Table 1. Overview of methadone dose genome-wide association study (GWAS) sample.

All subjects met criteria for DSM-IV lifetime opioid dependence (OD), had been treated with methadone, and reported their usual daily methadone dose. A maximum of seven DSM-IV OD criteria can be endorsed. Kilograms (kg), milligrams (mg), standard deviation (SD).

	African-Americans	European-Americans
Sample size	383	1,027
Men
Subjects, n (%)	225 (58.8)	617 (60.1)
DSM-IV OD criteria, mean	6.5	6.7
Age, mean (SD), years	45.6 (8.4)	37.2 (10.1)
Weight, mean (SD), kg	87.7 (17.3)	88.0 (17.6)
Methadone dose, mean (SD), mg	66.1 (29.8)	77.7 (33.1)
Women
Subjects, n (%)	158 (41.3)	410 (39.9)
DSM-IV OD criteria, mean	6.4	6.7
Age, mean (SD), years	43.0 (7.2)	37.5 (9.8)
Weight, mean (SD), kg	82.4 (21.9)	71.5 (16.5)
Methadone dose, mean (SD), mg	70.7 (31.8)	78.1 (35.1)