Nature and nurture in suicidal behaviour; the role of genetics: Some novel findings

Abstract

Suicide affects about one million people each year, a phenomenon characterized by heterogeneous and complex causes. Often environmental factors such as negative life events may act as a significant contributor to suicidal behavior. However, in many cases the exposure to the same environmental stress does not result in increased suicidality. It is now well established that there is also a substantial genetic contribution to suicidal behavior. Our novel findings which need replication will be presented. We found that genetic variation in the noradrenergic tyrosine hydroxylase gene was associated with the angry/hostility personality trait and vulnerability to stress. Similarly, we recently discovered that genetic variation in the transcription factor T-box 19, an upstream regulator of the stress-related hypothalamic pituitary adrenocortical axis, showed significant linkage to a personality characterised by high anger/hostility in suicidal offspring. Further results from our studies have revealed that genetic variation in genes with roles in basal mechanisms of neural conduction, voltage-gated sodium channel type VIII alpha and vesicle-associated membrane 4 protein, showed association and linkage among suicide attempters. Additionally, we have results which give support to the findings of others, implicating the serotonin transporter and serotonin receptor 1A in suicidal behavior. Our future studies aim at identifying and resolving complex patterns and mechanisms of neurobiological gene-environment interactions, which may contribute to suicide.