Ruth E. Roberts

Postprandial plasma bile acid responses in normal weight and obese subjects

Background Bile acids can act as signalling molecules via various receptors including the nuclear farnesoid X receptor (FXR) and pregnane X receptor (PXR), and the cell surface G-protein-coupled receptor TGR5. The signalling has been implicated in the release of peptide YY (PYY) and glucagon-like peptide 1 (GLP-1), which improves glycaemic control and energy expenditure. We investigated whether morbidly obese subjects have altered postprandial bile acid responses in comparison to normal weight subjects. Method Blood samples were taken every 30 min from 0 to 180 min following a 400 kcal test meal. Samples were taken from 12 normal weight subjects with a body mass index (BMI) of 23.2 (2.8) kg/m2 (median [interquartile range (IQR)]) and seven obese patients with a BMI of 47.2 (7.2) kg/m2. Fractionated bile acids were measured on these samples using high-performance liquid chromatography tandem mass spectrometry. Results The obese subjects showed a lower postprandial response in total bile acids compared with the normal weight subjects. An increase of 6.4 (5.0) and 2.6 (3.3) μmol/L (median [IQR]) in normal weight and obese subjects was observed, respectively (P = 0.02). The difference was predominantly due to the glycine-conjugated fraction (P = 0.03). There was no difference in the increase of the unconjugated or taurine-conjugated fractions. Conclusions The decreased postprandial bile acid response in obese subjects compared with normal weight subjects may partly explain the suboptimal GLP-1 and PYY responses and could affect appetite, glycaemic control and energy expenditure.

The relationship between postprandial bile acid concentration, GLP-1, PYY and ghrelin

Background  Gut hormones peptide YY (PYY) and glucagon‐like peptide‐1 (GLP‐1) play an integral role in appetite control and energy homeostasis. Entero‐endocrine L‐cells can be stimulated by nutrients and or bile acids to co‐secrete PYY and GLP‐1. The aim of this study was to determine the response of bile acids, PYY, GLP‐1 and ghrelin after a test meal.

Daily stressors and negative life events in children at elevated risk of developing schizophrenia

BACKGROUND Psychological stress is implicated in the development of schizophrenia, but little is known about experiences of stress among children at elevated risk for the disorder. AIMS To examine stressor exposure and reactivity in children with different vulnerability profiles for schizophrenia: (a) children presenting multiple antecedents of schizophrenia (ASz group), (b) children with a family history of schizophrenia (FHx group) and (c) typically developing low-risk (TD) children. METHOD Ninety-five children (ASz = 29; FHx = 19; ASz+FHx = 5; TD = 42), identified aged 9-12 years using a community-based screening procedure or as relatives of individuals with schizophrenia, completed questionnaires assessing environmental stressors and psychopathology at age 11-14 years. RESULTS Relative to their typically developing peers, children in the FHx and ASz groups were exposed to a greater number of negative life events and a higher frequency of daily stressors, respectively; and were more distressed by these experiences. CONCLUSIONS Stress exposure and reactivity may constitute useful targets of early intervention for psychosis.

Mental health service use by young people: the role of caregiver characteristics.

Aims Many children and adolescents experiencing mental health problems do not receive appropriate care. Strategies to encourage appropriate access to services might be improved by a more detailed understanding of service use determinants within this group. In view of caregivers’ key role in young people’s pathways to care, this study aimed to advance understanding of caregiver-related characteristics that influence service use among young people. Methods We interviewed 407 primary caregivers of young people aged 9-18 years, recruited from a Greater London (United Kingdom) community sample. Caregivers reported on young people’s service use in health care sector and/or education settings, and caregivers’ intended stigmatising behaviours, help-seeking attitudes, and personal service use. Logistic regression analyses examined the relationship between these caregiver characteristics and young people’s service use, controlling for young people’s clinical and socio-demographic factors. Results Caregivers’ intended stigmatising behaviours in particular exerted a strong influence on young people’s service use within each service setting. The impact of this characteristic interacted with caregivers’ service use in influencing young people’s service use across health care and education settings and health care settings specifically. For young people’s service use within education settings, caregivers’ intended stigmatising behaviours score had a main effect. Conclusions This study highlights the key role caregivers’ attitudes and experiences hold in young people’s service use. The findings indicate that strategies aiming to bridge the gap between young people’s service needs and utilisation might be improved by targeting stigma amongst caregivers.

Connectomic markers of disease expression, genetic risk and resilience in bipolar disorder.

Bipolar disorder (BD) is characterized by emotional dysregulation and cognitive deficits associated with abnormal connectivity between subcortical—primarily emotional processing regions—and prefrontal regulatory areas. Given the significant contribution of genetic factors to BD, studies in unaffected first-degree relatives can identify neural mechanisms of genetic risk but also resilience, thus paving the way for preventive interventions. Dynamic causal modeling (DCM) and random-effects Bayesian model selection were used to define and assess connectomic phenotypes linked to facial affect processing and working memory in a demographically matched sample of first-degree relatives carefully selected for resilience (n=25), euthymic patients with BD (n=41) and unrelated healthy controls (n=46). During facial affect processing, patients and relatives showed similarly increased frontolimbic connectivity; resilient relatives, however, evidenced additional adaptive hyperconnectivity within the ventral visual stream. During working memory processing, patients displayed widespread hypoconnectivity within the corresponding network. In contrast, working memory network connectivity in resilient relatives was comparable to that of controls. Our results indicate that frontolimbic dysfunction during affect processing could represent a marker of genetic risk to BD, and diffuse hypoconnectivity within the working memory network a marker of disease expression. The association of hyperconnectivity within the affect-processing network with resilience to BD suggests adaptive plasticity that allows for compensatory changes and encourages further investigation of this phenotype in genetic and early intervention studies.

Pituitary gland volume and psychosocial stress among children at elevated risk for schizophrenia

BACKGROUND Pituitary volume enlargements have been observed among individuals with first-episode psychosis. These abnormalities are suggestive of hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, which may contribute to the development of psychosis. However, the extent to which these abnormalities characterize individuals at elevated risk for schizophrenia prior to illness onset is currently unclear, as volume increases, decreases and no volume differences have all been reported relative to controls. The current study aimed to determine whether antipsychotic-naive, putatively at-risk children who present multiple antecedents of schizophrenia (ASz) or a family history of illness (FHx) show pituitary volume abnormalities relative to typically developing (TD) children. An additional aim was to explore the association between pituitary volume and experiences of psychosocial stress. METHOD ASz (n = 30), FHx (n = 22) and TD (n = 32) children were identified at age 9-12 years using a novel community-screening procedure or as relatives of individuals with schizophrenia. Measures of pituitary volume and psychosocial stress were obtained at age 11-14 years. RESULTS Neither ASz nor FHx children showed differences in pituitary volume relative to TD children. Among FHx children only, pituitary volume was negatively associated with current distress relating to negative life events and exposure to physical punishment. CONCLUSIONS The lack of pituitary volume abnormalities among ASz and FHx children is consistent with our previous work demonstrating that these children are not characterized by elevated diurnal cortisol levels. The findings imply that these biological markers of HPA axis hyperactivity, observed in some older samples of high-risk individuals, may emerge later, more proximally to disease onset.

The relationship between salivary C-reactive protein and cognitive function in children aged 11–14 years: Does psychopathology have a moderating effect?

Highlights • Salivary CRP predicts poorer executive functioning in children aged 11–14 years.• The association is not confounded or moderated by concurrent psychopathology.• Findings have implications for interventions targeting cognitive deficits.• Salivary CRP can be used to investigate inflammation-brain function relationships.

T15. LONGITUDINAL ASSOCIATIONS BETWEEN CHILDHOOD SALIVARY CORTISOL LEVELS AND PRODROMAL SYMPTOMS IN LATE ADOLESCENCE: FINDINGS FROM A HIGH-RISK COHORT

Abstract Background Individuals with established psychosis are characterised by a distinct pattern of hypothalamic-pituitary-adrenal (HPA) axis dysfunctions which include both elevated daytime cortisol levels and a blunted cortisol awakening response (CAR). Whilst these patterns of dysfunction have also been observed among those at elevated risk for the disorder, longitudinal studies are scarce. As such, the relevance of these HPA axis abnormalities for the progression of psychopathology in high-risk populations is unknown. Utilising data from a well-characterised, longitudinal cohort of youth at elevated risk for schizophrenia and their typically-developing peers (The Child Health and Development Study), we aimed to investigate the extent to which HPA axis function determined in childhood is a significant predictor of putative prodromal status and psychopathology in late adolescence/early adulthood. Methods The sample comprised high-risk individuals who presented either multiple antecedents of schizophrenia (developmental delays, psychopathology, and psychotic-like experiences: ASz=21) or a family history of illness (FHx=13), and typically-developing youth with neither antecedents nor a family history (TD=36). Participants were recruited at age 9–12 years using a community screening method and assessed biennially throughout adolescence. At the age 11–14 years assessment phase, participants collected salivary cortisol samples in their home environment which were used to determine diurnal cortisol secretion and the CAR. At the age 17–21 years assessment phase, participants completed measures of prodromal symptoms (Prodromal Questionnaire: PQ), depression (Quick Inventory of Depressive Symptomatology questionnaire: QIDS), and anxiety (Social Interaction Anxiety Scale: SIAS). Established PQ thresholds were used to identify participants who met probable prodromal status. Logistic and linear regression analyses were used to examine the extent to which salivary cortisol measures at age 11–14 years predicted probable prodromal status and continuous psychopathology measures at 17–21 years, respectively. Results Relative to the TD group, ASz youth were characterised by higher depression (B=0.24, p=0.05) and disorganised symptoms (B=0.36, p=0.007) at 17–21 years whilst FHx youth obtained higher scores on the PQ general symptoms scale (B=0.24, p=0.048). Analyses performed in the total sample indicated that the CAR was negatively associated with depression symptoms (B=-0.28, p=0.006) and PQ negative symptoms (B=-0.30, p=0.004) at age 17–21 years. Positive associations were observed between diurnal cortisol and positive (B=0.41, p=0.02), disorganised (B=0.30, p=0.04), and general (B=0.29, p=0.03) PQ symptoms. Diurnal cortisol levels were also significantly associated with probable prodromal status at follow-up (OR=1.04, p=0.04). No significant interactions were observed between group status and salivary cortisol levels in any model. After adjustment for potential confounders (age, follow-up time, sex, BMI, and pubertal status), the CAR continued to show significant associations with both depression (p=0.006) and PQ negative symptoms (p=0.007) whilst only a statistical trend was observed for the relationship between diurnal cortisol levels and positive symptoms (p=0.055). Discussion The current study is the first to examine the extent to which HPA axis function can predict development of prodromal symptoms in a high-risk cohort. Our finding that more abnormal HPA axis function (i.e., a decreased CAR and higher diurnal cortisol) at age 11–14 years is associated with both prodromal and depression symptoms at age 17–21 has important implications for aetiological theories and for clinical practice.

Poster #S150 HYPOTHALAMIC-PITUITARY-ADRENAL AXIS DYSFUNCTION: AN EARLY MARKER OF PSYCHOSIS VULNERABILITY?

Abnormal hypothalamic-pituitary-adrenal (HPA) axis function, as indexed by elevated diurnal cortisol levels and a blunted cortisol awakening response (CAR), has been observed among patients with first- episode psychosis and also has been associated with neurocognitive deficits in this population . However, the extent to which HPA axis dysfunction precedes illness onset is currently unclear . Whilst elevated diurnal cortisol levels have been reported in samples of youth at ultra high-risk for psychosis, such elevations may relate to distress associated with emerging illness and might also be influenced by psychotropic medication . Further- more, studies of high-risk individuals with a family history of illness have typically included adult relatives who have passed the peak age of illness onset . As yet, no study of high-risk youth has examined the CAR or the extent to which HPA axis dysfunction is associated with neurocognitive performance . The current study aimed to determine whether children at putatively elevated risk for schizophrenia who present psychotic-like experiences and other antecedents of schizophrenia (ASz) and high-risk children with a family history of illness (FHx) are characterised by abnormal HPA axis function relative to their typically-developing (TD) peers . A further aim was to examine associations between HPA axis function and performance on tasks of memory and executive function among ASz and FHx children .