title: A twin study of generalized anxiety disorder symptoms, panic disorder symptoms and post-traumatic stress disorder in men.
abstract: Generalized anxiety disorder (GAD), panic disorder (PD) and post-traumatic stress disorder (PTSD) often co-occur. We investigated whether and to what degree genetic and environmental contributions overlap among symptoms of GAD, symptoms of PD and PTSD. Subjects were 3327 monozygotic and dizygotic male-male twin pair members of the Vietnam Era Twin Registry who participated in a 1992 telephone administration of the Diagnostic Interview Schedule Version 3 Revised (DIS3R). Genetic model fitting was performed to estimate the magnitude of genetic and environmental contributions to the lifetime co-occurrence of GAD symptoms, PD symptoms and PTSD. The liability for GAD symptoms was due to a 37.9% additive genetic contribution common to PD symptoms and PTSD. Liability for PD symptoms was due to a 20.7% additive genetic contribution common to GAD symptoms and PTSD, and a 20.1% additive genetic influence specific to PD symptoms. Additive genetic influences common to symptoms of GAD and PD accounted for 21.3% of the genetic variance in PTSD. Additive genetic influences specific to PTSD accounted for 13.6% of the genetic variance in PTSD. Remaining variance for all three disorders was due to unique environmental factors both common and specific to each phenotype. These results suggest that these disorders each have etiologically distinct components and also have significant genetic and unique environmental contributions in common.
authors.affiliation: Research Service 151-JC, St. Louis VAMC, 915 North Grand Blvd., St. Louis, MO 63106, USA.
authors.forename: S I
authors.initials: SI
authors.lastname: Chantarujikapong
authors.forename: J F
authors.initials: JF
authors.lastname: Scherrer
authors.forename: H
authors.initials: H
authors.lastname: Xian
authors.forename: S A
authors.initials: SA
authors.lastname: Eisen
authors.forename: M J
authors.initials: MJ
authors.lastname: Lyons
authors.forename: J
authors.initials: J
authors.lastname: Goldberg
authors.forename: M
authors.initials: M
authors.lastname: Tsuang
authors.forename: W R
authors.initials: WR
authors.lastname: True
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D003130:Combat Disorders / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D004200:Diseases in Twins / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D016584:Panic Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D010641:Phenotype; D012042:Registries; D012931:Social Environment; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D014728:Veterans / Q000523:psychology*; D014744:Vietnam