Poster Index

Neurobiological underpinnings of suicidal behavior

Clinical and neurocognitive studies of suicidal behavior (17)  |  Clinical phenotyping of suicidal individuals (23)
Culture, ethnicity and spiritual approaches. New paradigms in suicidology (11)  |  Ethical and methodological challenges and solutions in suicide research (5)
Genetic, epigenetic and gene expression contributors to suicide risk (2)  |  Intervention research for prevention of suicidal behavior (30)
Lifespan differential aspects (from infancy to elderly) (7)  |  Miscellany (assisted suicide, minorities, legal aspects, etc.) (9)
Neurobiological underpinnings of suicidal behavior (3)  |  Novel monitoring strategies for detecting changes in risk over time (4)
Psychosocial variables: protective and risk factors. Resilience & vulnerability (38)  |  Testing the effectiveness of prevention strategies (6)




Neurobiological underpinnings of suicidal behavior


(90) PO-90. Trait impulsivity and interactions between phenylalanine/tyrosine ratio and Toxoplasma gondii seropositivity in healthy adults

Day: 10 | Time: 13:30 | Room: Poster Hall

Topic: Neurobiological underpinnings of suicidal behavior

Authors:Nadine Postolache . Department of Psychiatry, University of Maryland-Baltimore School of Medicine, Baltimore, MD, USA, Austria
- Thomas B. Cook - Lisa A. Brenner - Lena Brundin - Ashwin J. Matthai - Ina Giegling - Bettina Konte - Dietmar Fuchs - Dan Rujescu - Teodor T. Postolache -

 Introduction:
Suicidal behavior has been linked to Toxoplasma gondii (T. gondii) seropositivity (Pedersen et al., 2012). We previously found that T. gondii positive had higher scores of trait impulsivity (an intermediate phenotype for suicidal behavior (Mann et al., 2009) than T. gondii negative males (Cook et al., 2015). Impulsivity has been previously associated to dopamine function (Norbury and Husain, 2015); T. gondii is genetically endowed to synthesize dopamine (Gaskell et al., 2009), and the ratio of phenylalanine/ tyrosine (Phe/Tyr, precursors of dopamine) is affected by immune activation (necessary to keep T. gondii in check)
 Goals:
We sought to determine interactions between plasma levels of precursors of dopamine (phenylalanine and tyrosine) and T. gondii seropositivity in association to impulsivity.
 Methodology:
1,000 individuals with no psychiatric conditions by SCID for DSM-IV (510 men, 490 women, mean age 53.6 ± 15.8) self-rated impulsivity using the Zuckerman?s Sensation Seeking Scale (SSS-V). Plasma IgG antibodies to T. gondii were measured using ELISA and dopamine precursors with HPLC.
 Results:
Only among T. gondii positive males higher Phe:Tyr ratios were associated with increased impulsivity. Specifically, among IgG-positive males, compared to the lowest quartile of Phe:Tyr, males in upper quartile of Phe:Tyr scored higher (p = .006) on impulsivity. By contrast, higher Phe:Tyr ratios were not related to impulsivity in females or T.gondii-negative males.
 Conclusions:
Gender-specific interactions between metabolic changes in dopamine precursors, often altered by inflammation, and T. gondii seropositivity, could improve stratification of risk, and identify intersections of modifiable risk factors and lead to novel treatment targets for impulsivity and self-directed violence.
 References:
Pedersen M, et al. Toxoplasma gondii infection and self-directed violence in mothers. JAMA Psychiatry. 2012; 69: 1123-1130.
Mann J, et al. Candidate endophenotypes for genetic studies of suicidal behavior. Biol Psychiatry. 2009; 65: 556-563
Cook T, et al. Latent infection with Toxoplasma gondii: Association with trait aggression and impulsivity in healthy adults. J Psychiatr Res. 2015; 60: 87-94.
Norbury A, Husain M. Sensation-seeking: Dopaminergic modulation and risk for psychopathology. Behav Brain Res. 2015; 288: 79-93
Gaskell EA, et al. A unique dual activity amino acid hydroxylase in Toxoplasma gondii. PLoS One. 2009; 4:e4801


(323) PO-323. Inflammatory and metabolic biomarkers and history of suicide attempts in patients with schizophrenia

Day: 10 | Time: 13:30 | Room: Poster Hall

Topic: Neurobiological underpinnings of suicidal behavior

Authors:Leticia González-Blanco . Department of Psychiatry, University of Oviedo - Servicio de Salud del Principado de Asturias, Oviedo - SPAIN
- María Paz García-Portilla - Leticia García-Álvarez - Celso Iglesias - Lorena De La Fuente-Tomás - Pilar Alejandra Saiz - Ana Coto - Julio Bobes -

 Introduction:
Low lipid levels related to suicidality have been reported(1), and specifically in patients with schizophrenia(2). Pro-inflammatory and oxidative stress biomarkers have been described in suicidal patients as well(3,4).
 Goals:
To determinate potential inflammatory/metabolic biomarkers in patients with schizophrenia who have a history of suicide attempts (SA).
 Methodology:
Sample: 73 outpatients with schizophrenia, lenght of illness <11 years, under stable maintenance treatment [mean age(32.16), males(63.9%)] Evaluation: PANSS, Clinical Assessment Interview for Negative Symptoms (CAINS), Calgary Depression Scale (CDS). Biomarkers: C-Reactive Protein (CRP), Homocysteine, Lipoperoxidation subproducts, Glucose, Insulin, Cholesterol, HDL, LDL, Triglycerids, TSH.
 Results:
Partial correlations, after controlling BMI (28.8 kg/m2) and smoking (47.9%-smokers), found significant relationship (p<0.05) between number of SA and age (r=0.26), PANSS Total (r=0.28), Positive (r=0.46) and General (r=0.30) subscales and CDS (r=0.42) scores, HDL-cholesterol (r=0.29) and Insulin (r= -0.32). No inflammatory or oxidative biomarker showed any significant correlation. Subgroup analyses were performed [(a) patients taken Olanzapine, Clozapine or Quetiapine vs (b) other antipsychotics]: (a) correlation with HDL-cholesterol (r=0.29,p=0.062), Triglycerids (r=-0.38,p=0.066) and Insulin (r=-0.46,p=0.043); and (b) correlation with HDL-cholesterol (r=0.29,p=0.062) and TSH (r=0.37,p=0.017) were found. We performed a MANCOVA (Multivariate analysis of Covariate) to determinate differences in these parameters between patients with a history of SA (n=15; 20.5%) and patients without SA. PANSS Total, Positive and General Subscales, and CDS showed significantly higher scores in SA group (p<0.05). Insulin presented lower levels in SA group [10.2 vs 18.1mg/dl; F=4.60(p=0.036)]. No significant differences in age, HDL, Triglycerids and TSH between groups were found.
 Conclusions:
1. No inflammatory or oxidative biomarker was associated with a history of SA in patients with schizophrenia in our sample. 2. Lower Insulin concentrations was associated with a history of SA, but not lipid levels. However, HDL-Cholesterol had a positive relationship with number of SA.
 References:
(1) Wu S, Ding Y, Wu F, Xie G, Hou J, Mao P. Serum lipid levels and suicidality: a meta-analysis of 65 epidemiological studies. Journal of Psychiatry & Neuroscience. 2016; 41(1): 56–69. (2) Ainiyet B, Rybakowski JK. Suicidal Behavior in Schizophrenia may be Related to Low Lipid Levels. Medical Science Monitor: International Medical Journal of Experimental and Clinical Research. 2014; 20: 1486–1490. (3) Miná V, Lacerda-Pinheiro SF, Maia LC, Pinheiro R, Meireles CB, et al. The influence of inflammatory cytokines in physiopathology of suicidal behavior. Journal of Affective Disorders. 2015; 172: 219-230. (4) Vargas H, Vargas SO, Pizzo de Castro M, Bortolasci C, Barbosa D, Morimoto H, et al. Oxidative stress and lowered total antioxidant status are associated with a history of suicide attempts. Journal of Affective Disorders. 2016; 150(3): 923–930.


(352) PO-352. Relationship between inflammatory markers and sensitivity to social exclusion in vulnerability to depression and suicide

Day: 09 | Time: 13:30 | Room: Poster Hall

Topic: Neurobiological underpinnings of suicidal behavior

Authors:Ismael Conejero . Department of Emergency Psychiatry and Post Acute Care, Hôpital Lapeyronie, CHU Montpellier, Montpellier- France
- Emilie Olié -

 Introduction:
By the year 2020, depression is projected to reach the second place in the ranking of disability. Depression is highly associated with suicidal issue. On the one hand, evidence has reported a possible relationship between inflammatory processes, depression and suicide. On the other hand, social exclusion, frequent trigger of suicidal act, has been associated with inflammatory responses and prefrontal cerebral activations in healthy subjects.
 Goals:
The primary aim of our study is to measure the association between cerebral activations during social exclusion and levels of inflammatory markers in a clinical sample with vulnerability to depression while taking into account suicidal history.
 Methodology:
116 euthymic females aged 18 to 50 were included and clustered into 3 groups : 45 having a history of depression and suicide attempt, 43 having a history of depression without suicide attempt and 28 healthy subjects. During functional MRI, they performed Cyberball game, a validated social exclusion task . Blood levels of cytokines IL-1B, IL-6,TNFa and CRP were measured prior to MRI.
 Results:
We expect a positive correlation between levels of peripheral inflammatory markers and activations of anterior cingulate cortex and anterior insula in subjects with history of depressive disorder and suicide attempts.
 Conclusions:
Our results may help to better understand the role of inflammation in social stress and its role in emergence of depression and suicidal act.
 References:
1. Eisenberger NI. The pain of social disconnection: examining the shared neural underpinnings of physical and social pain. Nat Rev Neurosci [Internet]. 3 mai 2012 [cité 11 avr 2016]; Disponible sur: http://www.nature.com/doifinder/10.1038/nrn3231
2. Bowlby J. Attachment and loss: Retrospect and prospect. Am J Orthopsychiatry. 1982;52(4):664‑78.