The intersection of behavioral genetics and political science: introduction to the special issue.

Political Science, Microbiology and Biochemistry, The Pennsylvania State University, USA.
Twin Research and Human Genetics (Impact Factor: 1.64). 02/2012; 15(1):1-5. DOI: 10.1375/twin.15.1.1
Source: PubMed

ABSTRACT The collection of papers in this special edition of Twin Research and Human Genetics represents a major land-mark at the intersection of behavioral genetics and political science. This issue is the fruit of 20 political scientists attending the Behavioral Genetics Association Methods Workshop in Boulder and a hands-on training practicum at the Virginia Institute for Psychiatric and Behavioral Genetics, and includes results from the first wave of political science twin surveys.

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    ABSTRACT: To determine whether posttraumatic stress disorder (PTSD) is associated with coronary heart disease (CHD) using a prospective twin study design and objective measures of CHD. It has long been hypothesized that PTSD increases the risk of CHD but empirical evidence using objective measures is limited. We conducted a prospective study of middle-aged male twins from the Vietnam Era Twin Registry. Among twin pairs without self-reported CHD at baseline, we selected pairs discordant for a lifetime history of PTSD, pairs discordant for a lifetime history of major depression, and pairs without either condition. All underwent a clinic visit after a median follow-up of 13 years. Outcomes included clinical events (myocardial infarction, other hospitalizations for CHD and coronary revascularization) and quantitative measures of myocardial perfusion by [N13] positron emission tomography, including a stress total severity score (STSS) and coronary flow reserve (CFR). A total of 562 twins (281 pairs) were included with mean age of 42.6 yrs at baseline. The incidence of CHD was more than double in twins with PTSD (22.6%) than those without PTSD (8.9%; p<0.001). The association remained robust after adjusting for lifestyle factors, other CHD risk factors and major depression (OR=2.2, 95% confidence interval, 1.2-4.1). STSS was significantly higher (+ 95%, p=0.001) and CFR lower (-0.21, p=0.02) in twins with PTSD than those without, denoting worse myocardial perfusion. Associations were only mildly attenuated within 117 twin pairs discordant for PTSD. Among Vietnam era veterans, PTSD is a risk factor for CHD.
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    ABSTRACT: There is a growing interest in empirically exploring the biological underpinnings of political attitudes and behavior. Heritability studies are a primary vehicle for conducting such investigations and data sets rich in political phenotypes are becoming broadly accessible. A bottleneck exists, however, in exploiting these opportunities because they involve a statistical re-tooling for political scientists and require a conceptual shift that has substantial implications for the field’s traditional theoretical models. Methodologically, most twin studies rely on structural equation models unfamiliar to political scientists. We show this methodological bottleneck is easily navigable; it is the lesser discussed shift in theoretical assumptions poses the larger problem to integrating biological elements into the study of political attitudes and behavior. To address these issues we provide a detailed introduction to a regression-based method for analyzing genetic influence on political attitudes and behaviors that will be methodologically intuitive to political scientists with even minimum quantitative training. In doing so, we provide a platform for bridging important conceptual divides between political science and behavioral genetics.
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    ABSTRACT: To examine the influence of conduct disorder (CD) on substance use initiation. Community adolescents without CD (n = 1,165, mean baseline age = 14.6 years), with CD (n = 194, mean baseline age = 15.3 years), and youth with CD recruited from treatment (n = 268, mean baseline age = 15.7 years) were prospectively followed and re-interviewed during young adulthood (mean ages at follow-up respectively: 20, 20.8, and 24). Young adult retrospective reports of age of substance initiation for 10 substance classes were analyzed using Cox regression analyses. Hazard ratios of initiation for the CD cohorts (community without CD as the reference) at ages 15, 18, and 21 were calculated, adjusting for baseline age, gender, and race/ethnicity. Among community subjects, CD was associated with elevated adjusted hazards for initiation of all substances, with comparatively greater hazard ratios of initiating illicit substances at age 15 years. By age 18, the adjusted hazard ratios remained significant except for alcohol. At age 21, the adjusted hazard ratios were significant only for cocaine, amphetamines, inhalants, and club drugs. A substantial portion of community subjects without CD never initiated illicit substance use. Clinical youth with CD demonstrated similar patterns, with comparatively larger adjusted hazard ratios. CD confers increased risk for substance use initiation across all substance classes at age 15 years, with greater relative risk for illicit substances compared to licit substances. This effect continues until age 18 years, with the weakest effect for alcohol. It further diminishes for other substances by age 21, However, the likelihood of initiating cocaine, amphetamines, inhalants and club drug use among those who have not initiated yet continues to be highly elevated by age 21.
    Journal of the American Academy of Child and Adolescent Psychiatry 05/2013; 52(5):511-518.e4. · 6.97 Impact Factor