Richard P Ebstein

National University of Singapore | NUS · Department of Psychology

Babies of mothers who smoke during pregnancy tend to be born underweight but are at risk for pediatric obesity. Maternal feeding practices, maternal disordered eating, and child temperament were assessed as potential mediators of early weight gain in babies of smoking and non-smoking mothers. The BMIs of babies of 88 smoking and 107 non-smoking mot...

The herd instinct is a common feature of human society and is frequently encountered in a myriad of other human social interaction including entertainment, fashion, and the adoption of new gadgets. Indeed, social influence, taking account of others' actions in one's decisions, is ubiquitous in our daily life. With the growing prevalence of crowdfun...

Background: Whereas meditation training has been purported to support slower cellular aging, little work has explored the association among different facets of dispositional mindfulness, self-compassion, and cellular aging. The present study aimed to examine the relationship between leukocyte telomere length (LTL), an index of cellular aging, disp...

In a fast-changing world, creative thinking (CT) is an extraordinary currency. Oxytocin (OT) is associated with CT and release of OT depends on ADP ribosyl-cyclases ( CD38 and CD157 ). Moreover, CT as well as OT’s mechanism of action are mediated via central dopaminergic pathways. Consequently, we evaluate the roles of CD38 , CD157 , dopamine recep...

Background: Deficient extinction learning and threat adaptation in the ventromedial prefrontal cortex (vmPFC)-amygdala circuitry strongly impede the efficacy of exposure-based interventions in anxiety disorders. Recent animal models suggest a regulatory role of the renin-angiotensin system in both these processes. Against this background, the pres...

Background Early life stress has been associated with emotional dysregulations and altered architecture of limbic-prefrontal brain systems engaged in emotional processing. Serotonin regulates both, developmental and experience-dependent neuroplasticity in these circuits. Central serotonergic biosynthesis rates are regulated by Tryptophan hydroxylas...

In a rapidly greying world, the notion that some individuals maintain successful aging trajectories, viz. high physical, cognitive, emotional, and social functioning in older age, is increasingly germane. Biomarkers of such successful aging are increasingly sought. Leukocyte telomere length (LTL), an emerging yardstick of cellular aging that is inf...

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Sex hormones are significant regulators of stress reactivity, however, little is known about how genetic variation in hormone receptors contributes to this process. Here we report interactions between biological sex and repeat polymorphisms in genes encoding sex hormone receptors, and their effects on salivary cortisol reactivity in a sample of 100...

Objectives. The neuropeptide oxytocin regulates milk let-down during breastfeeding and maternal behavior in mammals. Oxytocin has also been shown to reduce stress through inhibitory effects on hypothalamic-pituitary-adrenal (HPA) reactivity. However, it remains unknown whether and how infant cortisol levels are affected by breastfeeding and what ro...

Background: Even before the onset of age-related diseases, obesity might be a contributing factor to the cumulative burden of oxidative stress and chronic inflammation throughout the life course. Obesity may therefore contribute to accelerated shortening of telomeres. Consequently, obese persons are more likely to have shorter telomeres, but the a...

This study explores the relationship between competitiveness and stress. In Experiment 1, we observe a higher response of cortisol—the primary stress hormone—to the computation task coupled with tournament than to the computation task with piece rate. Moreover, more competitive subjects exhibit higher stress responses than their less competitive co...

Oxytocin (OT) plays a salient role in contributing to the high levels of human sociality that characterize our species. Across the lifespan this nonapeptide promotes prosocial behaviors and modulates stress responses. Curiously, the OXT-Neurophysin I gene has been little studied despite the fact this is the structural gene for the OT nonapeptide. I...

Research has suggested that interpersonal touch promotes social processing and other-concern, and that women may respond to it more sensitively than men. In this study, we asked whether this phenomenon would extend to third-party observers who experience touch vicariously. In an eye-tracking experiment, participants (N = 64, 32 men and 32 women) vi...

Background Impairments in social behavior and cognition, such as the ability to identify others’ emotional state, are important features in schizophrenia. Arginine vasopressin (AVP) and oxytocin (OXT) and are nonapeptides that influence social cognition and behavior. Previous studies have shown that the administration of intranasal AVP or OXT may a...

Why some individuals seek social engagement while others shy away has profound implications for normal and pathological human behavior. Evidence suggests that oxytocin (OT), the paramount human social hormone, and CD38 that governs OT release, contribute to individual differences in social skills from intense social involvement to extreme avoidance...

Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASD) often co-occur. Both are highly heritable; however, it has been difficult to discover genetic risk variants. Glutamate and GABA are main excitatory and inhibitory neurotransmitters in the brain; their balance is essential for proper brain development and functioning...

Genome-wide association studies (GWAS) on Parkinson's disease (PD) have mostly been done in Europeans and Japanese. No study has been done in Han Chinese, which make up nearly a fifth of the world population. We conducted the first Han Chinese GWAS analyzing a total of 22,729 subjects (5,125 PD cases and 17,604 controls) from Singapore, Hong Kong,...

Killer-cell immunoglobulin-like receptors (KIRs) are a family of cell surface proteins found on natural killer cells, which are components of the innate immune system. KIRs recognize MHC class I proteins, mainly HLA-C and are further divided into two groups: short-tailed 2/3DS activating receptors and long-tailed 2/3DL inhibitory receptors. Based o...

This study explored the relationship between maternal touch and a child's spontaneous orienting towards social versus non-social information. Thirty-nine mothers and their 4-6 year old children participated in a 10-min play session. Following this session, children completed an object categorization task with face and house distractors. A social or...

Forty-five women participated in a variant of the social orienting paradigm employed in “Maternal Touch Predicts Attentional Bias Towards Faces in Young Children” (Reece, in press) [1]. On a given trial, they saw a mathematical equation and indicated whether this equation was true or false. Equations were superimposed on face or house distractors....

Background: Extranodal natural killer T-cell lymphoma (NKTCL), nasal type, is a rare and aggressive malignancy that occurs predominantly in Asian and Latin American populations. Although Epstein-Barr virus infection is a known risk factor, other risk factors and the pathogenesis of NKTCL are not well understood. We aimed to identify common genetic...

Although lying (bear false witness) is explicitly prohibited in the Decalogue and a focus of interest in philosophy and theology, more recently the behavioral and neural mechanisms of deception are gaining increasing attention from diverse fields especially economics, psychology and neuroscience. Despite the considerable role of heredity in explain...

Background: Polymorphisms in genes such as DAT1, 5HTTLPR, D4DR4 and MAO-A have been linked to Attention Deficit Hyperactivity Disorder (ADHD) and susceptibility for opiate addiction. We investigated in opiate addicted parents and their children the rate of ADHD and genetic markers that could predict susceptibility to ADHD and/or opiate addiction....

Primary angle closure glaucoma (PACG) is a major cause of blindness worldwide. We conducted a genome-wide association study (GWAS) followed by replication in a combined total of 10,503 PACG cases and 29,567 controls drawn from 24 countries across Asia, Australia, Europe, North America, and South America. We observed significant evidence of disease...

Significance This paper makes a singular contribution to understanding the association between biological aging indexed by leukocyte telomeres length (LTL) and delay discounting measured in an incentivized behavioral economic task. In a large group of young, healthy undergraduates, steeper delay discounting is significantly associated with shorter...

This study explores the relationship between competitiveness and stress. In Experiment 1, we examine the response of cortisol, the primary stress hormone, during both piece-rate and tournament tasks. We find that the more competitive tournament task induces a higher cortisol response than the less competitive piece-rate task. Moreover, more competi...

Assisted reproductive technologies (ART) lack biological filters that are part of the natural fertilization process and thus might enable the presence of abnormal genetic materials. Whereas the findings regarding neonatal and neurological risks among ART-conceived children are rather consistent, data regarding cognitive and social-emotional develop...

Objective: Oxytocin, a hypothalamic hormone secreted upon release of ectoenzyme CD38, plays a vital role in interpersonal bonding behaviors. Reduced plasma oxytocin characterizes autistic individuals. CD38 levels, which were found to be low in LBCs derived from autistic patients, is upregulated upon the addition of a vitamin A derivative. During p...

Intranasal administration of the neuropeptide oxytocin has been shown to influence a range of complex social cognitions and social behaviors, and it holds therapeutic potential for the treatment of mental disorders characterized by social functioning deficits such as autism, social phobia and borderline personality disorder. However, considerable v...

On a large sample of 2288 Han Chinese undergraduates, we investigated how religion and DRD4 are related to human altruistic giving behavior as measured with the Andreoni-Miller Dictator Game. This game enables us to clearly specify (non-)selfishness, efficiency, and fairness motives for sharing. Participants were further classified into religious c...

Significance Maternal care plays an important role in the development of the offspring’s social behaviors through the programming of relevant neural and hormonal systems. However, it is unclear how specific maternal behaviors, such as breastfeeding and genetic variation related to the oxytocin system, contribute to emerging social behaviors in huma...

Oxytocin (OT), a nonapeptide signaling molecule originating from an ancestral peptide, appears in different variants across all vertebrate and several invertebrate species. Throughout animal evolution, neuropeptidergic signaling has been adapted by organisms for regulating response to rapidly changing environments. The family of OT-like molecules a...

Given the moderate heritability of most complex traits, in which environment plays an important role, the sole pursuit of genetic markers alone may fail to reveal the fullness of phenotypic variance. A complimentary approach is to measure biomarkers in accessible tissues such as blood. Gene expression, which reflects both hereditable and environmen...

Autism spectrum disorders (ASD) is a complex disorder in which both genes and environmental factors play important roles. ASD is characterized by a high concordance rate in monozygotic twins pointing to high heritability for this disorder. Notably, the sibling recurrence risk ratio (λs) is 22 for autism. Despite the high heritability clinical sympt...

Twin and family studies suggest that political attitudes are partially determined by an individual's genotype. The dopamine D4 receptor gene (DRD4) exon III repeat region that has been extensively studied in connection with human behaviour, is a plausible candidate to contribute to individual differences in political attitudes. A first United State...

Fluency tests allow domain-specific assessment of verbal and non-verbal executive functions (EF) comparison and also enable utilizing of both quantitative and qualitative scoring methods. Thirty-five currently ill anorexia nervosa patients (PANs), 33 weight-restored patients (WRAN) and 47 healthy controls (HCs) were administered the word fluency te...

Affective knowledge, the ability to understand others' emotional states, is considered to be a fundamental part in efficient social interaction. Affective knowledge can be seen as related to cognitive empathy, and in the framework of theory of mind (ToM) as affective ToM. Previous studies found that cognitive empathy and ToM are heritable, yet litt...

IgA nephropathy (IgAN) is one of the most common primary glomerulonephritis. Previously identified genome-wide association study (GWAS) loci explain only a fraction of disease risk. To identify novel susceptibility loci in Han Chinese, we conduct a four-stage GWAS comprising 8,313 cases and 19,680 controls. Here, we show novel associations at ST6GA...

Genetic risk prediction has several potential applications in medical research and clinical practice and could be used, for example, to stratify a heterogeneous population of patients by their predicted genetic risk. However, for polygenic traits, such as psychiatric disorders, the accuracy of risk prediction is low. Here we use a multivariate line...

Genome-wide association studies (GWAS) of psychiatric disorders have identified multiple genetic associations with such disorders, but better methods are needed to derive the underlying biological mechanisms that these signals indicate. We sought to identify biological pathways in GWAS data from over 60,000 participants from the Psychiatric Genomic...

Empathy is the ability to recognize and share in the emotions of others. It can be considered a multi-faceted concept with cognitive and emotional aspects. Little is known regarding the underlying neurochemistry of empathy and in the current study we used a neurogenetic approach to explore possible brain neurotransmitter pathways contributing to co...

CD38, a transmembrane glycoprotein, which functions as an ectoenzyme with ADP-ribosyl cyclase activity, has been shown also to mediate the release of central oxytocin catalyzing an interest in the role of CD38 in behavior. A number of recent investigations have shown that CD38 is indeed associated with a variety of affiliative behaviors as would be...

This review examines evidence for the involvement of two nonapeptides, oxytocin (OT) and arginine vasopressin (AVP), in modulating the social and emotional brain in humans. We discuss research in nonclinical subjects before examining their role in various psychopathologies, mainly autism. We look at the effects of the intranasal administration of O...

In the first decade of consumer neuroscience, strong progress has been made in understanding how neuroscience can inform consumer decision making. Here, we sketch the development of this discipline and compare it to that of the adjacent field of neuroeconomics. We describe three new frontiers for ongoing progress at both theo-retical and applied le...

Significance Game theory is used throughout the social and biological sciences to study behavior in social interactions. Recent research suggests an important role for the dopamine neurotransmitter system in these types of decisions. This study used a competitive game to study how people varied in their decision-making processes and related these d...

Increasing evidence points to a role of dopaminergic pathways in modulating social behavior. Specifically, a polymorphic region in the third exon of the Dopamine D4 receptor (DRD4) has been associated with a host of social behaviors, often in an environment-sensitive manner. Empathy is thought to be an important motivator of prosocial behaviors and...

Purpose: Executive functions (EF) have been widely investigated in anorexia nervosa (AN) revealing difficulties in various aspects. We aimed at testing the effects of EF on stimuli perception and its representations in memory. Methods: Thirty AN underweight patients, 30 weight-restored AN patients, and 44 control participants, were recruited. Va...

Research indicates that risk for post-traumatic stress disorder (PTSD) is shaped by the interaction between genetic vulnerability and early caregiving experiences; yet, caregiving has typically been assessed by adult retrospective accounts. Here, we employed a prospective longitudinal design with real-time observations of early caregiving combined...

GPR88, coding for a G protein-coupled orphan receptor that is highly represented in the striatum, is a strong functional candidate gene for neuropsychiatric disorders and is located at 1p22-p21, a chromosomal region that we have previously linked to bipolar disorder (BD) in the Sardinian population. In order to ascertain the relevance of GPR88 as a...

Efforts have been made to characterize executive functions (EF) in anorexia nervosa (AN) both in the acute stage of the illness and after weight gain, yet many questions remain. The question of verbal versus visuo-perceptual stimuli in this regard has not been adequately addressed. The aim of this study is to further examine EF in women with past a...

This review represents not only an examination of the advances made in the last decade in the genetics of social cognition but most importantly, a roadmap for future progress in this emerging field. We discuss the evidence from twin studies that firmly establishes the relevancy of genetic hard wiring in the understanding of many social phenotypes w...

Haplotype analyses.

Linkage disequilibrium between paired SNP markers.

PCR primers and probes.

Our species, Homo sapiens, displays the most multifaceted social behaviour ever to evolve, far exceeding all other social species from eusocial insects to our nearest primate relatives. This intricate social behaviour underpins our remarkable success in evolving from cooperation in small bands of hunter gatherers �100000 yearsagoto the apex of glob...

Because multiple genes with small effect sizes are assumed to play a role in attention-deficit/hyperactivity disorder (ADHD) etiology, considering multiple variants within the same analysis likely increases the total explained phenotypic variance, thereby boosting the power of genetic studies. This study investigated whether pathway-based analysis...