Table 1.

Sample demographics and marijuana use characteristics (n = 89)

Variable	M	SD
Age	21.4	4.5
Years of education	13.8	1.7
Percent marijuana use days	72.5	21.9
Times used marijuana on average day	2.0	1.2
Percent alcohol use days	29.5	19.6
Alcohol drinks per drinking day	4.2	2.4
Percent heavy drinking days	13.2	13.5
Percent smoking tobacco days (for n = 42 tobacco smokers)	58.0	41.3
Tobacco cigarettes per smoking day	4.1	3.8
	n	%
Gender
Male	59	66
Female	30	34
Marital Status
Single/Never Married	79	89
Other	10	11
Age of initiation of marijuana use
14 or younger	33	37
15–16	30	34
17 or older	26	29
Age of initiation of regular marijuana use
14 or younger	9	10
15–16	24	27
17 or older	56	63
Marijuana ounces used per week
1/16th or less	30	34
1/8th	26	29
1/4th –1/2	26	29
More than ½	7	8
DSM-IV Diagnosis
Lifetime cannabis dependence	18	20
Past year cannabis dependence	12	14
Lifetime cannabis abuse	46	52
Past year cannabis abuse	27	30