Table 2.

Means and Standard Deviations for study variables (N = 95).

Variable	Mean	SD	% of sample
Age Year 1	18.92	.45
Female			53.2%
PEP Response to Reward	−.09	2.97
PEP Response to Extinction	−.34	2.89
EDR Response to Extinction	.34	.47
Frequency of Alcohol Use Year 1	.82	.98
Frequency of Alcohol Use Year 3	.97	.94
Alcohol abstinence rate year 1			20.2
Alcohol abstinence rate year 3			11.6
Frequency of Marijuana Use Year 1	.42	.82
Frequency of Marijuana Use Year 3	.54	1.21
Marijuana abstinence rate year 1			60.0
Marijuana abstinence rate year 3			60.0
Frequency of Cigarette Use Year 1	.57	1.40
Frequency of Cigarette Use Year 3	.61	1.53
Cigarette abstinence rate year 1			82.1
Cigarette abstinence rate year 3			83.2

Note. PEP = Cardiac pre-ejection period response (change from baseline scores), reverse-coded such that higher numbers indicate greater sympathetic activity. EDR = Electrodermal response (change from baseline scores). SD = standard deviation. Substance Use variables represent average frequency of use. “Frequency” ranges from 0–5 and indicates the frequency with which participants used during each month of the past year (0 = did not use, 1 = once a month or less, 2 = once a week, 3 = 2 or 3 times a week, 4 = 4 or 5 times a week, 5 = every day).