Treatment of dissociative identity disorder: leveraging neurobiology to optimize success.

INTRODUCTION: Dissociative identity disorder (DID) is a treatable mental health condition that is associated with a range of psychobiological manifestations. However, historical controversy, modern day misunderstanding, and lack of professional education have prevented accurate treatment information from reaching most clinicians and patients. These obstacles also have slowed empirical efforts to improve treatment outcomes for people with DID. Emerging neurobiological findings in DID provide essential information that can be used to improve treatment outcomes. AREAS COVERED: In this narrative review, the authors discuss symptom characteristics of DID, including dissociative self-states. Current treatment approaches are described, focusing on empirically supported psychotherapeutic interventions for DID and pharmacological agents targeting dissociative symptoms in other conditions. Neurobiological correlates of DID are reviewed, including recent research aimed at identifying a neural signature of DID. EXPERT OPINION: Now is the time to move beyond historical controversy and focus on improving DID treatment availability and efficacy. Neurobiological findings could optimize treatment by reducing shame, aiding assessment, providing novel interventional brain targets and guiding novel pharmacologic and psychotherapeutic interventions. The inclusion of those with lived experience in the design, planning and interpretation of research investigations is another powerful way to improve health outcomes for those with DID.

Hippocampal and amygdala volumes vary with residential proximity to toxicants at Birmingham, Alabama's 35th Avenue Superfund site.

Exposure to environmental toxicants have serious implications for the general health and well-being of children, particularly during pivotal neurodevelopmental stages. The Environmental Protection Agency's (EPA) Superfund program has identified several areas (Superfund sites) across the United States with high levels of environmental toxicants, which affect the health of many residents in nearby communities. Exposure to these environmental toxicants has been linked to changes in the structure and function of the brain. However, limited research has investigated the relationship between the proximity of childhood homes to a Superfund site and the development of subcortical structures like the hippocampus and amygdala. The present study investigated the hippocampal and amygdala volumes of young adults in relation to the proximity of their childhood homes to Birmingham, Alabama's 35th Avenue Superfund site. Forty participants who either lived within or adjacent to the Superfund site (Proximal group; n = 20) or who lived elsewhere in the greater Birmingham metropolitan area (Distal group; n = 20) were included in this study. Both groups were matched on age, sex, race, and years of education. Magnetic resonance imaging (MRI) was used to compare the gray matter volume of the hippocampus and amygdala between groups. Differences in bilateral hippocampal and left amygdala volumes were observed. Specifically, hippocampal and amygdala volumes were greater in the Proximal than Distal group. These findings suggest that the proximity of children's homes to environmental toxicants may impact the development of the hippocampus and amygdala. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

White Matter Microstructure in the Young Adult Brain Varies with Neighborhood Disadvantage in Adolescence.

Neighborhood disadvantage and community violence are common in poor, urban communities and are risk factors for emotional dysfunction. Emotional processes are supported by neural circuitry that includes the prefrontal cortex (PFC), hippocampus, amygdala, and hypothalamus. These brain regions are connected by white matter pathways that include the cingulum bundle, uncinate fasciculus, stria terminalis, and fornix. Emotional function varies with the microstructure of these white matter pathways. However, it is not clear whether the microstructure of these pathways varies with risk factors for emotional dysfunction (e.g., neighborhood disadvantage and violence exposure). Therefore, determining the relationships between neighborhood disadvantage, violence exposure, and white matter microstructure may offer insight into the neural mechanisms by which adverse life experiences alter developing neural systems. The current study investigated the association that exposure to neighborhood disadvantage and violence have with the quantitative anisotropy (QA), a measure of the amount of directional water diffusion, of the cingulum bundle, uncinate fasciculus, stria terminalis, and fornix. Neighborhood disadvantage (Mage = 11.20) and violence exposure (MW1age = 11.20; MW2age = 13.05; MW3age = 16.20; MW4age = 19.25) were assessed during adolescence and participants returned for magnetic resonance imaging as young adults (N = 303; Mage = 20.25, SD = 1.55), during which diffusion weighted brain images were collected. The QA of the cingulum bundle, uncinate fasciculus, and stria terminalis/fornix varied negatively with neighborhood disadvantage such that the QA of these white matter tracts decreased as neighborhood disadvantage increased. Violence exposure was not related to QA in any tract (i.e., cingulum bundle, uncinate fasciculus, and stria terminalis/fornix) after correction for multiple comparisons. These results suggest that an adolescent's neighborhood may play an important role in the microstructure (i.e., QA) of white matter pathways that connect brain regions that support emotional function.

Stress-elicited neural activity in young adults varies with childhood sexual abuse.

OBJECTIVE: Childhood physical and sexual abuse are stressful experiences that may alter the emotional response to future stressors. Stress-related emotional function is supported by brain regions that include the prefrontal cortex (PFC), hippocampus, and amygdala. The present study investigated whether childhood physical and sexual abuse are associated with stress-elicited brain activity in young adulthood. METHODS: Participants (N = 300; Mage = 20.0; 151 female) completed a psychosocial stress task during functional magnetic resonance imaging (fMRI). Measures of physical and sexual abuse were included in a linear mixed effects model to estimate the unique relationship each type of childhood abuse had with stress-elicited brain activity. RESULTS: Stress-elicited dorsolateral PFC, ventromedial PFC, and hippocampal activity decreased as the frequency of childhood sexual abuse increased. There were no regions in which stress-elicited activation varied with physical abuse. CONCLUSIONS: The present findings suggest there is a unique relationship between childhood sexual abuse and the stress-elicited PFC and hippocampal activity of young adults that is not observed following childhood physical abuse. SIGNIFICANCE: These findings may have important implications for understanding the mechanisms by which childhood sexual abuse impacts the development of future psychopathology.

Examining Sex and Racial/Ethnic Differences in Co-use of Alcohol, Cannabis, and Cigarettes in a Community Sample of Adolescents.

INTRODUCTION: Although adolescents often co-use alcohol, cigarettes, and cannabis, little is known about sex and racial/ethnic differences in the co-use of these substances. Therefore, this investigation examined sex and racial/ethnic differences in alcohol, cigarette, and cannabis co-use in a large and ethnically diverse group. Methods: Participants were drawn from a large, multi-site study of adolescents from three regions in the United States (N = 4,129; Mage=16.10 years, SD = 0.59; 51% female, 49% male; 37% Black, 37% Hispanic, 25% White). Participants were categorized into eight mutually exclusive groups based on their self-reported use of alcohol, cannabis, and cigarettes in the last 30 days. Results: Unadjusted multinomial logistic regression revealed that males were more likely than females to use cannabis-only and to co-use all three substances. Additionally, Black and Hispanic adolescents were more likely to use cannabis-only, while White adolescents were more likely than Black and Hispanic adolescents to co-use alcohol and cigarettes. After adjusting for other sociodemographic variables (age, household income, parental education, and parent marital status), males were more likely to use cannabis-only than females; White youth were more likely than Hispanic youth to use cigarettes only and co-use cigarettes and alcohol. White youth were more likely than Black youth to co-use alcohol and cigarettes and co-use all three substances. Discussion: These results indicate sex and racial/ethnic differences in substance co-use that were not explained by socioeconomic factors. Results of this work suggest potential strategies for targeted prevention efforts and underscore the importance of continued efforts to better understand patterns of alcohol and substance co-use.

Implicit Mental Motor Imagery Task Demonstrates a Distortion of the Body Schema in Patients With Eating Disorders.

OBJECTIVES: A rich body of literature has established the role of body image distortion and dissatisfaction in the development and maintenance of eating disorders. However, many of the currently used techniques require explicit comparison of the person's body to an external stimulus. As the body schema is a largely unconscious construct, explicit comparison tasks may reflect a proxy, rather than the body schema itself. METHODS: Here we use an implicit mental motor imagery (MMI) task to interrogate the body schema in healthy control participants (N=40) and participants at a residential eating disorder treatment center (N=42). By comparing the time it takes to imagine making a movement along a part of the body to the time it takes to actually make the same movement, we were able to assess participants' mental image of their body (i.e., body schema). RESULTS: We found that participants with eating disorders, but not healthy controls, exhibited distortions of the body schema such that they believed their abdomen, buttocks, and thighs to be larger than they really are. Additionally, the MMI task used here provided information above and beyond traditional self-report measures (i.e., Body Shape Questionnaire). Together the MMI task and traditional measures provide the most information. CONCLUSIONS: Findings using the novel MMI task are in line with the literature; participants with eating disorders consider themselves to be larger than they truly are. Taken together, results of this study suggest that MMI tasks provide complementary information to traditional self-report measures. (JINS, 2018, 24, 715-723).

Fields or flows? A comparative metaanalysis of transcranial magnetic and direct current stimulation to treat post-stroke aphasia.

PURPOSE: Aphasia-acquired loss of the ability to understand or express language-is a common and debilitating neurological consequence of stroke. Evidence suggests that transcranial magnetic (TMS) or direct current stimulation (tDCS) can significantly improve language outcomes in patients with aphasia (PWA). However, the relative efficacy between TMS and tDCS has not yet been explored. Mechanistic and methodological differences, patient inclusion/exclusion criteria and experimental designs may influence observed treatment benefits. METHODS: We conducted a systematic review and meta-analyses of TMS and tDCS treatment studies in PWA. Standard mean difference (SMD) for changes in picture naming accuracy was estimated; pooled SMDs were compared using a random-effects model. RESULTS: Eight TMS (N = 143) and 8 tDCS studies (N = 140) met our inclusion criteria. Pooled SMDs of 0.448 (p < 0.001) in favor of TMS, and 0.395 (p < 0.001) in favor of tDCS were found. Between-subject designs were more common in subacute and within/crossover designs in chronic patients. TMS SMDs were significant in both chronic (SMD = 0.348) and subacute (SMD = 0.667) populations while those for tDCS were significant in chronic (SMD = 0.320) but not in subacute (SMD = 0.283) PWA. CONCLUSIONS: The magnitude of treatment effects appears to be consistent between TMS and tDCS in PWA. Larger-scale clinical trials should further substantiate our findings.