Table 3.

Effect of daily co-use of alcohol and marijuana relative to single substance use on daily subjective intoxication

	Daily Subjective Intoxication
	Co-use versus Alcohol Only (n=330)					Co-use versus Marijuana Only (n=317)
	95% CI					95% CI
Predictors	β	Low	High	SE	p	β	Low	High	SE	p
Intercept	2.351	1.690	3.014	.342	-	2.635	1.789	3.488	.437	-
Level 2 (Person)
Male	0.004	−0.083	0.092	.045	.927	0.100	−0.013	0.214	.059	.089
Non-white	−0.034	−0.141	0.074	.056	.543	−0.039	−0.178	0.101	.072	.593
Hispanic/Latino	0.051	−0.099	0.200	.077	.510	0.206	0.012	0.400	.100	.041
Age	−0.054	−0.087	−0.022	.017	.001	−0.058	−0.100	−0.016	.022	.009
School (A)	−0.015	−0.121	0.091	.055	.787	0.039	−0.102	0.180	.073	.596
School (B)	0.084	−0.021	0.189	.054	.123	0.097	−0.043	0.237	.073	.183
AUDIT	−0.007	−0.015	0.002	.005	.146	0.005	−0.006	0.016	.006	.381
CUDIT-R	0.014	0.006	0.021	.004	<.001	0.010	−0.001	0.020	.005	.070
Level 1 (Day)
Any daily nicotine	0.043	−0.017	0.101	.030	.151	0.082	0.031	0.132	.026	.002
Any daily other drugs	0.123	0.034	0.212	.045	.007	0.130	0.058	0.202	.037	<.001
Non-plant	0.000	−0.068	0.069	.035	.991	0.008	−0.035	0.050	.022	.720
Weekend	0.161	0.120	0.201	.021	<.001	0.111	0.077	0.145	.017	<.001
# drinks	0.157	0.149	0.164	.004	<.001
# marijuana uses						0.032	0.028	0.036	.002	< .001
Daily co-use	0.589	0.521	0.658	.035	<.001	0.262	0.226	0.298	.018	<.001
# drinks * daily co-use	−0.097	−0.107	−0.088	.005	<.001
# marijuana * daily co-use						−0.010	−0.016	−0.005	.003	<.001

Note. AUDIT= Alcohol Use Disorders Identification Test; CUDIT-R=Cannabis use Disorder Identification Test Revised. ICCs for subject-level clustering of subjective intoxication were .30 and .39, respectively, in data comparing co-use to alcohol only (left panel) and marijuana only (right panel).