Toward identifying reproducible brain signatures of obsessive-compulsive profiles: rationale and methods for a new global initiative.

BACKGROUND: Obsessive-compulsive disorder (OCD) has a lifetime prevalence of 2-3% and is a leading cause of global disability. Brain circuit abnormalities in individuals with OCD have been identified, but important knowledge gaps remain. The goal of the new global initiative described in this paper is to identify robust and reproducible brain signatures of measurable behaviors and clinical symptoms that are common in individuals with OCD. A global approach was chosen to accelerate discovery, to increase rigor and transparency, and to ensure generalizability of results. METHODS: We will study 250 medication-free adults with OCD, 100 unaffected adult siblings of individuals with OCD, and 250 healthy control subjects at five expert research sites across five countries (Brazil, India, Netherlands, South Africa, and the U.S.). All participants will receive clinical evaluation, neurocognitive assessment, and magnetic resonance imaging (MRI). The imaging will examine multiple brain circuits hypothesized to underlie OCD behaviors, focusing on morphometry (T1-weighted MRI), structural connectivity (Diffusion Tensor Imaging), and functional connectivity (resting-state fMRI). In addition to analyzing each imaging modality separately, we will also use multi-modal fusion with machine learning statistical methods in an attempt to derive imaging signatures that distinguish individuals with OCD from unaffected siblings and healthy controls (Aim #1). Then we will examine how these imaging signatures link to behavioral performance on neurocognitive tasks that probe these same circuits as well as to clinical profiles (Aim #2). Finally, we will explore how specific environmental features (childhood trauma, socioeconomic status, and religiosity) moderate these brain-behavior associations. DISCUSSION: Using harmonized methods for data collection and analysis, we will conduct the largest neurocognitive and multimodal-imaging study in medication-free subjects with OCD to date. By recruiting a large, ethno-culturally diverse sample, we will test whether there are robust biosignatures of core OCD features that transcend countries and cultures. If so, future studies can use these brain signatures to reveal trans-diagnostic disease dimensions, chart when these signatures arise during development, and identify treatments that target these circuit abnormalities directly. The long-term goal of this research is to change not only how we conceptualize OCD but also how we diagnose and treat it.

Unresolved-Disorganized Attachment is Associated With Smaller Hippocampus and Increased Functional Connectivity Beyond Psychopathology.

Loss and abuse in children can lead to unresolved-disorganized (UD) attachment. How this condition relates to brain structure and functional connectivity (FC) is unknown. We therefore aimed to investigate gray matter volume (GMV) and resting state functional connectivity (RSFC) correlates of UD attachment in adolescents. Based on previous neuroimaging studies of trauma effects, we hypothesized that the structure of the amygdala and hippocampus and the FC of the latter would be linked to UD attachment. Anatomical and RSFC data were collected from a mixed group of adolescents (N = 74) with symptoms of posttraumatic stress disorder (PTSD) related to childhood sexual abuse (CSA), anxiety/depressive symptoms, and without psychiatric disorder as part of the Emotional Pathways' Imaging Study in Clinical Adolescents (EPISCA). Bilateral volumes of the amygdala and hippocampus were measured using the FMRIB Software Library, and RSFC of the hippocampus was assessed using seed-based correlation. UD attachment was measured using the Adult Attachment Interview. Hierarchical regression and correlation were used to assess the associations between UD status (continuous and categorical), brain structure, and FC, adjusting for a general psychopathology factor, puberty stage, gender, age, and IQ. UD attachment was associated with a smaller left hippocampal volume, R2 = .23, and a higher level of FC between the hippocampus and the middle temporal gyrus and lateral occipital cortex. The associations among UD attachment, specific brain structure, and FC across psychopathological classifications shows promise for dimensional complements to the dominant classificatory approach in clinical research and practice.

Spanish Abstracts by Asociación Chilena de Estrés Traumático (ACET) El apego desorganizado no resuelto asociado con un menor hipocampo y un incremento de la conectividad funcional más allá de la psicopatología APEGO, HIPOCAMPO Y CONECTIVIDAD FUNCIONAL. Las pérdidas y el abuso en niños pueden conllevar a un apego desorganizado no resuelto (DN). La forma en que esta condición se relaciona con la estructura cerebral y conectividad funcional (CF) es desconocida. Por lo tanto, nuestro objetivo fue investigar el volumen de materia gris (VMG) y los correlatos de la conectividad funcional en estado de reposo (CFER) de DN en adolescentes. Basado en estudios previos de neuroimágenes sobre los efectos del trauma, hipotetizamos que la estructura de la amígdala e hipocampo y la CF de este último podría estar relacionado con DN. Los datos anatómicos y de CFER fueron recolectados de un grupo mixto de adolescentes (N = 74) con síntomas de trastorno de estrés postraumático (TEPT) relacionado con abuso sexual infantil (ASI), síntomas de ansiedad/depresión, y sin trastornos psiquiátricos, como parte del Estudio de Imágenes de Vías Emocionales en Clínica Adolescente (EPISCA en su sigla en inglés). Volúmenes bilaterales de la amígdala e hipocampo fueron evaluados usando el software de biblioteca FMRIB, y la CFER del hipocampo fue evaluada usando la correlación basada en semillas. La DN fue medido utilizando la Entrevista de Apego Adulto. Regresiones jerárquicas y correlaciones fueron utilizadas para evaluar las asociaciones entre DN (continuo y categórico), estructura cerebral, y CF, ajustando un factor general de psicopatología, etapa de pubertad, género, edad y CI. DN fue asociado con un menor volumen del hipocampo izquierdo, R2 = .23, y altos niveles de CF entre el hipocampo y giro temporal medio y la corteza occipital lateral. La asociación de DN con una estructura cerebral especifica y CF a través de clasificaciones psicopatológicas es prometedora como complementos dimensionales al enfoque clasificatorio dominante en la investigación y práctica clínica.