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Abnormal effort-based decision-making represents a potential mechanism underlying motivational deficits (amotivation) in psychotic disorders. Previous research identified effort allocation impairment in chronic schizophrenia and focused mostly on physical effort modality. No study has investigated cognitive effort allocation in first-episode psychosis (FEP).
Cognitive effort allocation was examined in 40 FEP patients and 44 demographically-matched healthy controls, using Cognitive Effort-Discounting (COGED) paradigm which quantified participants’ willingness to expend cognitive effort in terms of explicit, continuous discounting of monetary rewards based on parametrically-varied cognitive demands (levels N of N-back task). Relationship between reward-discounting and amotivation was investigated. Group differences in reward-magnitude and effort-cost sensitivity, and differential associations of these sensitivity indices with amotivation were explored.
Patients displayed significantly greater reward-discounting than controls. In particular, such discounting was most pronounced in patients with high levels of amotivation even when N-back performance and reward base amount were taken into consideration. Moreover, patients exhibited reduced reward-benefit sensitivity and effort-cost sensitivity relative to controls, and that decreased sensitivity to reward-benefit but not effort-cost was correlated with diminished motivation. Reward-discounting and sensitivity indices were generally unrelated to other symptom dimensions, antipsychotic dose and cognitive deficits.
This study provides the first evidence of cognitive effort-based decision-making impairment in FEP, and indicates that decreased effort expenditure is associated with amotivation. Our findings further suggest that abnormal effort allocation and amotivation might primarily be related to blunted reward valuation. Prospective research is required to clarify the utility of effort-based measures in predicting amotivation and functional outcome in FEP.
The second Singapore Mental Health Study (SMHS) – a nationwide, cross-sectional, epidemiological survey - was initiated in 2016 with the intent of tracking the state of mental health of the general population in Singapore. The study employed the same methodology as the first survey initiated in 2010. The SMHS 2016 aimed to (i) establish the 12-month and lifetime prevalence and correlates of major depressive disorder (MDD), dysthymia, bipolar disorder, generalised anxiety disorder (GAD), obsessive compulsive disorder (OCD) and alcohol use disorder (AUD) (which included alcohol abuse and dependence) and (ii) compare the prevalence of these disorders with reference to data from the SMHS 2010.
Door-to-door household surveys were conducted with adult Singapore residents aged 18 years and above from 2016 to 2018 (n = 6126) which yielded a response rate of 69.0%. The subjects were randomly selected using a disproportionate stratified sampling method and assessed using World Health Organization Composite International Diagnostic Interview version 3.0 (WHO-CIDI 3.0). The diagnoses of lifetime and 12-month selected mental disorders including MDD, dysthymia, bipolar disorder, GAD, OCD, and AUD (alcohol abuse and alcohol dependence), were based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria.
The lifetime prevalence of at least one mood, anxiety or alcohol use disorder was 13.9% in the adult population. MDD had the highest lifetime prevalence (6.3%) followed by alcohol abuse (4.1%). The 12-month prevalence of any DSM-IV mental disorders was 6.5%. OCD had the highest 12-month prevalence (2.9%) followed by MDD (2.3%). Lifetime and 12-month prevalence of mental disorders assessed in SMHS 2016 (13.8% and 6.4%) was significantly higher than that in SMHS 2010 (12.0% and 4.4%). A significant increase was observed in the prevalence of lifetime GAD (0.9% to 1.6%) and alcohol abuse (3.1% to 4.1%). The 12-month prevalence of GAD (0.8% vs. 0.4%) and OCD (2.9% vs. 1.1%) was significantly higher in SMHS 2016 as compared to SMHS 2010.
The high prevalence of OCD and the increase across the two surveys needs to be tackled at a population level both in terms of creating awareness of the disorder and the need for early treatment. Youth emerge as a vulnerable group who are more likely to be associated with mental disorders and thus targeted interventions in this group with a focus on youth friendly and accessible care centres may lead to earlier detection and treatment of mental disorders.
This paper examines the effect of institutional contact on political participation among non-White communities. While both formal and informal institutions help shape community citizen participation, their effects vary on the historical inclusion (or exclusion) of certain racial groups. Formal institutions, like political parties, have historically excluded or neglected non-White and immigrant voters. We argue that for the excluded or neglected, non-traditional political institutions, like community based organizations, serve as supplements to facilitate political incorporation and engagement. These informal institutions help develop skills and resources among their constituents, and offer routine opportunities to participate. We use the 2008 Collaborative Multi-racial Post-Election Survey (CMPS) to test the differential effects of self-reported voter mobilization through nonpartisan and partisan institutional contact to explain variations among racial groups by the intensity of contact, occurrence of co-ethnic outreach, and type of institutional mobilization. We find that while contact by a partisan/political institution, like a political party or campaign, has an overall positive effect on political participation for all voters, contact by a nonpartisan/civic or community group is substantively more important for Latino and Asian American voter mobilization. Our analysis therefore offers cohesive evidence of how voters interact with and are affected by mobilization efforts that attends to differences across racial and ethnic boundaries, and variations in institutional contact.
Obesity and hyperglycaemia contribute to the atherosclerotic process in part through oxidative modifications to lipoprotein particles. The present study aimed to evaluate the effects of a lifestyle intervention on markers of oxidized lipoproteins in obese Latino adolescents with prediabetes.
Participants were enrolled into a 12-week lifestyle intervention. Measurements pre- and post-intervention included anthropometrics and body composition, lipid panel, oxidized LDL (oxLDL), oxidized HDL (oxHDL), intake of fresh fruits and vegetables, and cardiorespiratory fitness.
Thirty-five obese Latino adolescents (seventeen females, eighteen males; mean age 15·5 (sd 1·0) years; mean BMI percentile 98·5 (sd 1·2)) with prediabetes.
Intervention participation resulted in significant reductions in weight (−1·2 %, P = 0·042), BMI and BMI percentile (−2·0 and −0·4 %, respectively, P < 0·001), body fat (−7·0 %, P = 0·025), TAG (−11·8 %, P = 0·032), total cholesterol (−5·0 %, P = 0·002), VLDL-cholesterol (−12·5 %, P = 0·029), and non-HDL-cholesterol (−6·7 %, P = 0·007). Additionally, fitness (6·4 %, P < 0·001) and intake of fruits and vegetables (42·4 %, P = 0·025) increased significantly. OxLDL decreased significantly after the intervention (51·0 (sd 14·0) v. 48·7 (sd 12·8) U/l, P = 0·022), while oxHDL trended towards a significant increase (395·2 (sd 94·6) v. 416·1 (sd 98·4) ng/ml, P = 0·056).
These data support the utility of lifestyle intervention to improve the atherogenic phenotype of Latino adolescents who are at high risk for developing premature CVD and type 2 diabetes.
The Single Ventricle Reconstruction trial randomised neonates with hypoplastic left heart syndrome to a systemic-to-pulmonary-artery shunt strategy. Patients received care according to usual institutional practice. We analysed practice variation at the Stage II surgery to attempt to identify areas for decreased variation and process control improvement.
Prospectively collected data were available in the Single Ventricle Reconstruction public-use database. Practice variation across 14 centres was described for 397 patients who underwent Stage II surgery. Data are centre-level specific and reported as interquartile ranges across all centres, unless otherwise specified.
Preoperative Stage II median age and weight across centres were 5.4 months (interquartile range 4.9–5.7) and 5.7 kg (5.5–6.1), with 70% performed electively. Most patients had pre-Stage-II cardiac catheterisation (98.5–100%). Digoxin was used by 11/14 centres in 25% of patients (23–31%), and 81% had some oral feeds (68–84%). The majority of the centres (86%) performed a bidirectional Glenn versus hemi-Fontan. Median cardiopulmonary bypass time was 96 minutes (75–113). In aggregate, 26% of patients had deep hypothermic circulatory arrest >10 minutes. In 13/14 centres using deep hypothermic circulatory arrest, 12.5% of patients exceeded 10 minutes (8–32%). Seven centres extubated 5% of patients (2–40) in the operating room. Postoperatively, ICU length of stay was 4.8 days (4.0–5.3) and total length of stay was 7.5 days (6–10).
In the Single Ventricle Reconstruction Trial, practice varied widely among centres for nearly all perioperative factors surrounding Stage II. Further analysis may facilitate establishing best practices by identifying the impact of practice variation.
The quality of prenatal maternal mental health, from psychological stress and depressive symptoms to anxiety and other nonpsychotic mental disorders, profoundly affects fetal neurodevelopment. Despite the evidence for the influence of positive mental well-being on health, there is, to our knowledge, no research examining the possible effects of positive antenatal mental health on the development of the offspring. Using exploratory bifactor analysis, this prospective study (n = 1,066) demonstrated the feasibility of using common psychiatric screening tools to examine the effect of positive maternal mental health. Antenatal mental health was assessed during 26th week of pregnancy. The effects on offspring were assessed when the child was 12, 18, and 24 months old. Results showed that positive antenatal mental health was uniquely associated with the offspring's cognitive, language and parentally rated competences. This study shows that the effects of positive maternal mental health are likely to be specific and distinct from the sheer absence of symptoms of depression or anxiety.
To identify the common causal beliefs of mental illness in a multi-ethnic Southeast Asian community and describe the sociodemographic associations to said beliefs. The factor structure to the causal beliefs scale is explored. The causal beliefs relating to five different mental illnesses (alcohol abuse, depression, obsessive-compulsive disorder (OCD), dementia and schizophrenia) and desire for social distance are also investigated.
Data from 3006 participants from a nationwide vignette-based study on mental health literacy were analysed using factor analysis and multiple logistic regression to address the aims. Participants answered questions related to sociodemographic information, causal beliefs of mental illness and their desire for social distance towards those with mental illness.
Physical causes, psychosocial causes and personality causes were endorsed by the sample. Sociodemographic differences including ethnic, gender and age differences in causal beliefs were found in the sample. Differences in causal beliefs were shown across different mental illness vignettes though psychosocial causes was the most highly attributed cause across vignettes (endorsed by 97.9% of respondents), followed by personality causes (83.5%) and last, physical causes (37%). Physical causes were more likely to be endorsed for OCD, depression and schizophrenia. Psychosocial causes were less often endorsed for OCD. Personality causes were less endorsed for dementia but more associated with depression.
The factor structure of the causal beliefs scale is not entirely the same as that found in previous research. Further research on the causal beliefs endorsed by Southeast Asian communities should be conducted to investigate other potential causes such as biogenetic factors and spiritual/supernatural causes. Mental health awareness campaigns should address causes of mental illness as a topic. Lay beliefs in the different causes must be acknowledged and it would be beneficial for the public to be informed of the causes of some of the most common mental illnesses in order to encourage help-seeking and treatment compliance.
The ability to recognise a mental illness has important implications as it can aid in timely and appropriate help-seeking, and ultimately improve outcomes for people with mental illness. This study aims to explore the association between recognition and help-seeking preferences and stigmatising attitudes, for alcohol abuse, dementia, depression, obsessive-compulsive disorder (OCD) and schizophrenia, using a vignette-based approach.
This was a population-based, cross-sectional survey conducted among Singapore Residents (n = 3006) aged 18–65 years. All respondents were asked what they think is wrong with the person in the vignette and who they should seek help from. Respondents were also administered the Personal and Perceived sub scales of the Depression Stigma Scale and the Social Distance Scale. Weighted frequencies and percentages were calculated for categorical variables. A series of multiple logistic and linear regression models were performed separately by vignette to generate odd ratios and 95% confidence intervals for the relationship between help-seeking preference, and recognition and beta coefficients and 95% confidence intervals for the relationship between stigma and recognition.
Correct recognition was associated with less preference to seek help from family and friends for depression and schizophrenia. Recognition was also associated with increased odds of endorsing seeking help from a psychiatric hospital for dementia, depression and schizophrenia, while there was also an increased preference to seek help from a psychologist and psychiatrist for depression. Recognition was associated with less personal and perceived stigma for OCD and less personal stigma for schizophrenia, however, increased odds of social distancing for dementia.
The ability to correctly recognise a mental illness was associated with less preference to seek help from informal sources, whilst increased preference to seek help from mental health professionals and services and less personal and perceived stigma. These findings re-emphasise the need to improve mental health literacy and reinforce the potential benefits recognition can have to individuals and the wider community in Singapore.
The field of Developmental Origins of Health and Disease (DOHaD) seeks to understand the relationships between early-life environmental exposures and long-term health and disease. Until recently, the molecular mechanisms underlying these phenomena were poorly understood; however, epigenetics has been proposed to bridge the gap between the environment and phenotype. Epigenetics involves the study of heritable changes in gene expression, which occur without changes to the underlying DNA sequence. Different types of epigenetic modifications include DNA methylation, post-translational histone modifications and non-coding RNAs. Increasingly, changes to the epigenome have been associated with early-life exposures in both humans and animal models, offering both an explanation for how the environment may programme long-term health, as well as molecular changes that could be developed as biomarkers of exposure and/or future disease. As such, epigenetic studies in DOHaD hold much promise; however, there are a number of factors which should be considered when designing and interpreting such studies. These include the impact of the genome on the epigenome, the tissue-specificity of epigenetic marks, the stability (or lack thereof) of epigenetic changes over time and the importance of associating epigenetic changes with changes in transcription or translation to demonstrate functional consequences. In this review, we discuss each of these key concepts and provide practical strategies to mitigate some common pitfalls with the aim of providing a useful guide for future epigenetic studies in DOHaD.
In a time-lagged study with independent measures (N=115, paired responses), we examined the interactive effects of perceived organizational politics and overall satisfaction on job stress, interpersonal conflict, job performance, and creativity. The data were collected from a diverse sample of employees from various workplaces in Pakistan. The findings showed that perceived politics had a positive effect on job stress, while overall satisfaction had a negative effect on interpersonal conflict and a positive effect on creative performance. The results also revealed that in the face of high politics, highly satisfied individuals demonstrated higher levels of creativity and job performance. However, in this context of high politics negative effects were also observed, namely that highly satisfied individuals participated in interpersonal conflict and experienced high stress.
The current study aimed to: (i) describe the extent of overall stigma as well as the differences in stigma towards people with alcohol abuse, dementia, depression, schizophrenia and obsessive compulsive disorder, as well as (ii) establish the dimensions of stigma and examine its correlates, in the general population of Singapore, using a vignette approach.
Data for the current study came from a larger nation-wide cross-sectional study of mental health literacy conducted in Singapore. The study population comprised Singapore Residents (Singapore Citizens and Permanent Residents) aged 18–65 years who were living in Singapore at the time of the survey. All respondents were administered the Personal and Perceived scales of the Depression Stigma scale and the Social Distance scale to measure personal stigma and social distance, respectively. Weighted mean and standard error of the mean were calculated for continuous variables, and frequencies and percentages for categorical variables. Exploratory structural equation modelling and confirmatory factor analysis were used to establish the dimensions of stigma. Multivariable linear regressions were conducted to examine factors associated with each of the stigma scale scores.
The mean age of the respondents was 40.9 years and gender was equally represented (50.9% were males). The findings from the factor analysis revealed that personal stigma formed two distinct dimensions comprising ‘weak-not-sick’ and ‘dangerous/unpredictable’ while social distance stigma items loaded strongly into a single factor. Those of Malay and Indian ethnicity, lower education, lower income status and those who were administered the depression and alcohol abuse vignette were significantly associated with higher weak-not-sick scores. Those of Indian ethnicity, 6 years of education and below, lower income status and those who were administered the alcohol abuse vignette were significantly associated with higher dangerous/unpredictable scores. Those administered the alcohol abuse vignette were associated with higher social distance scores.
This population-wide study found significant stigma towards people with mental illness and identified specific groups who have more stigmatising attitudes. The study also found that having a friend or family member with similar problems was associated with having lower personal as well as social distance stigma. There is a need for well-planned and culturally relevant anti-stigma campaigns in this population that take into consideration the findings of this study.
A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.
Studies have suggested that maternal PUFA status during pregnancy may influence early childhood allergic diseases, although findings are inconsistent. We examined the relationship between maternal PUFA status and risk of allergic diseases in early childhood in an Asian cohort. Maternal plasma samples from the Growing Up in Singapore Towards Healthy Outcomes mother–offspring cohort were assayed at 26–28 weeks of gestation for relative abundance of PUFA. Offspring (n 960) were followed up from 3 weeks to 18 months of age, and clinical outcomes of potential allergic diseases (rhinitis, eczema and wheezing) were assessed by repeated questionnaires. Skin prick testing (SPT) was also performed at the age of 18 months. Any allergic disease with positive SPT was defined as having any one of the clinical outcomes plus a positive SPT. The prevalence of a positive SPT, rhinitis, eczema, wheezing and any allergic disease with positive SPT was 14·1 % (103/728), 26·5 % (214/808), 17·6 % (147/833), 10·9 % (94/859) and 9·4 % (62/657), respectively. After adjustment for confounders, maternal total n-3, n-6 PUFA status and the n-6:n-3 PUFA ratio were not significantly associated with offspring rhinitis, eczema, wheezing, a positive SPT and having any allergic disease with positive SPT in the offspring (P>0·01 for all). A weak trend of higher maternal n-3 PUFA being associated with higher risk of allergic diseases with positive SPT in offspring was observed. These findings do not support the hypothesis that the risk of early childhood allergic diseases is modified by variation in maternal n-3 and n-6 PUFA status during pregnancy in an Asian population.
Early life environments interact with genotype to determine stable phenotypic outcomes. Here we examined the influence of a variant in the brain-derived neurotropic factor (BDNF) gene (Val66Met), which underlies synaptic plasticity throughout the central nervous system, on the degree to which antenatal maternal anxiety associated with neonatal DNA methylation. We also examined the association between neonatal DNA methylation and brain substructure volume, as a function of BDNF genotype. Infant, but not maternal, BDNF genotype dramatically influences the association of antenatal anxiety on the epigenome at birth as well as that between the epigenome and neonatal brain structure. There was a greater impact of antenatal maternal anxiety on the DNA methylation of infants with the methionine (Met)/Met compared to both Met/valine (Val) and Val/Val genotypes. There were significantly more cytosine–phosphate–guanine sites where methylation levels covaried with right amygdala volume among Met/Met compared with both Met/Val and Val/Val carriers. In contrast, more cytosine–phosphate–guanine sites covaried with left hippocampus volume in Val/Val infants compared with infants of the Met/Val or Met/Met genotype. Thus, antenatal Maternal Anxiety × BDNF Val66Met Polymorphism interactions at the level of the epigenome are reflected differently in the structure of the amygdala and the hippocampus. These findings suggest that BDNF genotype regulates the sensitivity of the methylome to early environment and that differential susceptibility to specific environmental conditions may be both tissue and function specific.
Elucidating the cognitive architecture of schizophrenia promises to advance understanding of the clinical and biological substrates of the illness. Traditional cross-sectional neuropsychological approaches differentiate impaired from normal cognitive abilities but are limited in their ability to determine latent substructure. The current study examined the latent architecture of abnormal cognition in schizophrenia via a systematic approach.
Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were carried out on a large neuropsychological dataset including the Brief Assessment of Cognition in Schizophrenia, Continuous Performance Test, Wisconsin Card Sorting Test, Benton Judgment of Line Orientation Test, and Wechsler Abbreviated Scale of Intelligence matrix reasoning derived from 1012 English-speaking ethnic Chinese healthy controls and 707 schizophrenia cases recruited from in- and out-patient clinics.
An initial six-factor model fit cognitive data in healthy and schizophrenia subjects. Further modeling, which accounted for methodological variance between tests, resulted in a three-factor model of executive functioning, vigilance/speed of processing and memory that appeared to best discriminate schizophrenia cases from controls. Factor analytic-derived g estimands and conventionally calculated g showed similar case–control discrimination. However, agreement analysis suggested systematic differences between both g indices.
Factor structures derived in the current study were broadly similar to those reported previously. However, factor structures between schizophrenia subjects and healthy controls were different. Roles of factor analytic-derived g estimands and conventional composite score g were further discussed. Cognitive structures underlying cognitive deficits in schizophrenia may prove useful for interrogating biological substrates and enriching effect sizes for subsequent work.