Table 1.

Descriptive Information for Marijuana Use, Alcohol Use, and Sexual Risk Behaviors

Variable	Baseline	3-Month follow-up	6-Month follow-up	12-Month follow-up	18-Month follow-up
Marijuana use:
Underreported (tested positive but reported no use)	1.0%	8.1%	8.9%	5.8%	6.7%
Consistent (tested and reported same)	52.2%	66.9%	65.3%	70.0%	70.9%
Self-reported only (tested negative but reported use)	42.4%	14.1%	13.6%	14.0%	10.9%
Missing urine test	4.4%	10.9%	12.3%	10.1%	11.5%
Total	100.0%	100.0%	100.2%	99.9%	100.0%
n	297	248	236	207	165
Alcohol use:
Never	38.4%	71.0%	74.6%	69.1%	61.8%
1 to 4 times	30.3%	23.0%	18.2%	19.3%	21.2%
5 or more times	31.3%	6.0%	7.2%	11.6%	17.0%
Total	100.0%	100.0%	100.0%	100.0%	100.0%
n	297	248	236	207	165
Sexual risk behavior:
None	55.7%	53.7%	51.1%	47.6%	41.8%
1 sexual risk behavior	25.0%	30.1%	29.8%	29.6%	33.9%
Both sexual risk behaviors	19.3%	16.3%	19.1%	22.8%	24.2%
Total	100.0%	100.1%	100.0%	100.0%	99.9%
n	296	246	235	206	165

Note. The sexual risk behaviors refer to responses to the following items: (1) Had sexual intercourse without using a condom, and/or (2) Had sex with two or more people. Total percentages across waves may be less than or greater than 100% due to rounding errors.