Table 1.

Group Characteristics.

	PSU (n=18)		DSU (n=15)		CTL (n=15)

IQ and Anxiety	M	SD	M	SD	M	SD	df	F	p	Description
WTAR Verbal IQ	108.06	5.95	110.33	5.70	116.92	7.82	2, 41	6.91	0.003	CTL > PSU/DSU¹
STAI Trait	35.67	8.69	29.20	4.68	33.27	6.86	2, 45	3.45	0.04	PSU > DSU²

Depression	M	SD	M	SD	M	SD	Kruskal-Wallis p			Description

BDI-II	5.28	6.27	0.47	0.52	1.73	1.87		.002		PSU > DSU/CTL

Initial Visit Drug Use	M	SD	M	SD	M	SD	M-W-U p PSU vs DSU			Description

Amphetamine	36.11	49.49	6.53	6.69	N/A	N/A		.01		PSU > DSU
Cocaine	37.22	85.64	32.40	53.18	N/A	N/A		.61		ns
Marijuana	837.61	1349.05	1085.27	1626.89	N/A	N/A		.63		ns
% Use Due to Stimulants	32.69	36.28	15.66	18.72	N/A	N/A		.16		ns

Interim Drug Use	M	SD	M	SD	M	SD	M-W-U p PSU vs DSU			Description

Amphetamine	170.00	290.16	1.87	3.20	0	0		.001		PSU > DSU/CTL
Cocaine	546.22	1204.76	5.80	16.29	0	0		.01		PSU > DSU/CTL
Marijuana	621.89	1424.27	466.53	575.36	25.53	43.87		.23		PSU/DSU > CTL
% Use Due to Stimulants	72.20	33.15	6.98	14.08	0	0		.001		PSU > DSU/CTL

Note:

Bonferroni post-hoc corrected p<.05.

Games-Howell post-hoc corrected p<.05.

PSU = problem stimulant users. DSU = desisted stimulant users. CTL = healthy comparison subjects. WTAR = Wechsler Test of Adult Reading. IQ = intelligence quotient. BDI-II = Beck Depression Inventory II. STAI = State Trait Anxiety Inventory. Due to BDI-II non-normal distributions the Kruskal-Wallis test was used to determine whether group distributions differed from one another. Drug use was quantified as the number of distinct sessions each substance was used for a particular period; given non-normal distributions for these measures, Mann-Whitney U (M-W-U) tests were employed to test differences in drug use between groups. ns = non-significant. Data were not available for WTAR (n=1 PSU; n=3 CTL).