In search of disorders: internalizing symptom networks in a large clinical sample.

Background The co‐occurrence of internalizing disorders is a common form of psychiatric comorbidity, raising questions about the boundaries between these diagnostic categories. We employ network psychometrics in order to: (a) determine whether internalizing symptoms cluster in a manner reflecting DSM diagnostic criteria, (b) gauge how distinct these diagnostic clusters are and (c) examine whether this network structure changes from childhood to early and then late adolescence. Method Symptom‐level data were obtained for service users in publicly funded mental health services in England between 2011 and 2015 (N = 37,162). A symptom network (i.e. Gaussian graphical model) was estimated, and a community detection algorithm was used to explore the clustering of symptoms. Results The estimated network was densely connected and characterized by a multitude of weak associations between symptoms. Six communities of symptoms were identified; however, they were weakly demarcated. Two of these communities corresponded to social phobia and panic disorder, and four did not clearly correspond with DSM diagnostic categories. The network structure was largely consistent by sex and across three age groups (8–11, 12–14 and 15–18 years). Symptom connectivity in the two older age groups was significantly greater compared to the youngest group and there were differences in centrality across the age groups, highlighting the age‐specific relevance of certain symptoms. Conclusions These findings clearly demonstrate the interconnected nature of internalizing symptoms, challenging the view that such pathology takes the form of distinct disorders

Arterial blood pressure responses to short-term exposure to fine and ultrafine particles from indoor sources – A randomized sham-controlled exposure study of healthy volunteers

Objectives Particulate air pollution is linked to adverse cardiovascular effects. The aim of the study was to investigate the effect of short-term exposure to indoor particles on blood pressure (BP). Methods We analyzed the association of particle emissions from indoor sources (candle burning, toasting bread, frying sausages) with BP changes in 54 healthy volunteers in a randomized cross-over controlled exposure study. Particle mass concentration (PMC), size-specific particle number concentration (PNC) and lung-deposited particle surface area concentration (PSC) were measured during the 2 h exposure. Systolic and diastolic blood pressure were measured before, during, directly, 2, 4 and 24 h after exposure. We performed multiple mixed linear regression analyses of different particle metrics and BP. Results BP significantly increased with increasing PMC, PSC and PNC resulting from toasting bread. For example, an increase per 10 µg/m3 PM10 and PM2.5, systolic BP increased at all time points with largest changes 1 h after exposure initiation of 1.5 mmHg (95%-CI: 1.1; 1.9) and of 2.2 mmHg (95%-CI: 1.3; 3.1), respectively. Conclusions Our study suggests an association of short-term exposure to fine and ultrafine particles emitted from toasting bread with increases in BP. Particles emitted from frying sausages and candle burning did not consistently affect BP

Genetic probes of three theories of maternal adjustment: I. Recent evidence and a model

Studies focusing on genetic and social influences on maternal adjustment will illumine mother's marriage, parenting, and the development of psychopathology in her children. Recent behavioral genetic research suggests mechanisms by which genetic and social influences determine psychological development and adjustment. First, heritable, personal attributes may influence individuals' relationships with their family members. These genetically influenced family patterns may amplify the effects of adverse, heritable personal attributes on adjustment. Second, influences unique to siblings may be the most important environmental determinants of adjustment. We derive three hypotheses on maternal adjustment from integrating these findings from genetic studies with other contemporary research on maternal adjustment. First, mother's marriage mediates the influence of her heritable, personal attributes on her adjustment. Second, mother's recall of how she was parented is partially genetically influenced, and both her relationships with her spouse and her child mediate the impact of these genetically influenced representations on, her current adjustment. Third, characteristics of mother's spouse are important influences on difference between her adjustment and that of her sister's. These sibling-specific influences are unrelated to mother's heritable attributes. The current article develops this model, and the companion article describes the Twin Mom Study that was designed to test it as well, as its first findings. Data from this study can illumine the role of family process in the expression of genetic influence and lead to specific family interventions designed to offset adverse genetic influences