Personality traits are influenced in part by one’s genetic make-up, with around 50% of their variation being genetic (Bouchard and Loehlin 2001). They are related to health and other life characteristics, and predict many aspects of psychiatric illness. In particular, neuroticism is associated with anxiety and depression (Brandes and Bienvenu 2006). Therefore, a better understanding of the genetic basis of psychiatric disease and more widespread, milder forms of psychological distress will be gained by studying stable personality traits alongside psychiatric symptoms. Such symptoms, while state-dependent, surface against a background of predisposing personality traits, primarily high neuroticism, and, to a lesser extent, low extraversion. In this study, we measure the effect of single nucleotide polymorphisms (SNPs) and genes, with an emphasis on shared effects on personality trait and mood state measures.
