Behavior Genetic Study of Self-Harm, Suicidality, and Personality in African American and White Women Doctoral thesis

摘要

This study is an examination of the genetic and environmental risk factors leading to suicidal and self-harm behaviors in a representative community sample of female adolescents and young adults, and racial differences in the relative strength of those risk factors. Using a behavior genetic twin study design, suicidal and self-harm behaviors proved to be moderately heritable, and were influenced by non-shared environment but not by shared environment. The two phenotypes shared a moderate genetic correlation and a weak environmental correlation. After accounting for genetic influence common to both, self-harm but not suicide attempts had significant unique genetic variance remaining. When examined by race, suicidal behaviors were more common in African American women than White women, while self-harm was equally prevalent. However, the heritability of self-harm and suicide attempts did not vary by race. Further analyses were conducted to determine the extent to which genetic variation in self-harm and suicide attempts could be accounted for by personality traits (Neuroticism and Novelty Seeking) and psychiatric diagnoses. Personality traits and diagnostic status did not differentially predict self-harm or suicidal behavior by race in multivariate regressions. Neuroticism shared significant genetic variance with both self-harm and suicide attempts, and Novelty Seeking shared significant genetic variance with self-harm.