Table 1.

Sample- and genotype-specific demographics

Genotype		N	Sex		Race		Mean age±s.d.
			Male	Female	White	Non-white
DAT1	Total	86	38	48	78	8	44.2±6.8
	9-repeat carriers	42	18	24	39	3	44.0±6.9
	10/10	44	20	24	39	5	44.4±6.8
DRD4	Total	86	37	49	77	9	44.1±6.8
	7-repeat carriers	34	13	21	30	4	45.1±6.7
	Other	52	24	28	47	5	43.4±6.8
DRD2	Total	76	35	41	70	6	43.8±6.9
	Ins/Ins	58	23	35	55	3	43.7±6.9
	Ins/Del	18	12	6	15	3	43.9±7.1
COMT	Total	86	37	49	77	9	44.1±6.8
	Val/Val	26	9	17	21	5	46.5±6.5
	Val/Met	44	21	23	41	3	43.8±6.5
	Met/Met	16	7	9	15	1	41.0±7.1
ALL	—	89	38	51	79	10	43.8±6.5

There were no significant differences in sex, race or age between any of the genotype groups.

Non-white participants were either African-American or of mixed race.

The age range for the entire sample of 89 subjects was 31–54, and approximately half (44) of the subjects within this sample were aged 45 years and younger (i.e., range 31–45).