Table II.

Descriptive Characteristics of Participants

	ADHD probands M (SD)	siblings of ADHD probands M (SD)
Demographic Variables
N	202	93
Sex	168 M, 34 F	34 M, 59 F
Age	10.7 (2.5)	10.9 (2.6)
Socioeconomic status	2.9 (1.2)	3.0 (1.2)
WISC-R
Full Scale IQ*	103.2 (12.0)	107.8 (13.6)
Verbal IQ*	104.2 (15.4)	108.7 (14.2)
Performance IQ*	101.1 (11.0)	105.1 (12.2)
ADHD symptoms
Inattention*	7.3 (1.8)	1.2 (1.6)
Hyperactivity – impulsivity*	4.0 (2.8)	.9 (1.6)
Total symptoms*	11.2 (3.2)	2.2 (2.6)
Rate of Comorbidity
Oppositional Defiant Disorder	17%	--
Conduct Disorder	12%	--
Social Anxiety Disorder	10%	--
Generalized Anxiety Disorder	17%	--
Major Depressive Disorder	5%	--

^*Indicates means are significantly different at the p < .01 level.

Note. WISC-R = Wechsler Intelligence Scale for Children (Wechsler, 1974).