Table 1.

Patterns of polysubstance use characterized by past-year use of tobacco, cannabis, cocaine, or other illicit drugs among NESARC respondents with alcohol dependence at Wave 1 (n = 1,172)

Past-year use (Wave 1)	Alcohol Use Only (n= 351)		Alcohol and Tobacco Use (n= 402)		Alcohol, Tobacco and Cannabis Use (n= 171)		Alcohol, Tobacco Cannabis, Cocaine and other Illicit Drug Use illicit drug(s) (n= 248)
	%	95% CI	%	95% CI	%	95% CI	%	95% CI
Weighted Percentages	27.5	[24.2, 31.1]	32.4	[28.8, 36.2]	14.8	[12.6, 17.4]	25.3	[21.7, 29.2]
Tobacco use	0	[0, 0]	100	[100.0, 100.0]	76.8	[68.8, 83.3]	76.8	[69.1, 83.0]
Cannabis use	0	[0, 0]	0	[0, 0]	100	[100, 100]	73.6	[66.9, 79.4]
Cocaine use	0	[0, 0]	1.8	[0.8, 4.3]	8.3	[4.5, 14.9]	26.9	[20.4, 34.5]
Other illicit drug use	0	[0, 0]	0	[0, 0]	0	[0]	100	[100, 100]

Note: The four patterns of polysubstance use are identified by latent class analysis of four binary indicators for the past-year use of tobacco, cannabis, cocaine, and other illicit drugs, by allocating persons to their modal class (i.e., the class in which a person has the highest posterior probability), where pattern 1 is a known class (i.e., class membership is assumed, a priori, for persons who had no use of substances other than alcohol).