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. Author manuscript; available in PMC: 2019 Aug 1.
Published in final edited form as: J Abnorm Child Psychol. 2018 Aug;46(6):1217–1228. doi: 10.1007/s10802-017-0361-y

Table 3.

Twin Intraclass and Cross Correlations

Age 2 CU ADHD ODD



MZ DZ MZ DZ MZ DZ
CU .72 (.63–.78) .41 (.28–.52)
ADHD .49 (.42–.56) .29 (.18–39) .74 (.66–.79) .39 (.25–.50)
ODD .52 (.44–.59) .30 (.19–39) .55 (.48–.62) .32 (.21–41) .72 (.64–.78) .41 (.28–.52)

Age 3 CU ADHD ODD



MZ DZ MZ DZ MZ DZ

CU .63 (.52–.71) .41 (.28–.52)
ADHD .49 (.41–56) .27 (.16–37) .78 (.72–.83) .28 (.13–.41)
ODD .44 (.35–.52) .36 (.25–.45) .47 (.39–.54) .28 (.17–39) .66 (.56–.73) .41 (.27–.53)

Note. Intraclass correlations are in bold. Cross-twin, cross-trait correlations are below the diagonal. All correlations are significant at p < .05.