Structure of genetic and environmental risk factors for dimensional representations of DSM-IV anxiety disorders.
BACKGROUND
Twin data permit decomposition of comorbidity into genetically and environmentally derived correlations. No previous twin study includes all major forms of anxiety disorder.


OBJECTIVE
To estimate the degree to which genetic and environmental risk factors are shared rather than unique to dimensionally scored panic disorder, generalised anxiety disorder, phobias, obsessive-compulsive disorder and post-traumatic stress disorder.


METHODS
Data obtained from 2801 young-adult Norwegian twins by means of the Composite International Diagnostic Interview were analysed with the Mx program.


RESULTS
A multivariate common factor model fitted best. The latent liability to all anxiety disorders was substantially more heritable (54%) than the individual disorders (23% to 40%). Most of the genetic effect was common to the disorders. Genes contributed just over 50% to the covariance between liabilities.


CONCLUSIONS
The five anxiety disorders all share genetic and environmental risk factors. This has implications for the revision of the anxiety disorder section in DSM-V.
Department of Mental Health, Norwegian Institute of Public Health, Box 4404 Nydalen, 0403 Oslo 3, Norway. kristian.tambs@fhi.no
Kristian
K
Tambs
Nikolai
N
Czajkowsky
Espen
E
Røysamb
Michael C
MC
Neale
Ted
T
Reichborn-Kjennerud
Steven H
SH
Aggen
Jennifer R
JR
Harris
Ragnhild E
RE
Ørstavik
Kenneth S
KS
Kendler
D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D015897:Comorbidity; D003627:Data Interpretation, Statistical; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004200:Diseases in Twins / Q000453:epidemiology* / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D009664:Norway; D010641:Phenotype; D012307:Risk Factors; D012931:Social Environment; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D018433:Twin Studies as Topic; D014429:Twins, Dizygotic / Q000235:genetics / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics / Q000523:psychology; D055815:Young Adult