Table 1.

Participant characteristics compared across treatment modality

Variable	Full sample (N=800)	Outpatient psychosociala (n=414)	Methadone maintenanceb (n=386)	Prevalence Ratio
Number of stimulant-negative urine resultsc	9.15 (0.30)	11.11 (0.42)	7.05 (0.40)	t(797.69) = 6.95 p < .001
Demographic characteristics
Age 40 years or more	45	31	60	0.52 (0.44, 0.61)
Female	50	55	44	1.26 (1.09, 1.45)
Caucasian	31	36	26	1.36 (1.10, 1.68)
Social characteristics
Married/cohabiting	19	24	14	1.72 (1.27, 2.34)
Lives with a drug user	23	21	25	0.83 (0.64, 1.07)
Currently employed	34	35	32	1.09 (0.89, 1.32)
Usually employed	58	65	50	1.32 (1.17, 1.49)
Legal problem severity
Recent incarceration	8	12	4	2.69 (1.58, 4.58)
Current probation or parole	26	35	16	2.23 (1.71, 2.91)
Psychiatric severity
High psychiatric distress	19	18	19	0.98 (0.74, 1.32)
Prior psychiatric treatment	51	49	53	0.92 (0.81, 1.06)
Drug use severity
Recent inpatient drug treatment	13	24	1	23.31 (8.66, 62.71)
Drug positive at study intake
Cocaine	43	17	71	0.24 (0.19, 0.30)
Methamphetamine	8	9	7	1.38 (0.85, 2.25)
Cannabis	12	11	12	0.87 (0.60, 1.28)
Alcohol	1	1	1	0.70 (0.16, 3.11)
Opiate	24	3	47	0.07 (0.04, 0.12)
Substance use disorder
Cocaine	69	60	79	0.76 (0.69, 0.84)
Methamphetamine	18	27	8	3.63 (2.48, 5.33)
Cannabis	15	21	8	2.50 (1.70, 3.68)
Alcohol	30	42	17	2.51 (1.96, 3.22)

Note. Results are presented as percent of column sample, and comparisons are given as prevalence ratios with 95% confidence intervals, except where noted. The reference category is methadone maintenance treatment modality.

^aOutpatient psychosocial sample is missing 0–1 participants per variable.

^bMethadone maintenance sample is missing 0–14 participants per variable.

^cMean (SEM); t-test comparison.