Physical and social pains in borderline disorder and neuroanatomical correlates: a systematic review

Proposition of Two Subtypes of Patients at Risk of Suicide: Pain Hypersensitive Vs. Dissociative

PURPOSE OF REVIEW

The pain-suicide relationship is one of the most debated in recent literature, but theories and clinical evidence have often reached contrasting conclusions. Through a critical overview of theoretical, meta-analytical and empirical contributions, we aimed at advancing the conversation on the pain-suicide relationship by integrating research on related concepts, specifically inflammation and dissociation, and their effects on interoceptive processes and pain perception.

RECENT FINDINGS

Ideation-to-action theories consider increased pain tolerance a key risk factor for the transition from suicidal ideation to attempt. However, several meta-analytical findings suggest that suicidal thoughts and behaviors are associated with inflammation-induced pain sensitization. On the one hand, inflammation contributes to the development and maintenance of chronic pain conditions and mood disorders, and is associated with interoceptive hypervigilance and pain hypersensitivity. Moreover, a trait of increased pain tolerance does not seem to distinguish the individuals attempting suicide among those living with suicidal thoughts. On the other, temporary hypoalgesia is often activated by dissociative experiences. Highly dissociative individuals can indeed be exposed to frequent disintegration of interoceptive processes and transitory hyposensitivity to pain. In light of this, two different patterns of responses to stress (i.e. inflammation vs. dissociation) may characterize different kinds of patients at risk of suicide, associated with specific patterns of interoceptive functioning, pain sensitivity and possibly suicidal ideation. This proposition is partially supported by neuroimaging studies on post-traumatic stress disorder and psychodynamic perspectives on neurodevelopment, as well as alternative clustering models of suicidal behavior. Theoretical, meta-analytical and neurobiological evidence highlight two opposite directions in the pain-suicide relationship: hyper- vs. hyposensitivity. Such contrasts may be explained by the existence of two tendencies in stress-response, namely inflammation and dissociation, defining two different subtypes of patients at risk of suicide. We thus propose the existence of a hypersensitive subtype, defined by underlying neuroinflammatory processes, increased vulnerability to chronic pain and mood disorders, interoceptive hypervigilance, pain hypersensitivity and potentially more persistent suicidal ideation. We further hypothesize a dissociative subtype, characterized by greater trait dissociation, vulnerability to depersonalization and derealization, frequent disintegration of interoceptive processes, transient pain hyposensitivity and abrupt peaks in suicidal ideation.

Biological research on mental pain, social pain and other pains not primarily felt in the body: methodological systematic review

BACKGROUND

Researchers explore the biology of painful experiences not primarily felt in the body ('non-physical pain'), sometimes referred to as mental, social or emotional pain. A critical challenge lies in how to operationalise this subjective experience for biological research, a crucial process for translating findings into clinical practice.

AIMS

To map studies investigating biological features of non-physical pain, focusing on their conceptual features (i.e. terms and definitions of non-physical pain) and methodological characteristics (e.g. experimental paradigms and measures).

METHOD

This methodological systematic review searched reports of primary research on the biological features of non-physical pain across Embase, MEDLINE and Web of Science. Using a meta-research approach, we synthetised results on terms, definitions, populations, experimental paradigms, confounders, measures of non-physical pain and investigation methods (e.g. functional magnetic resonance imaging).

RESULTS

We identified 92 human studies, involving 7778 participants. Overall, 59.1% of the studies did not report any definition of non-physical pain, and 82% of studies did not use a specific measure. Regarding the possibility of translating results to clinical settings, most of the human studies involved only healthy participants (71.7%) and the seven different experimental paradigms used to induce non-physical pain had unknown external validity. Confounders were not considered by 32.4% of the experimental studies. Animal studies were rare, with only four rodent studies.

CONCLUSIONS

Biomedical studies of non-physical pain use heterogeneous concepts with unclear overlaps and methods with unknown external validity. As has been done for physical pain, priority actions include establishing an agreed definition and measurement of non-physical pain and developing experimental paradigms with good external validity.

Emotional Dysregulation and Sexual Risk Behavior in Individuals With Borderline Personality Disorder: Interactions With Psychological Pain, Impulsivity, Anxiety, and Depression

The aim of this study was to assess emotional dysregulation (ED) and sexual risk behavior (SRB) in borderline personality disorder (BPD) and to investigate the relationship between ED, SRB and other clinical variables. Sixty-one women with BPD and 76 healthy controls (HCs) completed: SRB Scale, DERS, Inventory of Statements About Self-Injury, SUPPS-P, HADS, Mental Pain Scale, and BPD Checklist. The BPD group exhibited higher levels of ED, SRB, psychological pain, anxiety, depression, and impulsivity than the HCs. In the BPD group, significant correlations were found between ED, SRB, and psychological pain, impulsivity, and specific dimensions of nonsuicidal self-injury (NSSI). To identify predictors of SRB, stepwise multiple regression analysis was used. The BPD model included five significant predictors accounting for 65% variability: number of sexual partners and age of sexual initiation, NSSI, impulsivity, and ED - lack of emotional clarity, while in HCs, it was influenced by alcohol misuse.

Neuroanatomical and functional correlates in borderline personality disorder: A narrative review

Borderline personality disorder (BPD) is a dysfunctional, stable, and pervasive alteration in personality functioning with the inability to adapt to the environment, mental rigidity, and ego-syntonic. High suicidality in BPD patients underlines the significance of research into its pathology. While extensive research on the psychological and behavioral manifestations of BPD can be found in literature, the neuropsychological aspects of the disorder are still partially unknown, although the roles of certain brain structures in the manifestation of the pathology, such as the amygdala, hippocampus, insula, medial prefrontal and cingulate cortices, nucleus accumbens, and temporo-occipital areas, have already been clarified. This review aims to synthesize current knowledge of the neuroanatomical and functional correlates of BPD, providing insights that may inform future research and therapeutic strategies.

Excitatory Dorsal Lateral Prefrontal Cortex Transcranial Magnetic Stimulation Increases Social Anxiety

Social exclusion refers to the experience of rejection by one or more people during a social event and can induce pain-related sensations. Cyberball, a computer program, is one of the most common tools for analyzing social exclusion. Regions of the brain that underlie social pain include networks linked to the dorsal lateral prefrontal cortex (DLPFC). Specifically, self-directed negative socially induced exclusion is associated with changes in DLPFC activity. Direct manipulation of this area may provide a better understanding of how the DLPFC can influence the perception of social exclusion and determine a causal role of the DLPFC. Transcranial magnetic stimulation (TMS) was applied to both the left and right DLPFC to gauge different reactions to the Cyberball experience. It was found that there were elevated exclusion indices following right DLPFC rTMS; participants consistently felt more excluded when the right DLPFC was excited. This may relate to greater feelings of social pain when the right DLPFC is manipulated. These data demonstrate that direct manipulation of the DLPFC results in changes in responses to social exclusion.

Abnormal Brain Circuits Characterize Borderline Personality and Mediate the Relationship between Childhood Traumas and Symptoms: A mCCA+jICA and Random Forest Approach

Borderline personality disorder (BPD) is a severe personality disorder whose neural bases are still unclear. Indeed, previous studies reported inconsistent findings concerning alterations in cortical and subcortical areas. In the present study, we applied for the first time a combination of an unsupervised machine learning approach known as multimodal canonical correlation analysis plus joint independent component analysis (mCCA+jICA), in combination with a supervised machine learning approach known as random forest, to possibly find covarying gray matter and white matter (GM-WM) circuits that separate BPD from controls and that are also predictive of this diagnosis. The first analysis was used to decompose the brain into independent circuits of covarying grey and white matter concentrations. The second method was used to develop a predictive model able to correctly classify new unobserved BPD cases based on one or more circuits derived from the first analysis. To this aim, we analyzed the structural images of patients with BPD and matched healthy controls (HCs). The results showed that two GM-WM covarying circuits, including basal ganglia, amygdala, and portions of the temporal lobes and of the orbitofrontal cortex, correctly classified BPD against HC. Notably, these circuits are affected by specific child traumatic experiences (emotional and physical neglect, and physical abuse) and predict symptoms severity in the interpersonal and impulsivity domains. These results support that BPD is characterized by anomalies in both GM and WM circuits related to early traumatic experiences and specific symptoms.

A Theoretical Endogenous Opioid Neurobiological Framework for Co-occurring Pain, Trauma, and Non-suicidal Self-injury

PURPOSE OF REVIEW

Individuals with chronic pain are significantly more likely to have experienced overwhelming trauma early and often in key developmental years. There is increasing acknowledgment that childhood trauma disrupts how individuals process and cope with both physical and emotional pain. Emerging studies acknowledge elevated rates of non-suicidal self-injury (NSSI) in chronic pain populations. This review provides a theoretical framework to understand the relationship between NSSI behavior and pain experience in persons with chronic pain and childhood trauma histories. We discuss how NSSI may act to regulate neurobiological (e.g., endogenous opioid systems) and psychological (e.g., heightened negative affect and emotion dysregulation) systems affected by childhood trauma, leading to temporary pain relief and a cycle of negative reinforcement perpetuating NSSI. As these concepts are greatly understudied in pain populations, this review focuses on key areas relevant to chronic pain that may provide a testable, conceptual framework to support hypothesis generation, future empirical investigation, and intervention efforts.

RECENT FINDINGS

See Fig. 1. See Fig. 1.

Co-Occurring Trauma and Non-Suicidal Self-Injury Among People With Chronic Pain: A Systematic Review

PURPOSE OF REVIEW

Trauma and posttraumatic stress are common among individuals with chronic pain and contribute to increased morbidity and impairment. Individuals with trauma and chronic pain may be prone to non-suicidal self-injury, a relatively common yet risky self-regulatory behavior. There is a dearth of research on the intersection of trauma, chronic pain, and non-suicidal self-injury (NSSI). We conducted a systematic review of the extant literature.

RECENT FINDINGS

Five quantitative and eight case reports were identified. Only one quantitative study reported specifically on NSSI. Self-harm rates varied across studies, though appeared elevated among patients with chronic pain. Childhood trauma was linked to this co-occurrence. Causal links between trauma, NSSI, and pain are proposed, highlighting the need for a comprehensive theoretical model. We recommend assessing for childhood trauma when treating patients with chronic pain and querying regarding NSSI when patients present with indicators of NSSI risk and to treat or refer such patients to specialized treatment.

The conceptualization of trauma in psychoanalysis: an introduction

This paper highlights some aspects of the conceptualization of trauma in psychoanalysis and introduces the three subsequent papers by Bernard Chervet, Jan Abrams and Howard Levine. It focuses on the interchange between external and internal reality, the construction of traumatic defensive organizations and the role of reparation and guilt in overcoming the repetition compulsion.

[Pain perception and nonsuicidal self-injurious behavior]

This review focuses on studies of pain threshold and tolerance in individuals with nonsuicidal self-injurious (NSSI) behavior. The data on methods of pain sensitivity studies are presented, with issues in animal modeling of NSSI discussed separately. The results of neuroimaging studies on pain sensitivity in individuals with NSSI are described, along with contribution of genetic factors, psychological variables, and disturbances in opioid and hypothalamic-pituitary-adrenal systems. A critical methodological analysis of the studies on pain sensitivity in individuals with NSSI was performed.

Insomnia in Patients with Borderline Personality Disorder

OBJECTIVE

Both sleep disorders and BPD are prevalent in the population, and one is often a comorbidity of the other. This narrative review aims to assess contemporary literature and scientific databases to provide the current state of knowledge about sleep disorders in patients with borderline personality disorder (BPD) and clinical suggestions for managing sleep disorders in BPD patients and future research direction.

METHODS

Articles were acquired via PubMed and Web of Science, and papers published between January 1980 and October 2020 were extracted. Authors made a series of literature searches using the keywords: Sleep problems, Insomnia, Nightmares, Obstructive sleep apnea, Borderline personality disorder. The inclusion criteria were: published in peer-reviewed journals; studies in humans; or reviews on the related topic; English language. The exclusion criteria were: abstracts from conferences; commentaries; subjects younger than 18 years. After an inspection of the full texts, 42 papers from 101 were selected. Secondary documents from the reference lists of the primary designated papers were searched, assessed for suitability, and included. In total, 71 papers were included in the review process.

RESULTS

Sleep disturbance is common among patients with BPD. Nevertheless, the number of investigations is limited, and the prevalence differs between 5-45%. Studies assessing objective changes in sleep architecture in BPD show inconsistent results. Some of them identify REM sleep changes and a decrease in slow-wave sleep, while other studies found no objective sleep architecture changes. There is also a higher prevalence of nightmares in patients with BPD. Untreated insomnia can worsen BPD symptoms via interference with emotional regulation. BPD itself seems to influence the subjective quality of sleep significantly. Proper diagnosis and treatment of sleep disorders in patients with BPD could lead to better results in therapy. Psychotherapeutic approaches can improve both sleep disorders and BPD symptoms.

CONCLUSION

Recognising and managing sleep disorders in patients with BPD may help alleviate the disorder's symptoms. Treatment of people with BPD may be more effective if the treatment plan explicitly addresses sleep problems. Further research is needed to reach reliable conclusions.

Exploring the links among borderline personality disorder symptoms, trauma, and pain in patients with chronic pain disorders

OBJECTIVE

Chronic pain and borderline personality disorder (BPD) are commonly comorbid and jointly associated with increased symptoms of both disorders and clinical and functional impairment. Little is known, however, about specific links between these disorders. In a cross-sectional study of patients with chronic pain, we compared participants high or low on BPD symptoms on patterns of pain experience and types of child and adult traumas.

METHODS

Adults (N = 181) with chronic pain completed self-reports of pain severity, dimensions of pain experiencing, body coverage of pain, and clinical indicators of central sensitization (i.e., chronic hypersensitivity of the central nervous system), as well as measures of child and adult physical abuse, sexual abuse, trauma, and neglect. Participants also completed the McLean Screening Instrument for BPD.

RESULTS

Participants with clinically significant BPD symptoms (n = 32) reported more childhood sexual trauma, punishment, and neglect, as well as adult physical/sexual trauma, than those without elevated BPD symptoms. Among participants with clinically significant BPD symptoms, affective pain and central sensitization were elevated, potentially explained by heightened negative affect in BPD.

CONCLUSION

BPD symptoms are associated with increased clinical severity among patients with chronic pain as well as a unique manifestation of pain experiencing (i.e., increased affective pain and central sensitization in particular). Childhood trauma of all types is associated with chronic pain and BPD co-occurrence. Researchers and clinicians should assess for BPD in people with chronic pain to enhance conceptual models of the transaction between these disorders and to improve clinical care.

Rejection Sensitivity and Borderline Personality Disorder Features: The Mediating Roles of Attachment Anxiety, Need to Belong, and Self-Criticism

Rejection hypersensitivity has been considered the core feature of patients with borderline personality disorder (BPD). However, little is known about the possible developmental mechanisms that might explain the association between rejection sensitivity and BPD features. The current study investigated the mediating roles of adult attachment, need to belong, and self-criticism in the association between rejection sensitivity and BPD features in 256 healthy adults. Results indicated that attachment anxiety, need to belong, and self-criticism mediated the association between rejection sensitivity and BPD features. However, attachment anxiety and self-criticism did not moderate the mediated association between rejection sensitivity and BPD features. The findings suggest that individuals with high rejection sensitivity are more likely to be anxiously attached to significant others, which might increase the desire to be accepted by others. To satisfy this elevated need to affiliate with others, these individuals might become more self-critical, which may contribute to high BPD features.

A visual analog scale to measure psychological and physical pain: A preliminary validation of the PPP-VAS in two independent samples of depressed patients

OBJECTIVE

Psychological pain lies at the heart of human experience. However, it may also be abnormally intense and/or prolonged in pathological states, with negative outcomes. A simple and reliable measure of psychological pain for clinical use would be useful. In this study, we present a preliminary validation of a simple visual analog scale jointly measuring psychological and physical pain.

METHODS

Two samples of adult (non elderly) depressed patients and healthy controls were independently recruited in two locations in Canada and the USA (N = 46/48 and 200/20, respectively). Six dimensions were successively scored on a paper visual analog scale measuring current, mean and worst pain over the last 15 days, for physical then psychological pain.

RESULTS

All physical and psychological pain dimensions discriminated depressed from non-depressed subjects. Among depressed patients, psychological pain scores were higher than physical pain scores for a given period of assessment. Moreover, correlations between dimensions from the same pain category (physical or psychological) were higher than between different pain categories. Psychological pain was mainly correlated with depression and hopelessness scales while physical pain was mainly correlated with anxiety scales. Secondary analyses showed that psychological (and some physical) pain measures were correlated with suicidal ideas in one location, but no difference in pain scores was found between patients with vs. without a history of suicidal acts in both samples. Childhood trauma positively correlated with several pain dimensions.

CONCLUSION

The PPP-VAS appears to be a valid tool in terms of discriminative capacities and convergent-divergent validities. Validation in different samples, including adolescents and elderly, and in various psychiatric and medical conditions will have to be conducted, in addition to the assessment of concurrent and predictive validities, and the confirmation of sensitivity to change. The role of psychological pain in the suicidal process needs to be further elucidated.

Physical pain recruits the nucleus accumbens during social distress in borderline personality disorder

Patients with borderline personality disorder (BPD) often engage in dangerous self-injurious behaviors (SIBs) as a maladaptive technique to decrease heightened feelings of distress (e.g. negative feelings caused by social exclusion). The reward system has recently been proposed as a plausible neural substrate, which may influence the interaction between social distress and physical pain processing in patients that engage in SIBs. Using functional magnetic resonance imaging (fMRI) in 20 adult BPD patients with a history of SIBs and 23 healthy controls (HCs), we found a hyper-activation of the nucleus accumbens (NAcc) and amygdala when painful stimuli were presented to BPD patients (but not HCs) in a state of heightened distress, induced via social exclusion. This differential NAcc activity was mediated by anxious attachment style, which is a key developmental feature of the disorder. Altogether, these results suggest a neural mechanism underlying the pathophysiology of SIBs in these patients, which is likely reinforced via the reward system.

Psychological Pain, Depression, and Suicide: Recent Evidences and Future Directions

PURPOSE OF REVIEW

The definition of psychological pain is complex. It is a lasting unpleasant and unsustainable feeling characterized by a perception of inability or deficiency of the self, as well as frustrated psychological needs and social disconnection. The aim of our review was to summarize the most recent and updated findings supporting the role of psychological pain in the pathophysiology of depression and suicidal behavior. We also explored the relationship between psychological and physical pain in depression and suicide.

RECENT FINDINGS

Psychological pain is a prominent dimension of depressive disorder and has been associated with higher risk of suicidal ideation and suicidal behavior. Sensitivity to psychological and physical pain is increased in depression. Conversely, higher tolerance to physical pain is associated with suicidal behavior. A better understanding of the pathophysiology of pain processing in depression and suicide offers new therapeutic options for the treatment of depression through the use of analgesic drugs.

Pain-mediated affect regulation is reduced after dialectical behavior therapy in borderline personality disorder: a longitudinal fMRI study

Borderline Personality Disorder (BPD) is characterized by affective instability, but self-injurious behavior appears to have an emotion-regulating effect. We investigated whether pain-mediated affect regulation can be altered at the neural level by residential Dialectical Behavior Therapy (DBT), providing adaptive emotion regulation techniques. Likewise, we investigated whether pain thresholds or the appraisal of pain change after psychotherapy. We investigated 28 patients with BPD undergoing DBT (self-referral), 15 patients with treatment as usual and 23 healthy control subjects at two time points 12 weeks apart. We conducted an fMRI experiment eliciting negative emotions with picture stimuli and induced heat pain to investigate the role of pain in emotion regulation. Additionally, we assessed heat and cold pain thresholds.

At first measurement, patients with BPD showed amygdala deactivation in response to painful stimulation, as well as altered connectivity between left amygdala and dorsal anterior cingulate cortex. These effects were reduced after DBT, as compared with patients with treatment as usual. Pain thresholds did not differ between the patient groups. We replicated the role of pain as a means of affect regulation in BPD, indicated by increased amygdala coupling. For the first time, we could demonstrate that pain-mediated affect regulation can be changed by DBT.

The rewarding nature of provocation-focused rumination in women with borderline personality disorder: a preliminary fMRI investigation

BACKGROUND

Understanding why individuals with borderline personality disorder (BPD) ruminate on prior provocations, despite its negative outcomes, is crucial to improving interventions. Provocation-focused rumination may be rewarding in the short term by amplifying anger and producing feelings of justification, validation, and increased energy, while reducing self-directed negative affect. If provocation-focused rumination is utilized regularly as a rewarding emotion regulation strategy, it could result in increased activation in reward-related neural regions. The present pilot study examined neural correlates of provocation-focused rumination, relative to other forms of thought, in BPD.

METHOD

Functional magnetic resonance imaging (fMRI) was utilized to examine this theory in a pilot study of women diagnosed with BPD (n = 13) and healthy controls (n = 16). All participants received highly critical feedback on a previously written essay in the scanner, followed by prompts to engage in provocation-focused, self-focused, and neutral thought.

RESULTS

Whole-brain analyses showed that in response to the provocation, participants with BPD (compared to controls) demonstrated increased activation in the ventrolateral prefrontal cortex (PFC). BPD participants also showed greater activation in the dorsomedial PFC during provocation-focused rumination (relative to neutral-focus). Subsequent ROI analyses revealed that provocation-focused rumination (compared to neutral-focus) increased activation in the nucleus accumbens for the BPD group only.

CONCLUSIONS

These findings, while preliminary due to the small sample size and limitations of the protocol, provide initial data consistent with the proposed neurobiological mechanism promoting provocation-focused rumination in BPD. Directions for further research are discussed.

Psychological and physical pain as predictors of suicide risk: evidence from clinical and neuroimaging findings

PURPOSE OF REVIEW

Suicide is a multidimensional clinical phenomenon with complex biological, social and psychological risk factors. Therefore, it is imperative for studies to focus on developing a unified understanding of suicide risk that integrates current clinical and neurobiological findings. A recent line of research has implicated different classifications of pain in understanding suicide risk, including the concepts of psychache and pain tolerance. Although psychache is defined as the experience of unbearable psychological pain, pain tolerance refers to the greatest duration or intensity of painful stimuli that one is able to bear. This review will focus on integrating current clinical and neurobiological findings by which psychache and pain tolerance confer suicide risk.

RECENT FINDINGS

Results indicate that psychache has been identified as a significant risk factor for suicide and that psychache may be associated with the neurocircuitry involved in the modulation of physical pain. Converging evidence has also been found linking pain tolerance to self-injurious behaviours and suicide risk. The experience of psychache and physical pain in relation to other predictors of suicide, including reward processing, hopelessness and depression, are further discussed.

SUMMARY

Future research examining the pain-suicide connection is required to understand the mechanism behind clinically relevant risk factors for suicide, which can ultimately inform the construction of empirically supported suicide risk assessment and intervention techniques.

The Addictive Model of Self-Harming (Non-suicidal and Suicidal) Behavior

INTRODUCTION

Behavioral addictions such as gambling, sun-tanning, shopping, Internet use, work, exercise, or even love and sex are frequent, and share many characteristics and common neurobiological and genetic underpinnings with substance addictions (i.e., tolerance, withdrawal, and relapse). Recent literature suggests that both non-suicidal self-injury (NSSI) and suicidal behavior (SB) can also be conceptualized as addictions. The major aim of this mini review is to review the literature and explore the neurobiological and psychological mechanisms underlying the addiction to self-harming behaviors.

METHOD

This is a narrative review. The authors performed literature searches in PubMed and Google for suicidal behavior, self-harming, addiction, and "major repeaters." Given the scarce literature on the topic, a subset of the most closely related studies was selected. The authors also focused on three empirical studies testing the hypothesis that major repeaters (individuals with ≥5 lifetime suicide attempts) represent a distinctive suicidal phenotype and are the individuals at risk of developing an addiction to SB.

RESULTS

The authors reviewed the concept of behavioral addictions and major repeaters, current empirical evidence testing concerning whether or not NSSI and SB can be understood as "addictions," and the putative mechanisms underlying them.

CONCLUSION

Our review suggests that both NSSI and SB can be conceptualized as addictions. This is relevant because if some individual's self-harming behaviors are better conceptualized as an addiction, treatment approaches could be tailored to this addiction.

Differential neural processing of unpleasant haptic sensations in somatic and affective partitions of the insula in non-suicidal self-injury (NSSI)

Altered perception and neural processing of pain have been observed during non-suicidal self-injury (NSSI). Evidence suggests that this phenomenon could be associated with the affective rather than the somatosensory dimension of pain. Sub-partitions of the insula have been suggested to process these different aspects differentially. In the present study, activation within the posterior, middle, and anterior partitions of the insula upon unpleasant electric stimulation was compared between subjects with a history of NSSI and healthy controls. Using functional magnetic resonance imaging (fMRI), we investigated a sample of 30 subjects, 14 of them with a lifetime history of NSSI. Unpleasant electric stimulation to the dorsum of the non-dominant hand was performed at four levels of increasing intensity. Significantly increasing posterior insula activation, which is likely to reflect the somatosensory aspects of unpleasant haptic sensations, was found upon parametrically increasing electric stimulation in both groups. By contrast, activation of the anterior insula, rather related to the more affective aspects of distressing stimuli, was significantly modulated only in the control group, but not in subjects with NSSI. These findings may support present hypotheses of altered processing of the more affective aspects of unpleasant or distressing experiences in NSSI, as a putatively relevant factor for understanding the etiology of this behavior.

Pain Processing after Social Exclusion and Its Relation to Rejection Sensitivity in Borderline Personality Disorder

OBJECTIVE

There is a general agreement that physical pain serves as an alarm signal for the prevention of and reaction to physical harm. It has recently been hypothesized that "social pain," as induced by social rejection or abandonment, may rely on comparable, phylogenetically old brain structures. As plausible as this theory may sound, scientific evidence for this idea is sparse. This study therefore attempts to link both types of pain directly. We studied patients with borderline personality disorder (BPD) because BPD is characterized by opposing alterations in physical and social pain; hyposensitivity to physical pain is associated with hypersensitivity to social pain, as indicated by an enhanced rejection sensitivity.

METHOD

Twenty unmedicated female BPD patients and 20 healthy participants (HC, matched for age and education) played a virtual ball-tossing game (cyberball), with the conditions for exclusion, inclusion, and a control condition with predefined game rules. Each cyberball block was followed by a temperature stimulus (with a subjective pain intensity of 60% in half the cases). The cerebral responses were measured by functional magnetic resonance imaging. The Adult Rejection Sensitivity Questionnaire was used to assess rejection sensitivity.

RESULTS

Higher temperature heat stimuli had to be applied to BPD patients relative to HCs to reach a comparable subjective experience of painfulness in both groups, which suggested a general hyposensitivity to pain in BPD patients. Social exclusion led to a subjectively reported hypersensitivity to physical pain in both groups that was accompanied by an enhanced activation in the anterior insula and the thalamus. In BPD, physical pain processing after exclusion was additionally linked to enhanced posterior insula activation. After inclusion, BPD patients showed reduced amygdala activation during pain in comparison with HC. In BPD patients, higher rejection sensitivity was associated with lower activation differences during pain processing following social exclusion and inclusion in the insula and in the amygdala.

DISCUSSION

Despite the similar behavioral effects in both groups, BPD patients differed from HC in their neural processing of physical pain depending on the preceding social situation. Rejection sensitivity further modulated the impact of social exclusion on neural pain processing in BPD, but not in healthy controls.