Table 1.

Standardized^a Means (± S.D.) at Initial and Follow-up Assessments^b

	Initial		Follow-up
	Proband	Cotwin	Proband	Cotwin
Reading
MZ	−2.30 ± .84	−2.12 ± 1.01	−2.04 ± .76	−1.87 ± .97
DZ	−2.25 ± .88	−1.36 ± 1.26	−1.91 ± .79	−1.07 ± 1.20
Inattention
MZ	1.59 ± 1.51	1.40± 1.60	1.47 ± 1.61	1.19 ± 1.68
DZ	1.50 ± 1.58	0.74 ± 1.51	1.28 ± 1.98	0.43 ± 1.41
Hyp-Imp
MZ	1.02 ± 1.64	0.91 ± 1.64	0.62 ± 1.34	0.53 ± 1.36
DZ	.98 ± 1.59	0.69 ± 1.46	0.86 ± 2.04	0.61 ± 1.66

^aagainst Contemporaneous Control Means

^bthe sample sizes for the measures include 767 pairs in which both members have DISCR scores at initial assessment, 345 pairs in which both members have DISCR and ADHD scores at initial assessment, 94 pairs in which probands have DISCR scores at initial assessment and cotwins have DISCR scores at follow-up, and 88 pairs in which both members have DISCR scores at initial assessment and ADHD scores at follow-up.