Complex statistics in Hamiltonian barred galaxy models

We use probability density functions (pdfs) of sums of orbit coordinates, over time intervals of the order of one Hubble time, to distinguish weakly from strongly chaotic orbits in a barred galaxy model. We find that, in the weakly chaotic case, quasi-stationary states arise, whose pdfs are well approximated by $q$-Gaussian functions (with $1<q<3$), while strong chaos is identified by pdfs which quickly tend to Gaussians ($q=1$). Typical examples of weakly chaotic orbits are those that "stick" to islands of ordered motion. Their presence in rotating galaxy models has been investigated thoroughly in recent years due of their ability to support galaxy structures for relatively long time scales. In this paper, we demonstrate, on specific orbits of 2 and 3 degree of freedom barred galaxy models, that the proposed statistical approach can distinguish weakly from strongly chaotic motion accurately and efficiently, especially in cases where Lyapunov exponents and other local dynamic indicators appear to be inconclusive.Comment: 14 pages, 9 figures, submitted for publicatio

Wearable devices for assessing function in Alzheimer’s disease: a European public involvement activity about the features and preferences of patients and caregivers

Background: Alzheimer's Disease (AD) impairs the ability to carry out daily activities, reduces independence and quality of life and increases caregiver burden. Our understanding of functional decline has traditionally relied on reports by family and caregivers, which are subjective and vulnerable to recall bias. The Internet of Things (IoT) and wearable sensor technologies promise to provide objective, affordable, and reliable means for monitoring and understanding function. However, human factors for its acceptance are relatively unexplored. Objective: The Public Involvement (PI) activity presented in this paper aims to capture the preferences, priorities and concerns of people with AD and their caregivers for using monitoring wearables. Their feedback will drive device selection for clinical research, starting with the study of the RADAR-AD project. Method: The PI activity involved the Patient Advisory Board (PAB) of the RADAR-AD project, comprised of people with dementia across Europe and their caregivers (11 and 10, respectively). A set of four devices that optimally represent various combinations of aspects and features from the variety of currently available wearables (e.g., weight, size, comfort, battery life, screen types, water-resistance, and metrics) was presented and experienced hands-on. Afterwards, sets of cards were used to rate and rank devices and features and freely discuss preferences. Results: Overall, the PAB was willing to accept and incorporate devices into their daily lives. For the presented devices, the aspects most important to them included comfort, convenience and affordability. For devices in general, the features they prioritized were appearance/style, battery life and water resistance, followed by price, having an emergency button and a screen with metrics. The metrics valuable to them included activity levels and heart rate, followed by respiration rate, sleep quality and distance. Some concerns were the potential complexity, forgetting to charge the device, the potential stigma and data privacy. Conclusions: The PI activity explored the preferences, priorities and concerns of the PAB, a group of people with dementia and caregivers across Europe, regarding devices for monitoring function and decline, after a hands-on experience and explanation. They highlighted some expected aspects, metrics and features (e.g., comfort and convenience), but also some less expected (e.g., screen with metrics)

Does requiring trauma exposure affect rates of ICD-11 PTSD and complex PTSD? Implications for DSM-5

Objective: There is little evidence that posttraumatic stress disorder (PTSD) is more likely to follow traumatic events defined by Criterion A than non-Criterion A stressors. Criterion A events might have greater predictive validity for ICD-11 PTSD which is a condition more narrowly defined by core features. We evaluated the impact of using Criterion A, an ‘expanded’ trauma definition in line with ICD-11 guidelines, and no exposure criterion on rates of ICD-11 PTSD and Complex PTSD (CPTSD). We also assessed if five psychologically threatening events included in the expanded definition were as strongly associated with PTSD and CPTSD as ‘standard’ Criterion A events. Method: A nationally representative sample from Ireland (N = 1,020) completed self-report measures. Results: Most participants were trauma-exposed based on Criterion A (82%) and the ‘expanded’ (88%) criterion. When no exposure criterion was used, 13.7% met diagnostic requirements for PTSD or CPTSD; 13.2% when the expanded criterion was used, and 13.2% when Criterion A was used. The five psychologically threatening events were as strongly associated with PTSD and CPTSD as the Criterion A events. In a multivariate analysis, only the psychologically threatening events were significantly associated with PTSD (stalking) and CPTSD (bullying, emotional abuse, and neglect). Conclusions: Certain non-Criterion A events involving extreme fear and horror should be considered traumatic. The ICD-11 approach of providing clinical guidance rather than a formal definition offers a viable solution to some of the problems associated with the current and previous attempts to define traumatic exposure

The Need for Research on PTSD in Children and Adolescents: A commentary on Elliot et al., 2020

The recent release of the 11th version of The International Classification of Diseases (ICD?11: WHO, 2018) marked a significant departure from the previous similarities between it and the Diagnostic and Statistical Manual of Mental Disorders (DSM?5; APA, 2013) in terms of their conceptualization of posttraumatic stress disorder (PTSD). The ICD?11 proposed a reduced symptom set for PTSD and a sibling disorder called Complex PTSD. There have been numerous studies that have provided support for the integrity of, and distinction between, PTSD and CPTSD diagnoses in adult samples. Elliot and colleagues (2020) have added to the research literature by providing a valuable examination of the differences between ICD and DSM PTSD/CPTSD in a sample of youth aged 8 to 17 years. This commentary reviews this study and reflects on the need for greater understanding of developmental changes in the presentation of PTSD and Complex PTSD

ICD?11 Posttraumatic Stress Disorder and Complex Posttraumatic Stress Disorder in the United States: A Population?Based Study

The primary aim of this study was to provide an assessment of the current prevalence rates of ICD-11 posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD) among the adult population of the United States and to identify characteristics and correlates associated with each disorder. A total of 7.2% of the sample met criteria for either PTSD or CPTSD where the prevalence rate for PTSD was 3.4% and for CPTSD was 3.8%. Females were more likely than males to meet criteria for both PTSD and CPTSD. Cumulative adulthood trauma was associated with PTSD and CPTSD, however cumulative childhood trauma was more strongly associated with CPTSD than PTSD. Among traumatic stressors occurring in childhood, sexual and physical abuse by caregivers were identified as events associated with risk for CPTSD while sexual assault (by non-caregiver) and abduction were risk factors for PTSD. Adverse childhood events (ACEs) were associated with both PTSD and CPTSD and equally so. Those with CPTSD reported substantially higher psychiatric burden and lower psychological well-being compared to those with PTSD, and with neither diagnosis

Evidence for the coherence and integrity of the complex PTSD (CPTSD) diagnosis: response to Achterhof et al., (2019) and Ford (2020)

This letter to the editor responds to a recent EJPT editorial and following commentary which express concerns about the validity of the ICD-11 complex PTSD (CPTSD) diagnosis. Achterhof and colleagues caution that latent profile analyses and latent class analyses, which have been frequently used to demonstrate the discriminative validity of the ICD-11 PTSD and CPTSD constructs, have limitations and cannot be relied on to definitively determine the validity of the diagnosis. Ford takes a broader perspective and introduces the concept of ‘cPTSD’ which describes a wide ranging set of symptoms identified from studies related to DSM-IV, DSM-V and ICD-11 and proposes that the validity of the ICD-11 CPTSD is in question as it does not address the multiple symptoms identified from previous trauma-related disorders. We argue that ICD-11 CPTSD is a theory-driven, empirically supported construct that has internal consistency and conceptual coherence and that it need not explain nor resolve the inconsistencies of past formulations to demonstrate its validity. We do agree with Ford and with Achterhof and colleagues that no one single statistical process can definitively answer the question of whether CPTSD is a valid construct. We reference several studies utilizing many different statistical approaches implemented across several countries, the overwhelming majority of which have supported the validity of ICD-11 as a unique construct. We conclude with our own cautions about ICD-11 CPTSD research to date and identify important next steps

The role of negative cognitions, emotion regulation strategies, and attachment style in complex post-traumatic stress disorder: Implications for new and existing therapies

Objective We set out to investigate the association between negative trauma-related cognitions, emotional regulation strategies, and attachment style and Complex Posttraumatic Stress Disorder (CPTSD). As the evidence regarding the treatment of CPTSD is emerging, investigating psychological factors that are associated with CPTSD can inform the adaptation or the development of effective interventions for CPTSD. Method A cross sectional design was employed. Measures of CPTSD, negative trauma-related cognitions, emotion regulation strategies, and attachment style were completed by a British clinical sample of trauma-exposed patients (N = 171). Logistic regression analysis was used to assess the predictive utility of these psychological factors on diagnosis of CPTSD as compared to PTSD. Results It was found that the most important factor in the diagnosis of CPTSD was negative trauma-related cognitions about the self, followed by attachment anxiety, and expressive suppression. Conclusions Targeting negative thoughts and attachment representations while promoting skills acquisition in emotional regulation hold promise in the treatment of CPTSD. Further research is required on the development of appropriate models to treat CPTSD that tackle skills deficit in these areas

Validation of the International Trauma Interview (ITI) for the Clinical Assessment of ICD-11 Posttraumatic Stress Disorder (PTSD) and Complex PTSD (CPTSD) in a Lithuanian Sample

Background: The 11th revision of the International Classification of Diseases (ICD-11) includes a new diagnosis of complex posttraumatic stress disorder (CPTSD). The International Trauma Interview (ITI) is a novel clinician-administered diagnostic interview for the assessment of ICD-11 PTSD and CPTSD. Objective: The aim of this study was to evaluate the psychometric properties of the ITI in a Lithuanian sample in relation to interrater agreement, latent structure, internal reliability, as well as convergent and discriminant validity. Method: In total, 103 adults with a history of various traumatic experiences participated in the study. The sample was predominantly female (83.5%), with a mean age of 32.64 years (SD = 9.36). For the assessment of ICD-11 PTSD and CPTSD, the ITI and the self-report International Trauma Questionnaire (ITQ) were used. Mental health indicators, such as depression, anxiety, and dissociation, were measured using self-report questionnaires. The latent structure of the ITI was evaluated using confirmatory factor analysis (CFA). In order to test the convergent and discriminant validity of the ITI we conducted a structural equation model (SEM).Results: Overall, based on the ITI, 18.4% of participants fulfilled diagnostic criteria for PTSD and 21.4% for CPTSD. A second-order two-factor CFA model of the ITI PTSD and disturbances in self-organization (DSO) symptoms demonstrated a good fit. The associations with various mental health indicators supported the convergent and discriminant validity of the ITI. The clinician-administered ITI and self-report ITQ had poor to moderate diagnostic agreement across different symptom clusters. Conclusion: The ITI is a reliable and valid tool for assessing and diagnosing ICD-11 PTSD and CPTSD