging has already made great contributions to the understanding of the neural correlates of psychopathology. For example, evidence converges to suggest that the subgenual cingulate is crucial for mood regulation. One current clinical application of these findings is deep brain stimulation in areas highlighted by such imaging studies. I will discuss their initial application in depression and OCD, and suggest potential alternative options based on recent developments in neurofeedback technology.

Depersonalization disorder: pharmacological approaches

Depersonalization disorder (DPD) is a chronic and distressing condition with a prevalence in the general population between 0.8 and 2%. Several neurobiological studies in the last decade have shown that patients have suppressed limbic activation to emotional stimuli. Such findings are in line with a model which suggests that the condition is generated by an anxiety-triggered, 'hard-wired' inhibitory response to threat. Such a mechanism would ensure the preservation of adaptive behavior, during situations normally associated with overwhelming and potentially disorganizing anxiety. In DPD, such a response would become chronic and dysfunctional. Depersonalization remains a condition for which no definitive treatment exists, and for which conventional medications, such as antidepressants or antipsychotics, have been found to be of little value. Fortunately, a few promising lines of pharmacological treatment have emerged in recent years, although more rigorous studies are needed. For example, a number of studies suggest that opioid receptor antagonists such as naltrexone and naloxone are useful in at least a subgroup of patients. In spite of initial expectations, the use of lamotrigine as a sole medication has not been found useful. However, open-label trials suggest that its use as an add-on treatment with selective serotonin reuptake inhibitors (SSRIs) is beneficial in a substantial number of patients. Similarly, the use of clonazepam, particularly in conjunction with SSRI antidepressants, appears to be beneficial in patients with high levels of background anxiety. In line with the stress-related model of depersonalization, those neurotransmitter systems of relevance to depersonalization are known to play important inhibitory roles in the regulation of the stress response.