[A twin study of personality disorder heritability].
OBJECTIVE
To calculate heritabilities of personality disorders (PDs) in twin population.


METHODS
Based on informed consent, we used Personality Diagnostic Questionnaire (fourth-version) as our screening tool to study the adult twins (aged 20 - 70 years) in Qingdao city. There were 324 twin pairs whose zygosity had been determined. Structural equation modeling was used to estimate the heritabilities by 242 same-sex twin pairs.


RESULTS
The best-fitting models yielded a heritability of 68.26% (60.26 - 74.78) of overall PDs, 59.00% (49.22 - 67.17) of cluster A, 64.99% (56.24 - 72.16) of cluster B, and 63.66% (54.72 - 71.02) of cluster C. There were significant genetic effects for schizotypal, narcissistic and dependent, explaining 49.96% (37.94 - 60.14), 52.89% (41.85 - 62.24) and 68.87% (60.80 - 75.40) of the variance respectively. No genetic effects were found on Histrionic, but common environmental effect accounted for 54.08% (44.50 - 62.43) of the total variances.


CONCLUSIONS
PD was mainly determined by genetic factor. These findings may provide evidence for future research on PD.
Ji
Wen-yan
WY
Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing 100083, China.
Hu
Yong-hua
YH
Huang
Yue-qin
YQ
Cao
Wei-hua
WH
Lv
Jun
J
Qin
Ying
Y
Pang
Zeng-chang
ZC
Wang
Shao-jie
SJ
Li
Li-ming
LM
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002681:China; D016000:Cluster Analysis; D004200:Diseases in Twins / Q000235:genetics*; D004777:Environment; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D008957:Models, Genetic; D010554:Personality Disorders / Q000235:genetics*; D010555:Personality Inventory; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult