Table 1. Demographic and Clinical Characteristics of Subjects.

	Control subjects (n=10; an=22)	MA users (n=28)	Cocaine users (n=9)	p-Value
				MA vs controls	MA vs cocaine
Age	28.6±5.8a	26.6±5.7	31.2±7.7	0.22	0.06
Gender (M)	12	12	3	0.41	0.61
Education (years)	16.8±2.6a	13.1±2.7	13.3±2.7	<0.000	0.83
IQb	111.6±12.9	101.4±12.2	100.7±8.8	0.03	0.38
BDI	1.1±1.5a	14.6±10.9	9.3±12.7	<0.000	0.23
Ethnicity	16(W), 6(A)a	17 (W), 1 (A), 2 (B), 8 (M)	7 (W), 1 (A), 1 (M)	0.01	0.47
Cigarette smokers	4a	24	7	<0.000	0.57
Cigarettes per daya	0.5±1.3	9.5±5.6	9.7±5.3	<0.000	0.80
Alcohol (drinks per week)	0.6±1.0	4.1±7.3	3.2±5.7	0.14	0.74
Cannabis users (⩾1 × /months)	3a	18	7	0.02	0.45
Cannabis use (days per week)	1.0±1.4	3.3±3.1	3.5±3.3	0.315	0.91
Dose injected (mCi)
S1	9.85±0.6a	9.70±0.9	9.78±0.7	0.47	0.80
S2	9.83±0.5	9.69±0.8	9.62±0.6	0.62	0.82
Spec. act. (mCi/μmol)
S1	2058.50±651.1a	2686.99±1071.7	2478.66±1189.3	0.02	0.62
S2	2220.89±910.8	2606.32±1104.9	2181.45±1105.0	0.38	0.38
Interscan interval (days)	6.3±1.7 (n=9)	6.9±1.1 (n=17)	6.6±1.2 (n=8)	0.96	0.52

Abbreviations: A, Asian; B, Black; BDI, Beck Depression Inventory; IQ, intelligence quotient; M, mixed; MA, methamphetamine; S1, scan 1; S2, scan 2; spec. act., [¹¹C]DTBZ specific activity at the time of the injection; W, White.

^aData compiled using the subset of control subjects (n=10) who participated in this longitudinal study plus control data taken from our previous study (Boileau et al, 2008).

^bIQ as measured by Shipley-2 composite A scale.

Bold values indicate significance at p<0.05.