Longitudinal stability of the CBCL-juvenile bipolar disorder phenotype: A study in Dutch twins.
BACKGROUND
The Child Behavior Checklist-juvenile bipolar disorder phenotype (CBCL-JBD) is a quantitative phenotype that is based on parental ratings of the behavior of the child. The phenotype is predictive of DSM-IV characterizations of BD and has been shown to be sensitive and specific. Its genetic architecture differs from that for inattentive, aggressive, or anxious-depressed syndromes. The purpose of this study is to assess the developmental stability of the CBCL-JBD phenotype across ages 7, 10, and 12 years in a large population-based twin sample and to examine its genetic architecture.


METHODS
Longitudinal data on Dutch mono- and dizygotic twin pairs (N = 8013 pairs) are analyzed to decompose the stability of the CBCL-JBD phenotype into genetic and environmental contributions.


RESULTS
Heritability of the CBCL-JBD increases with age (from 63% to 75%), whereas the effects of shared environment decrease (from 20% to 8%). The stability of the CBCL-JBD phenotype is high, with correlations between .66 and .77 across ages 7, 10, and 12 years. Genetic factors account for the majority of the stability of this phenotype. There were no sex differences in genetic architecture.


CONCLUSIONS
Roughly 80% of the stability in childhood CBCL-JBD is a result of additive genetic effects.
Boomsma
Dorret I
DI
Department of Biological Psychology, Vrije Universiteit, Amsterdam, The Netherlands. dorret@psy.vu.nl
Rebollo
Irene
I
Derks
Eske M
EM
van Beijsterveldt
Toos C E M
TC
Althoff
Robert R
RR
Rettew
David C
DC
Hudziak
James J
JJ
D000367:Age Factors; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D004200:Diseases in Twins; D004777:Environment; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D010555:Personality Inventory; D010641:Phenotype; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D018433:Twin Studies as Topic; D014427:Twins