A Twin Registry Study of Familial and Individual Risk Factors for Trauma Exposure and Posttraumatic Stress Disorder

Abstract

This study examines the association of individual and familial risk factors with exposure to trauma and posttraumatic stress disorder (PTSD) in male twins (N = 6744) from the Vietnam Era Twin Registry. Independent reports of familial psychopathology from co-twins were used to avoid the potential biases of the family history method. Risk for exposure to traumatic events was increased by service in Southeast Asia, preexisting conduct disorder, preexisting substance dependence, and a family history of mood disorders whose effects appear to be partly genetic. Preexisting mood disorders in the individual were associated with decreased odds of traumatic exposure. Risk of developing PTSD following exposure was increased by an earlier age at first trauma, exposure to multiple traumas, paternal depression, less than high school education at entry into the military, service in Southeast Asia, and preexisting conduct disorder, panic disorder or generalized anxiety disorder, and major depression. Results suggest the association of familial psychopathology and PTSD may be mediated by increased risk of traumatic exposure and by preexisting psychopathology.

Conduct disorder, war zone stress, and war‐related posttraumatic stress disorder symptoms in American Indian Vietnam veterans

“…Posttraumatic stress disorder (PTSD) is a common and serious problem among U.S. military combat veterans (Koenen et al, 2002). Studies consistently find that the severity of war-related PTSD symptoms is positively associated with the degree of exposure to war zone stress.…”

“…Childhood antisocial behavior is another important factor associated with exposure to war zone combat and PTSD symptoms in national samples of Vietnam veterans Koenen et al, 2002). People with antisocial characteristics may perceive less threat in a war (King et al, 1996), and risk-taking behavior associated with childhood conduct disorder (CD) may increase chances of trauma exposure (Koenen et al, 2002).…”

“…People with antisocial characteristics may perceive less threat in a war (King et al, 1996), and risk-taking behavior associated with childhood conduct disorder (CD) may increase chances of trauma exposure (Koenen et al, 2002). Individuals with CD may have insufficient resources to cope with the sequelae of stressful or traumatic events once exposed (Koenen et al, 2002).…”

“…CD was associated with elevated war-related PTSD symptoms among male AI Vietnam Veterans independent of war zone stress level and other mediators. Future efforts should examine reasons for this association and whether the association exists in other AI populations.Posttraumatic stress disorder (PTSD) is a common and serious problem among U.S. military combat veterans (Koenen et al, 2002). Studies consistently find that the severity of war-related PTSD symptoms is positively associated with the degree of exposure to war zone stress.…”

“…These factors can include demographic variables such as age and education, service factors such as rank, and the presence of other mental illness, including substance dependence (Brewin, Andrews, & Valentine, 2000;Davidson, Hughes, Blazer, & George, 1991;Frueh, Brady, & de Arellano, 1998;Green et al, 1990;King, King, Foy, & Gudanowski, 1996;Wolfe, Erickson, Sharkansky, King, & King, 1999). For instance, males who are younger when they enter the military experience higher levels of combat than those who are older at entry (King et al, 1996).Childhood antisocial behavior is another important factor associated with exposure to war zone combat and PTSD symptoms in national samples of Vietnam veterans Koenen et al, 2002). People with antisocial characteristics may perceive less threat in a war (King et al, 1996), and risk-taking behavior associated with childhood conduct disorder (CD) may increase chances of trauma exposure (Koenen et al, 2002).…”