Intermediate Phenotypes in Suicidal Behavior Focus on Personality

Every year over 1 million people commit and over 10 million people attempt suicide. This is one suicide every 40s and one suicide attempt every 3s worldwide. Suicide accounts for almost 2% of the world’s death and it has emerged as one of the leading causes of death among individuals aged 15–34 years in most of the countries (Bertolote, 2001; Cantor, 2000; WHO, 2011). Attempted suicide is currently regarded as the most important predictor of a future death from suicide (Gunnell and Lewis, 2005). Almost one-quarter of suicides are preceded by nonfatal suicidal behaviors in the previous year (Owens and House, 1994) and ~2% of suicide attempters end their own life during the 12 months subsequent to the index event (Owens et al., 2002). In the years following an initial suicide attempt, studies indicate a suicide risk ranging from 3.2% (Suokas and Lonnqvist, 1991) to 11.6% (Nielsen et al., 1995) within 5 years, 4.8% (Beck and Steer, 1989) to 12.1% (Nielsen et al., 1995) within 10 years, 6.7% within 18 years (De Moore and Robertson, 1996), and 10%–15% within lifetime (Suominen et al., 2004).Suicidal behavior is complex and frequently classified by differentiating between suicidal ideation, suicide attempts, and completed suicide. It is not attributable only to one single cause but is a consequence of complex interactions of several risk factors like, for example, medical (e.g., mental disorders and chronic pain), psychological (e.g., hopelessness and aggressiveness), psychosocial (e.g., social isolation), social (e.g., lack of social support), cultural (e.g., religion), socioeconomic (e.g., unemployment), and biological (e.g. genetics and disorders in brain functioning).Early work especially focusing on demographic, psychiatric, and psychological factors found, among others, that being younger, unmarried, unemployed, having a psychiatric illness, feeling hopeless, and having recently experienced a stressful life event were directly correlated with an increased risk of suicide and suicidal behaviors, whereas religiousness, spirituality, and social support were found to have a protective effect. Furthermore, it was reported that being female was associated with a higher risk of suicidal attempt whereas being male was related to a greater risk of death associated to suicide (Nock et al., 2008). Beside all other risk factors, especially personality seems to have a high impact on suicidal behavior (Brezo et al., 2006).