Heritability of fear: Ukrainian experience
Background: A wide range of normal and clinically significant behavior traits, including fears, were intensively studied and heritability coefficients were obtained for many of them. A heritability value is a population-based trait, so it may significantly vary in different human populations. In the former Soviet Union, research on human behavior traits was mostly tabooed. Ukraine is a population with a unique history and cultural background and with a specific multiethnic composition. Until 1991, Ukraine was part of the former Soviet Union. The current research is devoted to heritability of fear assessment in Ukrainian megapolice sample.
Subjects and methods: 2305 individuals (741 males and 1564 females), aged 14–72 years, participated in the current study. Data were collected during 2004–2007. All participants lived in Ukraine and were Slavs (predominantly Ukrainians and Russians). Most of them were Kharkov city residents (Kharkov is the second city in Ukraine by its population size after the capital Kiev city, and Kharkov region includes about 1,730,000 inhabitants). Most participants were engaged without relatives and were used only for population distribution evaluation. Some volunteers were enrolled with a relative of the first degree of relatedness (with a parent or a sibling). These formed 352 parent– offspring pairs and 104 sibling pairs. Spouses were enrolled in the experiment for a potential assortative mating effect searching. The total number of marital couples was 74. 24 emotional states of fear have been studied by Ivleva–Shcherbatyh questionnaire, which was developed and validated by Russian psychologists in Slavs samples. Evaluation and decomposition of total phenotypic variance were performed according to the classical Falconer approach, based on correlation coefficients between relatives. Assortative mating effect was taken into account and correlation coefficients between relatives were adjusted for traits with statistically significant correlation coefficients between wives and husbands.
Results: As a result of the research, correlation coefficients of fears q between relatives and mates were obtained in the range 0.18–0.77. In majority of cases, correlation coefficients were higher in sibling pairs compared to «parent–offspring» pairs. For three fears (psychiatric disorders development, disease of relatives, and suicide commitment) there was a positive assortative mating in the population (correlation coefficients q were in the range 0.35–0.43), so for these traits, correlation coefficients’ modification between relatives was needed to be done. Heritability coefficients of nine types of fear were in the range 26–48%, among them the lowest heritability coefficient was recorded for fear of suicide commitment and the highest one was recorded for fear of aggressive behavior possibility to the relatives.
Conclusions: The conducted research demonstrated genetic component presence for nine types of fear – psychic disorder development, complications in personal life, making responsible decisions, senility, closed spaces, sexual dysfunction, suicide commission, speaking in public, and aggressive behavior possibility to relatives. It helps to consider these fear perspectives for further molecular-genetic analysis in Ukraine.
Keywords: Fear; Ukraine; Heritability; Parent–child; Sibling; Assortative mating