. Author manuscript; available in PMC: 2012 Nov 1.

Published in final edited form as: J Child Psychol Psychiatry. 2011 May 31;52(11):1155–1163. doi: 10.1111/j.1469-7610.2011.02420.x

Table 3.

Twin Intraclass Correlations, Cross-twin Cross-trait Correlations: IC and Related Behavior Problems.


Observed IC		Parent IC		Externalizing problems		ADHD-DSM problems
MZ	DZ	MZ	DZ	MZ	DZ	MZ	DZ
.41^**	.15^**	.85^**	.55^**	.81^**	.59^**	.72^**	.35^**

Cross-twin Cross-trait Correlations
	Observed IC		Parent IC
	MZ	DZ	MZ	DZ
Externalizing problems	−.16^**	−.06	−.51^**	−.27^**
ADHD-DSM problems	−.20^**	−.11^*	−.47^**	−.27^**

Note.

p < .05,

^**

p < .01.

MZ=monozygotic twins, DZ=dizygotic twins.