Table 1.

Participant demographic and clinical characteristics (means and standard deviations are shown)

N = 85	Substance abusers n = 29	Substance abusers with marijuana dependence n = 30	Healthy controls N = 26	p*
Gender no. male	17 (58.6%)	18 (60.0%)	10 (40%)	NS
Race				>0.02
No. Caucasian	18 (62.1%)	9 (30%)	14 (56%)
No. African American	8 (27.6%)	20 (66.7%)	7 (28%)
Other	3 (10.3%)	1 (3.3%)	4 (16%)
Age	37.1 ± 6.4	33.7 ± 6.9	28.1 ± 1.4	<0.0001
Years in education	12.4 ±0.3	12.3 ± 0.4	15.1 ± 0.4	<0.0001
Smoking status no. regular smokers (%)	25 (86.2%)	26 (86.7%)	6 (24%)	<0.0001
Years of cocaine use	8.5 ± 5.4	8.2 ± 5.3	0	<0.0001
Years of alcohol use	15.7 ±8.9	11.9 ±7.3	4.8 ± 1.2	<0.0001
Years of marijuana use	5.3 ±13.2	13.2 ± 5.5	1.0 ± 0.6	<0.0001
No. of days used in the last month
Cocaine	12.4 ±12.3	10.1 ±11.5	0	<0.0001
Alcohol	14.5 ±12.4	9.4 ± 11.7	3.8 ± 3.6	<0.0001
Marijuana	0.6 ± 2.2	9.1 ± 12.7	0	<0.0001
Amount used in the last month
Cocaine (grams)	25.2 ± 23.7	36.3 ± 52.5	0	<0.0001
Alcohol (drinks)	203.7 ±138.4	159.8 ± 119.4	16.4 ±13.5	<0.0001
Marijuana (joints)	5.3 ± 10.5	96.6 ± 185.7	0	<0.0001
No. lifetime depression	8 (27.6%)	8 (26.7%)	1 (4%)	<0.0001
No. lifetime anxiety (including PTSD**)	10 (34.5%)	12 (40%)	1 (4%)	<0.0001
No. lifetime anxiety (without PTSD**)	2 (6.9%)	2 (6.7%)	0	<0.0001

^*Overall statistical difference between all three groups. Shaded area represents significant differences (p < 0.05) between the two substance-abusing groups only.

^**PTSD: Post Traumatic Stress Disorder.