Table 1.

Sample characteristics.

	Total	Emerging adults (18–25)	Older adults (26+)	p
	N = 294	n = 70	n = 224
Demographics
Age, mean (SD)	35.6 (8.1)	23.1 (1.7)	39.5 (9.2)	< .01	*
Gender, female %	41.5	35.7	43.3	0.26
Race, Caucasian %	92.2	97.1	90.6	0.08	†
No. of days worked in past 30 days, mean (SD)	3.9 (7.4)	4.3 (7.2)	3.7 (7.5)	0.41
Currently receiving disability income, %	22.5	2.9	28.6	< 0.01	*
Past-year history of psychiatric medication, %	67.4	53.6	71.6	< 0.01	*
Recent substance use patterns
Self-reported use in past 30 days
Alcohol	13.6	12.9	13.8	0.83
Cannabis	12.2	21.4	9.4	< 0.01	*
Cocaine	10.5	8.6	11.2	0.54
No other substance use	39.8	34.3	41.5	0.28
Urine toxicology screening at intake
Alcohol	5.8	5.8	5.7	0.97
Cannabis	27.9	41.4	23.7	< 0.01	*
Cocaine	17.0	15.7	17.4	0.74
Amphetamine	6.1	4.3	6.7	0.46
Benzodiazepine	29.3	25.7	30.4	0.46
Opioid dependence severity
No. of previous detoxification visits, mean (SD)	1.9 (2.0)	2.5 (1.9)	3.0 (2.0)	0.12
Lifetime heroin use, %	77.9	81.4	76.8	0.41
Heroin use in the past 30 days, %	18.0	22.9	16.5	0.23
History of injection drug use, %	56.8	64.3	54.5	0.15
Opioid dependence experience
Started during adolescence (< 18 years), %	31.0	57.1	22.8	< 0.01	*
Total years of opioid use, mean (SD)	13.5 (8.4)	6.0 (2.3)	15.8 (9.6)	< 0.01	*
Short duration of opioid use (< 2 years), %	2.4	7.1	0.9	< 0.01	*

^*p < 0.05.

^†p < 0.10.