S199. ENHANCED OLFACTORY IDENTIFICATION IN ADOLESCENTS WITH PSYCHOTIC EXPERIENCES

Abstract Background The olfactory system has a widely distributed anatomical network reaching both cortical and subcortical structures (Milardi et al., 2017). Olfactory dysfunction has been associated with schizophrenia (Moberg & Turetsky, 2003), where deficits in odour identification (Seidman et al., 1997), odor detection threshold sensitivity (Serby et al., 1990) and odour memory (Wu et al., 1993) can be seen early in the course of the disorder and persist with illness duration (Rupp, 2010). This olfactory dysfunction has been correlated with cognitive deficits, including language (Corcoran et al., 2005), verbal and non-verbal memory (Moberg et al., 2006) and tests of emotional recognition (Goudsmit et al., 2003) in schizophrenia. Neuroanatomically, areas of the temporal lobe, including the superior temporal gyrus, hippocampus and amygdala have all been implicated in the dysfunction. It is not known whether olfactory changes can be detected in the broader extended psychosis phenotype. Methods The current research focuses on a community-based sample of young adolescents aged 11–13 (N= 140) recruited from schools in the Dublin and Kildare areas of Ireland, These adolescents were assessed for psychotic symptoms using the psychosis section of the Schedule for Affective Disorders and Schizophrenia and also completed the Brief Smell Identification Test (BSIT), derived from the University of Pennsylvania Smell Identification Test (UPSIT),as part of a neuropsychological assessment. The BSIT is a self-administered 12-item test of olfactory functioning, containing common odours (eg lemon, chocolate, and smoke) and participants were required to choose one of four multiple-choice answers. Results Performance on the BSIT was compared between participants who reported any psychotic experiences (PE) (N=71), and those who did not (N=69). We examined total score and scores for individual smell types, using ANOVA, and co-varied for age and gender. Results A significant group difference was found when both age and gender were co-varied for, in which the PE group performed significantly better on the BSIT (F=5.56, p= 0.02), and one of the individual twelve odours (‘‘paint- thinner’’) of the BSIT also was significantly better identified by the PE group (F=7.53, p=0.007). When examined in terms of correlations with psychotic symptoms, BSIT scores were found to significantly correlate with Grandiosity, one of the eight categories of the Adolescent Psychotic-Like Symptoms Screener (APSS) (p=0.004). Discussion Moberg et al. (2013) report that positive symptoms of psychosis may be moderating our results, where it was hypothesized that this early olfactory hypersensitivity is due to increased vigilance of external and internal stimuli. Corcoran et al. (2005) similarly found that the presence of features associated with mania, such as grandiosity, was associated with better outcomes in smell identification tests. We hope to extend our analysis to search for neuroanatomical and neuropsychological correlates of these olfactory performance scores in young people with and without psychotic symptoms, as well as looking more in-depth at positive symptoms reported by the PE group and their possible associations with this increased hypersensitivity in olfactory identification. The current research is hoped to capture some of the earliest olfactory changes associated with psychosis vulnerability as a possible biomarker. The study employs a novel participant cohort whom are considered an extended psychosis phenotype and at this point only exhibit psychotic symptoms, but remain at an increased risk of the development of psychosis in adulthood.

Background: Schizophrenia is a highly heritable disease, mediated through a combination of common and rare genetic variants. In addition to genetic risk, several putative environmental risk factors have been studied in the context of schizophrenia. It has been suggested that the genetic effects on the etiology of schizophrenia may be of limited explanatory power if not viewed in the context of interaction with environmental stressors. Here, in a pre-adolescent population-based sample, we used polygenic risk scores from a case-control discovery sample of the Psychiatric Genomics Consortium as indicators of genetic vulnerability to schizophrenia. In addition, hair cortisol levels were obtained as a naturalistic quantitative metric of long-term physiological stress. We examined whether cortisol levels moderated the relationship between schizophrenia polygenic risks scores and pre-adolescent brain structure. Methods: This study was embedded in the Generation R Study, a prospective birth cohort from the Netherlands. Polygenic risk scores for schizophrenia were calculated in children of European ancestry only. P-value thresholds for inclusion of genetic variants in the polygenic risk score varied between P < 0.001 and P < 1. Hair cortisol was collected when the children were approximately 6 years old. At age 9 years, children underwent a magnetic resonance imaging (MRI) procedure to assess volumetric brain measures. After genetic and neuroimaging quality control procedures, the final sample consisted of 522 participants. Linear regression models were conducted to examine the associations between schizophrenia polygenic risk scores, hair cortisol levels, and brain volumes. All analyses were adjusted for age, sex, hair color, hair product use and four genetic principal components. Results: Schizophrenia polygenic risk scores were not associated with hair cortisol levels (P-value threshold [PT] < 0.001, β = -0.03, 95% confidence interval [CI] -0.11 -0.05, P = 0.441), cortical grey matter volume (PT < 0.001, β = -0.03, 95% CI -0.11 -0.05, P = 0.457) or cerebral white matter volume (PT < 0.001, β = -0.04, 95% CI -0.12 -0.04, P = 0.356). Higher schizophrenia polygenic risk scores were associated with lower total ventricle volume (PT <0.001, β = -0.10, 95% CI -0.19 --0.02, P = 0.022), including when mutually adjusted for total brain volume. Notably however, hair cortisol exhibited a positive interaction with schizophrenia risk scores in predicting total ventricle volume (PT < 0.001, β = 0.10, 95% CI 0.01 -0.18, P = 0.027), i.e. higher schizophrenia polygenic risk score and higher hair cortisol levels were associated with increased ventricle volumes. Hair cortisol was not independently associated with total ventricle volume (PT < 0.001, β = -0.05, 95% CI -0.14 -0.03, P = 0.215). Discussion: Elevated hair cortisol levels, a biological index of long-term stress, moderated the association between genetic vulnerability to schizophrenia and total cerebral ventricle volume among pre-adolescents. These findings underscore the importance of the interplay between genes and environment in shaping brain development. Using a polygenic risk score for schizophrenia, we provide novel, albeit preliminary, evidence for geneenvironment interaction between genetic risk for schizophrenia and environmental stressors in the general pre-adolescent population. This may help to elucidate underlying etiologies and possible early interventions for the psychosis spectrum.

Royal College of Surgeons in Ireland
Background: The olfactory system has a widely distributed anatomical network reaching both cortical and subcortical structures (Milardi et al., 2017). Olfactory dysfunction has been associated with schizophrenia (Moberg & Turetsky, 2003), where deficits in odour identification (Seidman et al., 1997), odor detection threshold sensitivity (Serby et al., 1990) and odour memory (Wu et al., 1993) can be seen early in the course of the disorder and persist with illness duration (Rupp, 2010). This olfactory dysfunction has been correlated with cognitive deficits, including language (Corcoran et al., 2005), verbal and non-verbal memory (Moberg et al., 2006) and tests of emotional recognition (Goudsmit et al., 2003) in schizophrenia. Neuroanatomically, areas of the temporal lobe, including the superior temporal gyrus, hippocampus and amygdala have all been implicated in the dysfunction. It is not known whether olfactory changes can be detected in the broader extended psychosis phenotype. Methods: The current research focuses on a community-based sample of young adolescents aged 11-13 (N= 140) recruited from schools in the Dublin and Kildare areas of Ireland, These adolescents were assessed for psychotic symptoms using the psychosis section of the Schedule for Affective Disorders and Schizophrenia and also completed the Brief Smell Identification Test (BSIT), derived from the University of Pennsylvania Smell Identification Test (UPSIT),as part of a neuropsychological assessment. The BSIT is a self-administered 12-item test of olfactory functioning, containing common odours (eg lemon, chocolate, and smoke) and participants were required to choose one of four multiple-choice answers. Results: Performance on the BSIT was compared between participants who reported any psychotic experiences (PE) (N=71), and those who did not (N=69). We examined total score and scores for individual smell types, using ANOVA, and co-varied for age and gender. Results: A significant group difference was found when both age and gender were co-varied for, in which the PE group performed significantly better on the BSIT (F=5.56, p= 0.02), and one of the individual twelve odours (''paint-thinner'') of the BSIT also was significantly better identified by the PE group (F=7.53, p=0.007). When examined in terms of correlations with psychotic symptoms, BSIT scores were found to significantly correlate with Grandiosity, one of the eight categories of the Adolescent Psychotic-Like Symptoms Screener (APSS) (p=0.004). Discussion: Moberg et al. (2013) report that positive symptoms of psychosis may be moderating our results, where it was hypothesized that this early olfactory hypersensitivity is due to increased vigilance of external and internal stimuli. Corcoran et al. (2005) similarly found that the presence of features associated with mania, such as grandiosity, was associated with better outcomes in smell identification tests. We hope to extend our analysis to search for neuroanatomical and neuropsychological correlates of these olfactory performance scores in young people with and without psychotic symptoms, as well as looking more indepth at positive symptoms reported by the PE group and their possible associations with this increased hypersensitivity in olfactory identification. The current research is hoped to capture some of the earliest olfactory changes associated with psychosis vulnerability as a possible biomarker. The study employs a novel participant cohort whom are considered an extended psychosis phenotype and at this point only exhibit psychotic symptoms, but remain at an increased risk of the development of psychosis in adulthood.

S200. HYPOVITAMINOSIS D IN SCHIZOPHRENIA: PREVALENCE AND ASSOCIATED CLINICAL CHARACTERISTICS
Rahma Nefzi* ,1 , Amine Larnaout 1 , Hanen Ben Ammar 1 , Emira Khelifa 1 , Amina Aissa 1 , Zouhaier El Hechmi 1 1 Razi Hospital Background: Schizophrenia is an invalid and severe neurodevelopmental disorder. The implication of vitamin D in the etiopathogenesis of schizophrenia shows through the activation of cellular and inflammatory pathways. It is especially vitamin D deficiency that has been associated with schizophrenia. It is within this framework that this study aims to explore the relationship between vitamin D levels and the clinical characteristics in a cohort of Tunisian patients with schizophrenia.

Methods:
A cross-sectional and retrospective descriptive study was conducted at the "F" psychiatry department at the Razi Hospital, Manouba over a twelve-month period from June 1st, 2015 to May 31st, 2016, including 80 patients with schizophrenia in period of clinical remission. The evaluation focused on sociodemographic and clinical characteristics. A dosage of vitamin D was performed. Results: The patients had an average age of 42.5 years and 70% were male. The average vitamine D level was 10,57ng/ml ±5,9. 49% of patients had vitamin D insufficiency (between 10 and 30 ng/ml) and 51% had vitamin D deficiency (<10 ng/ml). Vitamin D levels had not been affected by the clinical characteristics of the disease. A negative correlation with the total score of the negative scale (p <0.001) as well as with the severity item of the clinical global impression scale (p = 0.01) were found. Discussion: A large number of research studies in immunogenetics and molecular biology have highlighted the involvement of vitamin D in the etiopathogenesis of schizophrenia through its role in the ontogenesis of dopaminergic systems and also through its intervention in the processes of neuro-protection, immunomodulation and the reduction of oxidative stress. In addition, it has been established that people with psychotic disorders have a high prevalence of vitamin D deficiency, but the correlates and relevance of this deficiency remain unclear.

S201. RELATION BETWEEN PSYCHOTROPIC DRUGS AND SEIZURE THRESHOLD IN ELECTROCONVULSIVE THERAPY
Seung Hyun Kim* ,1 , Jung-Seo Yi 2 , Su-Hyuk Chi 3 , Hyun-Ghang Jeong 3 1 Korea University, Guro Hospital College of Medicine; 2 Hallym University College of Medicine, Kangnam Sacred Heart Hospital; 3 Korea University, Guro Hospital Background: Electroconvulsive therapy (ECT) is the most popular way to stimulate brain for achieving therapeutic effects. The therapeutic effect of ECT results from the induction of a generalized seizure. The minimal amount of electrical energy needed to induce seizures is known as the seizure threshold (ST). It is commonly believed that treatment efficacy is related to stimulus dose relative to ST, but higher stimuli usually also increase unwanted side effects. Therefore, ST is an important issue in conducting ECT. Most patients including schizophrenics undergoing ECT take concomitant psychotropic drugs, but little information is available on how these drugs affect ST. Our study aimed to analyze the relationship between ST and psychotropic drugs in patients treated with ECT. Methods: We retrospectively reviewed the medical charts of 43 patients who received ECT at Korea University Guro Hospital between February 2009 and June 2015. Patients with a history of seizure disorders or other medical emergent conditions were excluded. A total of fifty-eight subjects received ECT during the study period. Patients were excluded if treatment was aborted due to side effects or any other reasons before the 10th session (n=12) because we intended to investigate the ST shift during the course of consecutive ECT sessions. We included 43 subjects in the final data analysis. Patients' psychiatric disorders were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-R) by at least two experienced psychiatrists. ECT was administrated with concurrent antipsychotics and antidepressants.67.4 percent of subjects were diagnosed as schizophrenia and 20.9 percent of subjects were diagnosed as major depressive disorder. We used stepwise multivariate correlation analyses for examining the associations between ST and psychotropic drugs. Data are presented as initial ST, the difference in ST between the first and 10th sessions (ΔST10th), and the mean difference in ST between the first and last sessions (mean ΔSTlast). We used chlorpromazine-equivalent dose for antipsychotics and fluoxetine-equivalent dose for antidepressants.