Vulnerability biomarkers for mental illness and suicide risk: Regards for the development of pharmacological and psychological therapies

Abstract Background According to the diathesis-stress model, some individuals may have a certain underlying vulnerability (diathesis) that can be environmental or biological, such as a childhood trauma or a genetic predisposition. Hence, it is important to understand the epigenetic factors and the presence of biomarkers related to mental illness and suicide risk. Objective The present study aimed to evaluate if the presence of rs1800871 (IL- 10), rs2020933 (5-HTT) and rs1800629 (TNF – α) polymorphisms express different outcomes in terms of physical, psychological health and quality of life, considering the relations among them and the social environment, through observation of the psychological, physical, environment domains and the quality of social relations. Method A multivariate analysis (MANOVA) of the data was conducted, in which 481 participants were assessed through the instruments Quality of Life Brief Questionnaire (QOL – brief), Beck's Scale of Suicide Ideation (BSI) and the Mini International Neuropsychiatric Interview (MINI 5.5.0). The participants´ DNA was collected through a saliva sample of the oral mucosa. From the studied sample, 306 participants had mental disorder (MD) with no history of suicide attempt (HSA), 145 showed MD with HSA and 175 participants. Results A statistically significant difference (0.001 and 0.004) was found in the interaction of two factors, namely the social relationships domain and the presence of the IL- 10 polymorphism, leading to increased suicide risk and lower levels of quality of life in the physical domain. The interaction between the rs1800871 (IL-10) polymorphism and lower levels of quality of life in the environment and social environment domains appears to be related to a worse perception of physical health and a higher risk of suicide, which highlights the epigenetic influence for both physical and mental illness.