Differential etiology of posttraumatic stress disorder with conduct disorder and major depression in male veterans.
BACKGROUND
Epidemiologic studies reveal that posttraumatic stress disorder (PTSD) is highly comorbid with both conduct disorder and major depression in men. The genetic and environmental etiology of this comorbidity has not been examined.


METHODS
Data were analyzed from 6744 middle-aged male-male monozygotic and dizygotic twins from the Vietnam Era Twin Registry. Conduct disorder, major depression, and PTSD were assessed via telephone interview using the Diagnostic Interview Schedule for the DSM-III-R in 1992. Structural equation modeling was used to estimate additive genetic, shared environmental, and individual-specific environmental effects common and specific to conduct disorder, major depression, and PTSD.


RESULTS
The association between conduct disorder and PTSD was explained primarily by common shared environmental influences; these explained 10% (95% confidence interval: 6%-17%) of the variance in PTSD. The association between major depression and PTSD was largely explained by common genetic influences; these explained 19% (95% confidence interval: 11%-26%) of the variance in PTSD.


CONCLUSIONS
Our findings suggest that different etiologic mechanisms explain the association of conduct disorder and major depression with PTSD in male veterans. If replicated in other populations, results suggest research aimed at identifying specific genetic and environmental factors that influence PTSD may benefit from starting with those that have been more consistently and strongly associated with major depression and conduct disorder.
Fu
Qiang
Q
Department of Community Health, Saint Louis University School of Public Health, St. Louis, Missouri 63104, USA. qjfu@slu.edu
Koenen
Karestan C
KC
Miller
Mark W
MW
Heath
Andrew C
AC
Bucholz
Kathleen K
KK
Lyons
Michael J
MJ
Eisen
Seth A
SA
True
William R
WR
Goldberg
Jack
J
Tsuang
Ming T
MT
D000368:Aged; D019955:Conduct Disorder / Q000150:complications / Q000453:epidemiology*; D016001:Confidence Intervals; D003865:Major Depressive Disorder / Q000150:complications / Q000453:epidemiology*; D004200:Diseases in Twins / Q000453:epidemiology* / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015995:Prevalence; D013313:Stress Disorders, Post-Traumatic / Q000150:complications / Q000453:epidemiology* / Q000209:etiology; D018433:Twin Studies as Topic; D014728:Veterans / Q000706:statistics & numerical data