White matter tract alterations in schizophrenia identified by DTI-based probabilistic tractography: a multisite harmonisation study.

INTRODUCTION: It has been suggested that schizophrenia involves dysconnectivity between functional brain regions and also the white matter structural disorganisation. Thus, diffusion tensor imaging (DTI) has widely been used for studying schizophrenia. However, most previous studies have used the region of interest (ROI) based approach. We, therefore, performed the probabilistic tractography method in this study to reveal the alterations of white matter tracts in the schizophrenia brain. METHODS: A total of four different datasets consisted of 189 patients with schizophrenia and 213 healthy controls were investigated. We performed retrospective harmonisation of raw diffusion MRI data by dMRIharmonisation and used the FMRIB Software Library (FSL) for probabilistic tractography. The connectivities between different ROIs were then compared between patients and controls. Furthermore, we evaluated the relationship between the connection probabilities and the symptoms and cognitive measures in patients with schizophrenia. RESULTS: After applying Bonferroni correction for multiple comparisons, 11 different tracts showed significant differences between patients with schizophrenia and healthy controls. Many of these tracts were associated with the basal ganglia or cortico-striatal structures, which aligns with the current literature highlighting striatal dysfunction. Moreover, we found that these tracts demonstrated statistically significant relationships with few cognitive measures related to language, executive function, or processing speed. CONCLUSION: We performed probabilistic tractography using a large, harmonised dataset of diffusion MRI data, which enhanced the statistical power of our study. It is important to note that most of the tracts identified in this study, particularly callosal and cortico-striatal streamlines, have been previously implicated in schizophrenia within the current literature. Further research with harmonised data focusing specifically on these brain regions could be recommended.

Negative effects during multicomponent group-based treatment: A multisite study.

Objective Negative effects (NEs) in group treatments remain an under-researched area. This study aimed to explore the prevalence of various types of NEs in a multicomponent group-based treatment and to determine their predictors. Method: A total of 330 patients participating in a multicomponent group-based treatment were recruited across seven clinical sites. At the end of treatment, the Negative Effects Questionnaire (NEQ) was used to measure NEs. Item-level descriptive analysis was conducted to explore the prevalence of various types of NEs, and structural equation modeling was used to determine predictors of these NEs. Results: The most frequently reported type of NEs was the worsening of symptoms, and the single most frequently reported item was the resurfacing of unpleasant memories. Predictors of NEs included the overall distress level, alexithymia, attachment avoidance, low working alliance, problem actuation, and worse outcomes; psychological mindedness was a protective factor. Conclusion: Patients who experience higher levels of distress at the beginning of treatment, who perceive the group working alliance as problematic, and who experience high in-session emotional arousal related to their problem seem to be especially prone to reporting NEs. Furthermore, the findings do not support the assumption that NEs are a prerequisite for therapeutic change.Trial registration: ISRCTN.org identifier: ISRCTN13532466.

Consistent brain structural abnormalities and multisite individualised classification of schizophrenia using deep neural networks.

BACKGROUND: Previous analyses of grey and white matter volumes have reported that schizophrenia is associated with structural changes. Deep learning is a data-driven approach that can capture highly compact hierarchical non-linear relationships among high-dimensional features, and therefore can facilitate the development of clinical tools for making a more accurate and earlier diagnosis of schizophrenia. AIMS: To identify consistent grey matter abnormalities in patients with schizophrenia, 662 people with schizophrenia and 613 healthy controls were recruited from eight centres across China, and the data from these independent sites were used to validate deep-learning classifiers. METHOD: We used a prospective image-based meta-analysis of whole-brain voxel-based morphometry. We also automatically differentiated patients with schizophrenia from healthy controls using combined grey matter, white matter and cerebrospinal fluid volumetric features, incorporated a deep neural network approach on an individual basis, and tested the generalisability of the classification models using independent validation sites. RESULTS: We found that statistically reliable schizophrenia-related grey matter abnormalities primarily occurred in regions that included the superior temporal gyrus extending to the temporal pole, insular cortex, orbital and middle frontal cortices, middle cingulum and thalamus. Evaluated using leave-one-site-out cross-validation, the performance of the classification of schizophrenia achieved by our findings from eight independent research sites were: accuracy, 77.19-85.74%; sensitivity, 75.31-89.29% and area under the receiver operating characteristic curve, 0.797-0.909. CONCLUSIONS: These results suggest that, by using deep-learning techniques, multidimensional neuroanatomical changes in schizophrenia are capable of robustly discriminating patients with schizophrenia from healthy controls, findings which could facilitate clinical diagnosis and treatment in schizophrenia.

Differentiation of schizophrenia using structural MRI with consideration of scanner differences: A real-world multisite study.

AIM: Neuroimaging studies have revealed that patients with schizophrenia exhibit reduced gray matter volume in various regions. With these findings, various studies have indicated that structural MRI can be useful for the diagnosis of schizophrenia. However, multisite studies are limited. Here, we evaluated a simple model that could be used to differentiate schizophrenia from control subjects considering MRI scanner differences employing voxel-based morphometry. METHODS: Subjects were 541 patients with schizophrenia and 1252 healthy volunteers. Among them, 95 patients and 95 controls (Dataset A) were used for the generation of regions of interest (ROI), and the rest (Dataset B) were used to evaluate our method. The two datasets were comprised of different subjects. Three-dimensional T1-weighted MRI scans were taken for all subjects and gray-matter images were extracted. To differentiate schizophrenia, we generated ROI for schizophrenia from Dataset A. Then, we determined volume within the ROI for each subject from Dataset B. Using the extracted volume data, we calculated a differentiation feature considering age, sex, and intracranial volume for each MRI scanner. Receiver-operator curve analyses were performed to evaluate the differentiation feature. RESULTS: The area under the curve ranged from 0.74 to 0.84, with accuracy from 69% to 76%. Receiver-operator curve analysis with all samples revealed an area under the curve of 0.76 and an accuracy of 73%. CONCLUSION: We moderately successfully differentiated schizophrenia from control using structural MRI from differing scanners from multiple sites. This could be useful for applying neuroimaging techniques to clinical settings for the accurate diagnosis of schizophrenia.

Reflections on the Use of Audio Diaries to Access Young People's Lived Experiences of HIV in Zimbabwe.

This methodological article reflects on the contribution audio diaries can make to accessing important, and commonly silenced, dimensions of the lived experience of growing up with HIV and their acceptability to children. Audio diaries were used by 12 young people, aged 11 to 13 years, as part of a longitudinal qualitative study embedded within the Anti-Retroviral Research for Watoto (ARROW) clinical trial. The method provided an alternative means for young people to express detailed reflections on their day-to-day encounters, as well as ordinarily silenced topics, including hidden and suppressed emotions regarding the circumstance surrounding their perinatal infection. Although the audio diary has great potential as method, its efficacy rests on young people's understanding of how to use it. There are ethical challenges around maintaining confidentiality while participants are in possession of the diaries and provision of appropriate support. The technology used in the study was in many ways cumbersome compared with opportunities increasingly available.

Perceptions of the care received from Australian palliative care services: A caregiver perspective.

ABSTRACTBackground:Caregiver satisfaction and experience surveys help health professionals to understand, measure, and improve the quality of care provided for patients and their families. OBJECTIVE: Our aim was to explore caregiver perceptions of the care received from Australian specialist palliative care services. METHOD: Caregivers of patients receiving palliative care in services registered with Australia's Palliative Care Outcomes Collaboration were invited to participate in a caregiver survey. The survey included the FAMCARE-2 and four items from the Ongoing Needs Identification: Caregiver Profile questionnaire. RESULTS: Surveys were completed by 1,592 caregivers from 49 services. Most respondents reported high satisfaction and positive experiences. Caregivers receiving care from community-based palliative care teams were less satisfied with the management of physical symptoms and comfort (odds ratio [OR] = 0.29; 95% confidence interval [CI95%] = 0.14, 0.59), with patient psychological care (OR = 0.56; CI95% = 0.32, 0.98), and with family support (OR = 0.52; CI95% = 0.35, 0.77) than caregivers of patients in an inpatient setting. If aged over 60 years, caregivers were less likely to have their information needs met regarding available support services (OR = 0.98; CI95% = 0.97, 0.98) and carer payments (OR = 0.99; CI95% = 0.98, 1.00). Also, caregivers were less likely to receive adequate information about carer payments if located in an outer regional area (OR = 0.41; CI95% = 0.25, 0.64). With practical training, caregivers receiving care from community services reported inadequate information provision to support them in caring for patients (OR = 0.60; CI95% = 0.45, 0.81). SIGNIFICANCE OF RESULTS: While our study identified caregivers as having positive and satisfactory experiences across all domains of care, there is room for improvement in the delivery of palliative care across symptom management, as well as patient and caregiver support, especially in community settings. Caregiver surveys can facilitate the identification and evaluation of both patients' and caregivers' experiences, satisfaction, distress, and unmet needs.

A COMPREHENSIVE EXAMINATION OF WHITE MATTER TRACTS AND CONNECTOMETRY IN MAJOR DEPRESSIVE DISORDER.

BACKGROUND: Major depressive disorder (MDD) is a debilitating disorder characterized by widespread brain abnormalities. The literature is mixed as to whether or not white matter abnormalities are associated with MDD. This study sought to examine fractional anisotropy (FA) in white matter tracts in individuals with MDD using diffusion tensor imaging (DTI). METHODS: 139 participants with MDD and 39 healthy controls (HC) in a multisite study were included. DTI scans were acquired in 64 directions and FA was determined in the brain using four methods: region of interest (ROI), tract-based spatial statistics (TBSS), and diffusion tractography. Diffusion connectometry was used to identify white matter pathways associated with MDD. RESULTS: There were no significant differences when comparing FA in MDD and HC groups using any method. In the MDD group, there was a significant relationship between depression severity and FA in the right medial orbitofrontal cortex, and between age of onset of MDD and FA in the right caudal anterior cingulate cortex using the ROI method. There was a significant relationship between age of onset and connectivity in the thalamocortical radiation, inferior longitudinal fasciculus, and cerebellar tracts using diffusion connectometry. CONCLUSIONS: The lack of group differences in FA and connectometry analysis may result from the clinically heterogenous nature of MDD. However, the relationship between FA and depression severity may suggest a state biomarker of depression that should be investigated as a potential indicator of response. Age of onset may also be a significant clinical feature to pursue when studying white matter tracts.

How reliable are gray matter disruptions in specific reading disability across multiple countries and languages? Insights from a large-scale voxel-based morphometry study.

The neural basis of specific reading disability (SRD) remains only partly understood. A dozen studies have used voxel-based morphometry (VBM) to investigate gray matter volume (GMV) differences between SRD and control children, however, recent meta-analyses suggest that few regions are consistent across studies. We used data collected across three countries (France, Poland, and Germany) with the aim of both increasing sample size (236 SRD and controls) to obtain a clearer picture of group differences, and of further assessing the consistency of the findings across languages. VBM analysis reveals a significant group difference in a single cluster in the left thalamus. Furthermore, we observe correlations between reading accuracy and GMV in the left supramarginal gyrus and in the left cerebellum, in controls only. Most strikingly, we fail to replicate all the group differences in GMV reported in previous studies, despite the superior statistical power. The main limitation of this study is the heterogeneity of the sample drawn from different countries (i.e., speaking languages with varying orthographic transparencies) and selected based on different assessment batteries. Nevertheless, analyses within each country support the conclusions of the cross-linguistic analysis. Explanations for the discrepancy between the present and previous studies may include: (1) the limited suitability of VBM to reveal the subtle brain disruptions underlying SRD; (2) insufficient correction for multiple statistical tests and flexibility in data analysis, and (3) publication bias in favor of positive results. Thus the study echoes widespread concerns about the risk of false-positive results inherent to small-scale VBM studies.

Multisite studies for optimization of a highly efficient culture assay used for in vitro detection of residual undifferentiated human pluripotent stem cells intermingled in cell therapy products.

Introduction: MEASURE2 (Multisite Evaluation Study on Analytical Methods for Non-clinical Safety Assessment of HUman-derived REgenerative Medical Products 2) is a Japanese experimental public-private partnership initiative that aims to standardize testing methods for tumorigenicity evaluation of human pluripotent stem cell (hPSC)-derived cell therapy products (CTPs). MEASURE2 organized multisite studies to optimize the methodology of the highly efficient culture (HEC) assay, a sensitive culture-based in vitro assay for detecting residual undifferentiated hPSCs in CTPs. Methods: In these multisite studies, 1) the efficiency of colony formation by human induced pluripotent stem cells (hiPSCs) under two different culture conditions and 2) the sorting efficiency of microbeads conjugated to various anti-hPSC markers during hiPSC enrichment were evaluated using samples in which hiPSCs were spiked into hiPSC-derived mesenchymal stem cells. Results: The efficiency of colony formation was significantly higher under culture conditions with the combination of Chroman 1, Emricasan, Polyamines, and Trans-ISRIB (CEPT) than with Y-27632, which is widely used for the survival of hPSCs. Between-laboratory variance was also smaller under the condition with CEPT than with Y-27632. The sorting efficiency of microbeads conjugated with the anti-Tra-1-60 antibody was sufficiently higher (>80%) than those of the other various microbeads investigated. Conclusions: Results of these multisite studies are expected to contribute to improvements in the sensitivity and robustness of the HEC assay, as well as to the future standardization of the tumorigenicity risk assessment of hPSC-derived CTPs.

International evaluation study of a highly efficient culture assay for detection of residual human pluripotent stem cells in cell therapies.

Aim & methods: The Health and Environmental Sciences Institute Cell Therapy-TRAcking, Circulation & Safety Technical Committee launched an international, multisite study to evaluate the sensitivity and reproducibility of the highly efficient culture (HEC) assay, an in vitro assay to detect residual undifferentiated human pluripotent stem cells (hPSCs) in cell therapy products. Results: All facilities detected colonies of human induced pluripotent stem cells (hiPSCs) when five hiPSCs were spiked into 1 million hiPSC-derived cardiomyocytes. Spiking with a trace amount of hiPSCs revealed that repeatability accounts for the majority of reproducibility while the true positive rate was high. Conclusion: The results indicate that the HEC assay is highly sensitive and robust and can be generally applicable for tumorigenicity evaluation of hPSC-derived cell therapy products.

Multisite harmonization of diffusion tensor image analysis along the perivascular space using the COMBined Association Test.

PURPOSE: This multisite study aimed to use the COMBined Association Test (COMBAT), a harmonization technique that uses regression of covariates with an empirical Bayesian framework, to harmonize diffusion tensor image analysis along the perivascular space (DTI-ALPS) variations caused by scanner, site, and protocol differences. MATERIALS AND METHODS: This study included multisite diffusion magnetic resonance imaging (dMRI) data of 45 patients with Alzheimer's disease (AD) and 82 cognitively normal (CN) participants from the AD neuroimaging initiative database. The dMRI data were obtained with two b values (0 and 1000 s/mm2) from 27 institutions and three different 3-Tesla MRI scanners (two vendors). The ALPS index was calculated from multisite dMRI data, and COMBAT was used to harmonize the factors causing site variations. Welch's t test was used, Cohen's d was calculated to compare the difference in the ALPS index between AD and CN before and after harmonization, and Pearson's correlation coefficient was calculated to assess the relationships between the ALPS index and the cognitive score, [18F] fluorodeoxyglucose (FDG)-positron emission tomography (PET), and [18F] florbetapir (AV45)-PET standardized uptake value ratios (SUVRs). RESULTS: COMBAT harmonized scanner differences and increased Cohen's d of the left and right ALPS indexes between AD and CN from 0.288 to 0.438 and 0.328 to 0.480, respectively. The ALPS indexes were significantly different between AD and CN after harmonization (P < 0.05) but not before it. Moreover, Pearson's correlation coefficients between the ALPS index and cognitive score, FDG-PET, and AV45-PET SUVRs were higher after harmonization than before it. CONCLUSION: This study demonstrates the application of COMBAT harmonization to eliminate between-scanner, site, and protocol variations in the ALPS index calculated from DTI-ALPS using dMRI and possibly facilitate the use of the ALPS index in multi-center studies.

Application of a Machine Learning Algorithm for Structural Brain Images in Chronic Schizophrenia to Earlier Clinical Stages of Psychosis and Autism Spectrum Disorder: A Multiprotocol Imaging Dataset Study.

BACKGROUND AND HYPOTHESIS: Machine learning approaches using structural magnetic resonance imaging (MRI) can be informative for disease classification; however, their applicability to earlier clinical stages of psychosis and other disease spectra is unknown. We evaluated whether a model differentiating patients with chronic schizophrenia (ChSZ) from healthy controls (HCs) could be applied to earlier clinical stages such as first-episode psychosis (FEP), ultra-high risk for psychosis (UHR), and autism spectrum disorders (ASDs). STUDY DESIGN: Total 359 T1-weighted MRI scans, including 154 individuals with schizophrenia spectrum (UHR, n = 37; FEP, n = 24; and ChSZ, n = 93), 64 with ASD, and 141 HCs, were obtained using three acquisition protocols. Of these, data regarding ChSZ (n = 75) and HC (n = 101) from two protocols were used to build a classifier (training dataset). The remainder was used to evaluate the classifier (test, independent confirmatory, and independent group datasets). Scanner and protocol effects were diminished using ComBat. STUDY RESULTS: The accuracy of the classifier for the test and independent confirmatory datasets were 75% and 76%, respectively. The bilateral pallidum and inferior frontal gyrus pars triangularis strongly contributed to classifying ChSZ. Schizophrenia spectrum individuals were more likely to be classified as ChSZ compared to ASD (classification rate to ChSZ: UHR, 41%; FEP, 54%; ChSZ, 70%; ASD, 19%; HC, 21%). CONCLUSION: We built a classifier from multiple protocol structural brain images applicable to independent samples from different clinical stages and spectra. The predictive information of the classifier could be useful for applying neuroimaging techniques to clinical differential diagnosis and predicting disease onset earlier.

Mental Health Risk Profiles and Related Substance Use During Coronavirus Pandemic Among College Students Who Use Substances.

College students have shown elevated mental distress during the coronavirus disease of 2019 (COVID-19). The extent and persistence of mental distress as COVID-19 restrictions have continued is unclear. This study used latent profile analysis to identify student mental health risk subgroups and to evaluate subgroups in relation with substance use. A four-profile solution was supported with a sample of 930 college students (69.6% female, 58.1% White) from 11 US-based institutions. Students were characterized by slight mental health symptoms, mild mental health symptoms, moderate-to-severe mental health symptoms with mild psychosis/substance use, and severe mental health symptoms. The severe profile comprised more ethnoracial or sexual minorities and students impacted from COVID-19. Whereas the severe profile had more alcohol-related consequences, the slight profile had fewer cannabis-related consequences. COVID-19 has exacerbated college student risks for psychiatric disorders. Students of diverse backgrounds and more impacted by COVID-19 show disproportionately more mental distress and related substance use.

Planning and managing a complex multisite study in the age of technology.

A 2-year long, multisite research study that evaluated cardiopulmonary resuscitation skill decay among nursing students was conducted at 10 schools of nursing across the United States. The study was conducted in two phases and required carefully timed sessions for skill performance. Multisite studies in nursing education need to be carefully planned. Time delays should be anticipated with processes and Institutional Review Board protocols across sites. All team members were trained and consistently supported during the entire study. While challenges and obstacles were identified, innovative solutions were implemented that assisted the research team to successfully complete the study. The use of new and existing technology allowed the team to surmount many of the challenges encountered in this study. The purpose of this article is to describe the logistics, processes, challenges, and lessons learned related to conducting a complex multisite study.

Decentralized and reproducible geocoding and characterization of community and environmental exposures for multisite studies.

OBJECTIVE: Geocoding and characterizing geographic, community, and environmental characteristics of study participants is frequently done in epidemiological studies. However, participant addresses are identifiable protected health information (PHI) and geocoding must be conducted in a Health Insurance Portability and Accountability Act-compliant manner. Our objective was to create a software application for this process that addresses limitations in current approaches. MATERIALS AND METHODS: We used a containerization platform to create DeGAUSS (Decentralized Geomarker Assessment for Multi-Site Studies), a software application that facilitates reproducible geocoding and geomarker assessment while maintaining the confidentiality of PHI. To validate the software, 215 350 addresses in Hamilton County, Ohio, were geocoded using DeGAUSS, ArcGIS, Google, and SAS and compared to a gold-standard approach. We distributed the DeGAUSS software to sites in an ongoing multisite study (Electronic Medical Records and Genomics, or eMERGE), and individual sites independently geocoded and assigned median census tract-level income and distance to nearest major roadway to their participants' addresses, removed associated PHI, and returned deidentified data. RESULTS: Within a multisite study, 52 244 study participants' addresses across 5 sites were geocoded with a median distance to roadway of 10 022m and a median census tract income of $57 266, demonstrating the feasibility of DeGAUSS within a multisite study. Compared to other commonly used geocoding platforms, DeGAUSS had similar geocoding and geomarker assessment accuracies. CONCLUSION: The open source DeGAUSS software overcomes multiple challenges in the use of address data in multisite studies and also serves as a more general reproducible research tool for geocoding and geomarker assessment.

The exposure-response relationship between temperature and childhood hand, foot and mouth disease: A multicity study from mainland China.

BACKGROUND: Hand, foot and mouth disease (HFMD) is a rising public health issue in the Asia-Pacific region. Numerous studies have tried to quantify the relationship between meteorological variables and HFMD but with inconsistent results, in particular for temperature. We aimed to characterize the relationship between temperature and HFMD in various locations and to investigate the potential heterogeneity. METHODS: We retrieved the daily series of childhood HFMD counts (aged 0-12 years) and meteorological variables for each of 143 cities in mainland China in the period 2009-2014. We fitted a common distributed lag nonlinear model allowing for over dispersion to each of the cities to obtain the city-specific estimates of temperature-HFMD relationship. Then we pooled the city-specific estimates through multivariate meta-regression with city-level characteristics as potential effect modifiers. RESULTS: We found that the overall pooled temperature-HFMD relationship was shown as an approximately inverted V shape curve, peaking at the 91th percentile of temperature with a risk ratio of 1.30 (95% CI: 1.23-1.37) compared to its 50th percentile. We found that 68.5% of the variations of city-specific estimates was attributable to heterogeneity. We identified rainfall and altitude as the two main effect modifiers. CONCLUSIONS: We found a nonlinear relationship between temperature and HFMD. The temperature-HFMD relationship varies depending on geographic and climatic conditions. The findings can help us deepen the understanding of weather-HFMD relationship and provide evidences for related public health decisions.

Does 'Time Together' increase quality of interaction and decrease stress? A study protocol of a multisite nursing intervention in psychiatric inpatient care, using a mixed method approach.

INTRODUCTION: Despite the long-known significance of the nurse-patient relationship, research in psychiatric inpatient care still reports unfulfilled expectations of, and difficulties in, interactions and relationships between patients and staff. Interventions that create structures to allow quality interactions between patients and staff are needed to solve these problems. The aim of this project is to test effects of the nursing intervention Time Together and to evaluate the intervention process. METHODS AND ANALYSIS: This is a multisite study with a single-system experimental design using frequent measures. The primary outcomes are quality interactions for patients and perceived stress for staff. Secondary outcomes are levels of symptoms of anxiety and depression for patients and stress of conscience for staff. A process evaluation is performed to describe contextual factors and experiences. Data are collected using questionnaires, participant observations and semistructured interviews. For analysis of quantitative data, both visual and statistical methods will be used. Qualitative data will be analysed using qualitative content analysis. ETHICS AND DISSEMINATION: Ethical approval was granted by the Ethical Review Board in the region (Dnr 2016/339-31). The findings will contribute to the development of nursing interventions in general, but more specifically to the development of the intervention. This is relevant both nationally and internationally as similar interventions are needed but sparse. The findings will be disseminated through conference presentations and peer-reviewed publications. TRIAL REGISTRATION NUMBER: NCT02981563.

Does size really matter? A multisite study assessing the latent structure of the proposed ICD-11 and DSM-5 diagnostic criteria for PTSD.

Background: Researchers and clinicians within the field of trauma have to choose between different diagnostic descriptions of posttraumatic stress disorder (PTSD) in the DSM-5 and the proposed ICD-11. Several studies support different competing models of the PTSD structure according to both diagnostic systems; however, findings show that the choice of diagnostic systems can affect the estimated prevalence rates. Objectives: The present study aimed to investigate the potential impact of using a large (i.e. the DSM-5) compared to a small (i.e. the ICD-11) diagnostic description of PTSD. In other words, does the size of PTSD really matter? Methods: The aim was investigated by examining differences in diagnostic rates between the two diagnostic systems and independently examining the model fit of the competing DSM-5 and ICD-11 models of PTSD across three trauma samples: university students (N = 4213), chronic pain patients (N = 573), and military personnel (N = 118). Results: Diagnostic rates of PTSD were significantly lower according to the proposed ICD-11 criteria in the university sample, but no significant differences were found for chronic pain patients and military personnel. The proposed ICD-11 three-factor model provided the best fit of the tested ICD-11 models across all samples, whereas the DSM-5 seven-factor Hybrid model provided the best fit in the university and pain samples, and the DSM-5 six-factor Anhedonia model provided the best fit in the military sample of the tested DSM-5 models. Conclusions: The advantages and disadvantages of using a broad or narrow set of symptoms for PTSD can be debated, however, this study demonstrated that choice of diagnostic system may influence the estimated PTSD rates both qualitatively and quantitatively. In the current described diagnostic criteria only the ICD-11 model can reflect the configuration of symptoms satisfactorily. Thus, size does matter when assessing PTSD.

Planteamiento: Los investigadores y clínicos del campo del trauma pronto decidirán entre dos descripciones diagnósticas diferentes del trastorno de estrés postraumático (TEPT) en el DSM-5 y la propuesta CIE-11. Varios estudios apoyan diferentes modelos en competencia sobre la estructura del TEPT en función de ambos sistemas de diagnóstico; sin embargo, los resultados demuestran que la elección de los sistemas de diagnóstico puede afectar las tasas de prevalencia estimadas. Objetivos: y métodos. El presente estudio tenía como objetivo investigar el impacto potencial de usar una descripción del TEPT amplia (es decir, el DSM-5) en comparación con una pequeña (es decir, la CIE-11). En otras palabras, ¿el tamaño del TEPT importa realmente? El objetivo se investigó mediante el examen de las diferencias en las frecuencias de diagnóstico entre los dos sistemas de diagnóstico y examinando de forma independiente cómo se ajustaban los modelos en competencia para el TEPT del DSM-5 y la CIE-11 en tres muestras de trauma: estudiantes universitarios (N = 4213), pacientes con dolor crónico (N = 573) y personal militar (N = 118). Resultados: Las tasas diagnósticas del TEPT fueron significativamente más bajas según los criterios de la propuesta CIE-11 en la muestra universitaria, pero no se encontraron diferencias significativas para los pacientes con dolor crónico y el personal militar. El modelo de tres factores propuesto por la CIE-11 proporcionó el mejor ajuste de los modelos de la CIE-11 que fueron probados en todas las muestras. En cambio, el modelo híbrido de siete factores del DSM-5 proporcionó el mejor ajuste en las muestras universitaria y del dolor, y el modelo de Anhedonia de seis factores del DSM-5 en la muestra militar de los modelos probados del DSM-5. Conclusiones: Se pueden debatir las ventajas y desventajas de utilizar un conjunto amplio o reducido de síntomas para el TEPT; sin embargo, este estudio demostró que la elección del sistema de diagnóstico puede influir en las tasas estimadas del TEPT, tanto cualitativa como cuantitativamente. Al mismo tiempo, parece que, dados los criterios diagnósticos descritos actualmente, solo el modelo de la CIE-11 puede reflejar satisfactoriamente la configuración de los síntomas. Por lo tanto, el tamaño importa cuando se evalúa el TEPT.