European Psychiatry - Volume 41 - April 2017

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S166 25th European Congress of Psychiatry / European Psychiatry 41S (2017) S106–S169
Conclusions The present data suggest that the psychosocial stress
response is a multidimensional physiological event that is affected
by a variety of factors as diverse as 5-HTTLPR genotype, personality
profile, BMI, and age.
Disclosure of interest The authors have not supplied their decla-
ration of competing interest.
EW0181
Skin conductance response to
emotional stimuli and injury location
in patients with single right
hemisphere damage
S. Álvarez , G. Lahera ∗
1 Foundation Alicia Koplowitz Research Fellow, New York University
Child Study Center, Child Psychiatry, NY, USA
2 Psychiatry, University of Alcalá, Alcalá de Henares, Madrid, Spain
3 Cibersam, Mental Health, Madrid, Spain
∗ Corresponding author.
Introduction Right hemisphere damage (RHD) has been related
to alterations in emotion processing. However, results regarding
physiological responses are limited and inconsistent. More
research regarding specific brain areas involved in emotional phys-
iological responses is needed.
Objectives To examine the skin conductance response (SCR) to
emotion eliciting images in patients with single RHD. To explore
the relationship between SCR and brain injury location in patients
with single RHD.
Aims To examine the relationship between SCR and cortical and
subcortical damage in RH regarding emotional processing.
Method Forty-one individuals with RHD due to stroke were
assessed (mean age 68.5, SD 12.2, 51.1 males). The amplitude of
event-related SCR was registered through a biofeedback system
while observing 54 photographs from the international affective
picture system (IAPS). Emotional images were classified using
two different approaches: emotional valence (pleasant, unpleasant,
neutral) and social vs. non-social content. Brain damage location,
determined through medical records, included cortical (frontal,
parietal, temporal and occipital lobes) as well as sub-cortical (cau-
date nucleus, thalamus, lenticular nucleus, insular cortex, basal
ganglia and limbic system) structures.
Results Amplitude of SCR to emotional images was significantly
lower in individuals with occipital cortex injury compared to those
with damage in other brain locations ( P < 0.05). These results were
consistent through all stimuli categories but non-social pictures,
which presented the same pattern though, did not reach statistical
significance.
Conclusions Results show a relationship between occipital areas
in HD and SCR to emotional eliciting stimuli, suggesting occipital
right lobe involvement in physiological emotional processing.
Disclosure of interest The authors have not supplied their decla-
ration of competing interest.
EW0182
The use of polygenic risk scores to
inform aetiology of mood and
psychotic disorders
J. Harrison ∗, S. Mistry
Cardiff University School of Medicine, MRC Centre for
Neuropsychiatric Genetics and Genomics, Cardiff, Wales, United
Kingdom
∗ Corresponding author.
Introduction Polygenic risk scores (PRS) incorporate many small
geneticmarkers that are associatedwith conditions. This technique
was first used to investigate mental illnesses in 2009. Since then, it
has been widely used.
Objectives We wanted to explore how PRS have been used to the
study the aetiology of psychosis, schizophrenia, bipolar disorder
and depression.
Aims We aimed to conduct a systematic review, identify-
ing studies that have examined associations between PRS for
bipolar disorder, schizophrenia/psychosis and depression and
psychopathology-related outcome measures.
Methods We searched EMBASE, Medline and PsychInfo from
06/08/2009 to 14/03/2016. We hand-searched the reference lists
of related papers.
Results After removing duplicates, the search yielded 1043 pub-
lications. When irrelevant articles were excluded, 33 articles
remained. We found 24 studies using schizophrenia PRS, three
using bipolar PRS and nine using depression PRS. Many studies
successfully used PRS to predict case/control status. Some studies
showed associations between PRS and diagnostic sub-categories.
A range of clinical phenotypes and symptoms has been explored.
For example, specific PRS are associated with cognitive perfor-
mance in schizophrenia, psychotic symptoms in bipolar disorder,
and frequency of episodes of depression. PRS have also demon-
strated genetic overlap between mental illnesses. It was difficult
to assess the quality of some studies as not all reported sufficient
methodological detail.
Conclusions PRS have enabled us to explore the polygenic archi-
tecture of mental illness and demonstrate a genetic basis for some
observed features. However, they have yet to give insights into the
biology, which underpin mental illnesses.
Disclosure of interest The authors have not supplied their decla-
ration of competing interest.
EW0183
Identification of biological pathways
to Alzheimer’s disease using polygenic
scores
J. Harrison ∗ aker , L. Hubbard , D. Linden , J. Williams ,
V. Escott-Price , P. Holmans
Cardiff University School of Medicine, MRC Centre for
Neuropsychiatric Genetics and Genomics, Cardiff, Wales, United
Kingdom
∗ Corresponding author.
Introduction Single nucleotide polymorphisms (SNPs) contribute
small increases in risk for late-onset Alzheimer’s disease (LOAD).
LOAD SNPs cluster around genes with similar biological functions
(pathways). Polygenic risk scores (PRS) aggregate the effect of SNPs
genome-wide. However, this approachhas not beenwidely used for
SNPs within specific pathways.
Objectives We investigated whether pathway-specific PRS were
significant predictors of LOAD case/control status.
Methods We mapped SNPs to genes within 8 pathways impli-
cated in LOAD. For our polygenic analysis, the discovery sample
comprised 13,831 LOAD cases and 29,877 controls. LOAD risk
alleles for SNPs in our 8 pathways were identified at a P-
value threshold of 0.5. Pathway-specific PRS were calculated in
a target sample of 3332 cases and 9832 controls. The genetic
data were pruned with R 2 > 0.2 while retaining the SNPs most
significantly associated with AD. We tested whether pathway-
specific PRS were associated with LOAD using logistic regression,
adjusting for age, sex, country, and principal components. We
report the proportion of variance in liability explained by each
pathway.
Results Themost strongly associated pathwayswere the immune
response (NSNPs = 9304, = 5.63 × 10− 19, R2 = 0.04) and hemostasis
(NSNPs = 7832, P = 5.47× 10−7, R 2 = 0.015). Regulation of endocyto-
sis, hematopoietic cell lineage, cholesterol transport, clathrin and