6. Early Marijuana Use and Later Drug Use Patterns - Initiation of Marijuana Use: Trends, Patterns, and Implications Report

In addition to providing useful information for prevention planning, incidence data can be used to help policymakers anticipate future trends in the nature and extent of the need for substance abuse treatment services. Marijuana incidence data have been used to make projections of drug abuse treatment need in the year 2020 (Gfroerer & Epstein, 1999). That study and others have shown the importance of early marijuana use as a predictor of later substance use patterns and associated problems (Brook, Gordon, Brook, & Cohen, 1989; Brook, Cohen, & Brook, 1998b; Brook et al., 1999b; DeWit, Hance, Offord, & Ogborne, 2000; Grant & Dawson, 1998). Given the substantial increases in marijuana incidence rates during the 1990s and the continuing high rates as recently as 1999, data showing the relationship between early initiation and later substance use patterns are needed. This chapter provides such data, primarily focusing on age at first use of marijuana as a predictor.

The remainder of this chapter focuses on three topics. Section 6.2 discusses the estimated proportions of drug use patterns among adults aged 26 or older by age at first marijuana use and by age groups. Section 6.3 provides adjusted odds ratios (ORs) of illicit drug use, heavy illicit drug use, and substance dependence/abuse from the multiple logistic regression models. Each logistic regression model includes age of marijuana initiation, age group, gender, race/ethnicity, and educational level. Section 6.4 includes findings for a subset of the analysis focusing on past year marijuana users aged 26 or older. This subset examined the relationship between age at first marijuana use and past year drug dependence (e.g., marijuana dependence, illicit drug dependence other than marijuana, illicit drug dependence, alcohol dependence or abuse, and alcohol or illicit drug dependence/abuse).

Heavy marijuana use was defined as using marijuana on at least 300 days in the past year. Heavy illicit drug use other than marijuana was defined as using at least one of the following: cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically on at least 50 days in the past year, regardless of marijuana/hashish use. Marijuana/hashish users who also had used any of the other listed drugs on at least 50 days in the past year were counted as heavy users of illicit drugs other than marijuana. Because of changes in the measures of dependence and abuse in the 2000 survey, estimates for alcohol or illicit drug abuse and dependence were based only on data from the 2000 survey. In brief, the 2000 NHSDA includes a series of questions on dependence that assess health or emotional problems, attempts to cut down on use, tolerance, withdrawal, and other symptoms associated with substances used. The questions on abuse assess problems at work, home, and school; problems with family or friends; physical danger; and trouble with the law due to substances used. The changes in measures of abuse and dependence limit the comparisons between 2000's estimates and estimates from prior surveys.

6.2 Estimated Prevalence of Illicit Drug Use, Heavy Illicit Drug Use, Substance Abuse, and Dependence, by Age of Marijuana Initiation

The prevalence of lifetime and past year use of heroin, cocaine, and nonmedical psychotherapeutics in relation to age at first marijuana use is presented in Table 6.1 and Figure 6.1. Among adults aged 26 or older, the highest prevalence of use of heroin, cocaine, and psychotherapeutics in the lifetime was noted among those who initiated marijuana before they were 15 years old (9.2, 62.0, and 53.9 percent, respectively, for heroin, cocaine, and psychotherapeutics). There was a tendency for the prevalence of lifetime illicit drug use to decrease with older age of first marijuana use. Among lifetime marijuana users reporting their onset after age 20, an estimated 1.1 percent used heroin, 16.4 percent used cocaine, and 20.6 percent used any psychotherapeutics nonmedically in their lifetime. Among persons who had never used marijuana, less than 1 percent had ever used cocaine or heroin, but 5.1 percent had used psychotherapeutics nonmedically.

Similar patterns of past year use of these illicit drugs across the four groups of age at first marijuana use were observed. An estimated 6.9 percent of early-onset marijuana users (onset at age 14 or younger) used cocaine in the past year compared with only 0.8 percent of those initiating after age 20. An estimated 11.5 percent of early-onset marijuana users (onset at age 14 or younger) used any psychotherapeutics in the past year, while 2.9 percent of those initiating after age 20 did so.

For marijuana users aged 26 to 34 and those aged 35 to 49, rates of lifetime illicit drug use were generally higher among adolescence-onset marijuana users than among users initiating during adulthood. Because of a low prevalence of other illicit drug use among marijuana users aged 50 or older and very low proportions of past year heroin use across all three age groups (less than 1 percent), the relationship between the use of these illicit drugs and the onset age of marijuana use was less clear for them.

Figure 6.1 Prevalence of Lifetime Use of Heroin, Cocaine, and Psychotherapeutics among Adults Aged 26 or Older, by Age of Marijuana Initiation: 1999 and 2000

Note: Nonmedical use of any prescription-type psychotherapeutic indicates using pain relievers, tranquilizers, stimulants, or sedatives at least once. Indicated use does not include over-the-counter drugs.

Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Among all lifetime marijuana users aged 26 or older, early-onset users not only had relatively higher proportions of recent (past year) heavy marijuana use than adult-onset users, but they also reported high proportions of heavy use of other illicit drugs (Table 6.2 and Figure 6.2). An estimated 5.0 percent of those initiating marijuana at age 14 or younger were recent heavy marijuana users compared with less than 1 percent of those with an onset age of 18 years or older. Likewise, 6.3 percent of those initiating marijuana at age 14 or younger were recent heavy users of other illicit drugs in comparison with about 1 percent of those with an onset age of 18 years or older. A similar pattern also was observed among two age groups of marijuana users (i.e., adults aged 26 to 34 and those aged 35 to 49). There was an insufficient number of heavy illicit drug users among the older age group (i.e., aged 50 or older) to allow for such a comparison. Less than 1 percent of adults who had never used marijuana reported heavy use of other illicit drugs.

Figure 6.2 Prevalence of Past Year Heavy Marijuana Use and Heavy Use of Other Illicit Drugs among Adults Aged 26 or Older, by Age of Marijuana Initiation: 1999 and 2000

Note: Heavy marijuana use refers to using marijuana on 300 or more days in the past year. Heavy use of other illicit drugs refers to using cocaine, hallucinogens, inhalants, heroin, or any prescription-type psychotherapeutic used nonmedically (i.e., pain relievers, sedatives, tranquilizers, or stimulants) on at least 50 days in the past year.

Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

The estimated past year prevalence of dependence on and abuse of alcohol or illicit drugs by age at first use of marijuana is summarized in Table 6.3 and Figure 6.3. Overall and among those aged 26 to 49, prevalence rates of dependence on or abuse of an illicit drug and prevalence rates of dependence on or abuse of either alcohol or an illicit drug were highest among those who started to use marijuana at age 14 or younger. An estimated 6.2 percent of those initiating marijuana before age 15 abused or were dependent on an illicit drug in the past year compared with 1.3 percent of those initiating marijuana at age 21 or older. Similarly, 18.0 percent of early-onset (onset before age 15) marijuana users were classified with dependence on or abuse of either alcohol or an illicit drug in comparison with 7.6 percent of those who first used marijuana after age 20.

Even when the prevalence was restricted to dependence and was specific to alcohol, an illicit drug, marijuana, or an illicit drug other than marijuana, prevalence rates of dependence for each outcome were consistently found to be highest among marijuana users who started their first use at age 14 or younger.

Among adults who had never used marijuana, the prevalence of past year alcohol and/or illicit drug abuse or dependence was very low. Only about 0.2 percent of them were classified with dependence on or abuse of an illicit drug and 0.9 percent were dependent on alcohol. In addition, there was a tendency among those who had never used marijuana for the prevalence of illicit drug abuse or dependence to be higher among young adults aged 26 to 34 years (0.4 percent), but for the prevalence of alcohol dependence to be slightly higher among persons aged 35 to 49 (1.4 percent).

Figure 6.3 Prevalence of Past Year Alcohol and/or Illicit Drug Dependence or Abuse among Adults Aged 26 or Older, by Age of Marijuana Initiation: 2000

Note: Illicit drug dependence or abuse indicates dependence on or abuse of at least one of the following drugs: marijuana/hashish, cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically. The alcohol-only data refer to just dependence on alcohol, not alcohol abuse. Dependence or abuse is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (APA, 1994).

Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

The estimated strength of associations of age at first marijuana use with the use of other illicit drugs and/or recent substance dependence and abuse was determined via multiple logistic regression procedures. Each logistic regression model also included age, gender, race/ethnicity, and educational level. Adjusted ORs, denoting the estimated association, that were derived from the multiple logistic regression procedures are discussed in this section.

6.3.1 Adjusted Odds Ratios of Use of Heroin, Cocaine, and Psychotherapeutics Nonmedically

Adjusted ORs for use of heroin, cocaine, and psychotherapeutics among lifetime marijuana users aged 26 or older are displayed in Table 6.4 (lifetime use) and Table 6.5 (past year use).

With statistical adjustment for demographic characteristics, age at onset of marijuana use was significantly associated with lifetime heroin use (Table 6.4). In particular, onset before age 15 strongly predicted lifetime heroin use. Adjusted ORs of ever using heroin among lifetime marijuana users were 15.5 for those reporting first marijuana use at age 14 or younger, 6.1 for those initiating between the ages of 15 and 17, and 3.5 for those initiating between the ages of 18 and 20 as compared with those experiencing onset at age 21 or older. Among marijuana users, younger adults were significantly less likely to have ever used heroin than older adults aged 50 or older (OR = 0.2 for adults aged 26 to 34; OR = 0.5 for adults aged 35 to 49). Male marijuana users were an estimated 1.6 times more likely than female users to have ever used heroin. Relative to blacks, whites were at lower odds of using heroin in the lifetime. Educational level was not found to be associated with odds of lifetime heroin use. Age at first marijuana use was not associated with past year heroin use in the adjusted logistic regression model (Table 6.5).

Age at onset of marijuana use was highly associated with lifetime and recent cocaine use, particularly for those who initiated before age 15. These persons were 7 to 8 times more likely than those who initiated at age 21 or older to use cocaine (Tables 6.4 and 6.5). Lifetime marijuana users who were male and American Indian or Alaska Native (relative to black) also had increased rates of lifetime cocaine use. The analysis of recent cocaine use found that male gender and less than a high school education predicted increased odds of using cocaine in the past year (Table 6.5). In addition, white and Asian/Pacific Islander/Native Hawaiian lifetime marijuana users were less likely than black users to use cocaine recently.

Early onset of marijuana use also predicted increased odds of nonmedical use of any psychotherapeutic drug in the lifetime and past year (OR = 5.3 for lifetime use; OR = 3.4 for past year use). Younger adult marijuana users (aged 26 to 34) were less likely than older users (aged 50 or older) to report using psychotherapeutics in the lifetime, but they were significantly more likely to use them in the past year. Male marijuana users had decreased odds of using psychotherapeutics in the past year (OR = 0.8). Compared with black marijuana users, white, Hispanic, and American Indian/Alaska Native users had increased odds of recent psychotherapeutic use. Persons with less than high school schooling also had an increased likelihood of using psychotherapeutics in the past year.

Adjusted ORs of past year (recent) heavy illicit drug use (marijuana and other illicit drugs) are summarized in Table 6.6. Early-onset of marijuana use (before age 15) was significantly associated with the increased odds of heavy use of marijuana (OR = 5.3) and other illicit drugs (OR = 4.5). Marijuana initiation between the ages of 15 and 17 also predicted heavy use of other illicit drugs (OR = 2.1). Male marijuana users were an estimated 2.1 times more likely than female users to report heavy marijuana in the past year. Lifetime marijuana users who did not attend college also were at increased odds of using an illicit drug heavily in the past year.

This section includes results of multiple logistic regression analyses of the following outcomes in relation to age at first use of marijuana among lifetime marijuana users aged 26 or older (Tables 6.7 to 6.9): (1) illicit drug dependence or abuse, (2) alcohol or illicit drug dependence or abuse, (3) alcohol dependence, (4) illicit drug dependence, (5) marijuana dependence, and (6) other illicit drug dependence.

Onset of marijuana use before age 15 significantly predicted increased odds of meeting the criteria for dependence on and/or abuse of either alcohol and/or an illicit drug in the past year (OR = 4.7 for an illicit drug; OR = 1.9 for alcohol or other illicit drugs). Black marijuana users had an increased likelihood of being dependent on or abusing an illicit drug than white and Asian/Pacific Islander/Native Hawaiian users. Less educated lifetime marijuana users (less than high school) were an estimated 1.8 times more likely to be classified with dependence on or abuse of an illicit drug recently, while age and gender were not associated with any odds of being dependent on or abusing illicit drugs (Table 6.7). Lifetime marijuana users who were aged 26 to 34, male, or had not attended college at the time of the survey had slightly increased odds of being dependent on or abusing alcohol or an illicit drug in the past year.

Adjusted ORs of alcohol dependence and illicit drug dependence among lifetime marijuana users are shown in Table 6.8. Age at marijuana initiation, age, and race/ethnicity were not found to predict recent alcohol dependence. In comparison, male and less educated marijuana users were at increased odds of being alcohol dependent in the past year. When the outcome of the logistic regression model was specific to illicit drug dependence, early-onset marijuana users (before age 15) were an estimated 6.2 times more likely than adult-onset users to be dependent on one or more illicit drugs in the past year. Relative to black marijuana users, white, Asian/Pacific Islander/Native Hawaiian, and American Indian or Alaska Native users had decreased odds of being classified with illicit drug dependence.

Table 6.9 further examines the estimated association between the onset age of marijuana use and recent illicit drug dependence. The multiple regression procedures revealed that the onset of marijuana use before age 15 was associated with recent dependence on both marijuana and other illicit drugs. In fact, onset before age 15 was associated with close to a tenfold excess in the odds of being classified with marijuana dependence than those who initiated marijuana in adulthood, independent of the influences of age, gender, race/ethnicity, and educational level. Marijuana users with less than a high school education were 3 times more likely than those who had attended college to be dependent on other illicit drugs recently.

This section focuses on dependence on and abuse of substances among lifetime marijuana users aged 26 or older who also used marijuana in the past year. The analyses presented in Section 6.3 demonstrate a high correlation between age at first marijuana use and subsequent patterns of substance use among adults aged 26 or older. Early-onset marijuana users are clearly more likely than adult-onset users to use drugs heavily and to have dependence and abuse problems later in life. However, these results do not indicate whether the higher rate of problematic use is simply because early-onset users are more likely to continue using illicit drugs as they age, making them more susceptible to problems, or whether their use of marijuana at a young age is a predictor of problematic use independent of their use history. Although it is not possible to fully explore this question with the limited data available in the NHSDA on drug use history, some indication of the independent effect of age at first use can be obtained by restricting analyses to persons who used marijuana in the past year.

6.4.1 Estimated Prevalence of Illicit Drug Dependence and/or Abuse, by Age of Marijuana Initiation

Table 6.10 displays past year prevalence of illicit drug dependence or abuse, alcohol or illicit drug dependence or abuse, and specific substance dependence among past year marijuana users aged 26 or older. These prevalence estimates are presented by age of marijuana initiation (14 or younger, 15 to 17 years, 18 to 20 years, and 21 or older).

The highest prevalence of illicit drug dependence or abuse, alcohol or illicit drug dependence or abuse, marijuana dependence, and other illicit drug dependence was found among those in the youngest group of age of first marijuana use. Among past year marijuana users, one fifth of those initiating marijuana before age 15 were classified with illicit drug dependence or abuse in the past year compared with approximately one tenth of those initiating marijuana after age 15. Similarly, about 40 percent of those with their onset of marijuana before age 14 met the criteria for dependence on or abuse of either alcohol or other illicit drugs compared with 16.7 percent of those with an onset after age 20.

With respect to alcohol dependence, approximately 10 percent of users with an onset of marijuana use before age 21 were dependent on alcohol in comparison with about 5 percent of those with an onset after age 20. The highest prevalence (15.2 percent) of illicit drug dependence was noted among those initiating use before age 15, while the lowest prevalence (3.4 percent) of illicit drug dependence was among those reporting their first use after age 20. Approximately 8 percent of those with an onset between ages 15 and 20 were dependent on an illicit drug.

Only 2.1 percent of those with their onset of marijuana after age 20 were dependent on marijuana in the past year, while 8.8 percent of those within the 14 or younger group, 4.7 percent of those within the 15 to 17 onset group, and 7.1 percent of those within the 18 to 20 onset group were dependent on marijuana. The prevalence of other illicit drug dependence decreased with increased age strata of first marijuana use. An estimated 8.6 percent of those with an onset before age 15 and 4.2 percent of those with an onset between the ages of 15 and 17 were dependent on other illicit drugs in the past year, while less than 3.0 percent of those with an onset at age 18 or older were classified with other illicit drug dependence.

The association between age at first use of marijuana and substance dependence and/or abuse among past year marijuana users aged 26 or older was examined using multiple logistic regression procedures. Adjusted ORs denote the estimated strength, holding constant the potential confounding influence of other demographic characteristics. Table 6.11 summarizes the logistic regression models for two dependence/abuse outcomes: (a) illicit drug dependence or abuse and (b) alcohol or illicit drug dependence or abuse. Models for alcohol dependence and illicit drug dependence are displayed in Table 6.12. Finally, models for marijuana dependence and other illicit drug dependence are shown in Table 6.13.

With statistical adjustment for demographic characteristics, onset of marijuana use before age 18 predicted increased odds of being classified with dependence on or abuse of either alcohol or other illicit drugs among adult marijuana users who reported the use in the past year (Table 6.11). Relative to an onset of marijuana use after age 20, an onset of use between the ages of 18 and 20 was not significant in predicting recent substance dependence or abuse. Compared with black marijuana users, white users were at decreased odds of meeting the criteria for illicit drug dependence or abuse in the past year (OR = 0.5). Recent marijuana users with a high school diploma had decreased odds of illicit drug dependence or abuse when compared with users who attended college.

Among recent marijuana users, age at onset of marijuana use was not found to be associated with alcohol dependence in the model (Table 6.12). In comparison, an onset of marijuana use before age 21 was associated with an increased likelihood of being classified with illicit drug dependence as compared with users with an onset at age 21 or older. Those with an onset before age 15 were an estimated 8.3 times more likely than those with an onset after age 20 to be dependent on one or more illicit drugs. Those with an onset between the ages of 15 and 20 were about 3 times more likely than those with an onset after age 20 to be dependent on one or more illicit drugs. As noted in the finding for illicit drug dependence or abuse, white recent marijuana users were less likely than black users to be dependent on an illicit drug (OR = 0.4).

Finally, multiple logistic regression showed that, among adult recent marijuana users, early-onset of marijuana use increased the likelihood of being dependent on both marijuana and other illicit drugs (Table 6.13). Relative to those with an onset of marijuana use after age 20, those reporting an onset before age 15 had an estimated OR of 5.1 for marijuana dependence and an OR of 17.0 for other illicit drug dependence. In addition, recent marijuana users aged 50 years old or older and black users were more likely to be classified with dependence on other illicit drugs than younger and white recent marijuana users.

*Table 6.1 Percentages with Lifetime and Past Year Use of Heroin, Cocaine, and Psychotherapeutics* among Adults Aged 26 or Older, by Age at First Marijuana Use and Age Groups: 1999 and 2000**
Age in Years	Age of Marijuana Initiation in Years	Heroin		Cocaine		Any Psychotherapeutic
Age in Years	Age of Marijuana Initiation in Years	Lifetime	Past Year	Lifetime	Past Year	Lifetime	Past Year
Total	14 or younger	9.2	0.6	62.0	6.9	53.9	11.5
	15-17	4.2	0.2	40.9	3.5	36.5	5.6
	18-20	3.0	0.1	28.8	1.8	26.6	3.9
	21 or older	1.1	0.2	16.4	0.8	20.6	2.9
	Never used marijuana	0.1	0.0	0.6	0.1	5.1	1.2
26-34	14 or younger	5.1	0.1	57.5	8.9	48.6	12.3
	15-17	2.3	0.3	34.5	4.5	29.8	7.0
	18-20	1.2	0.1	19.4	2.4	19.4	5.1
	21 or older	0.5	0.0	14.9	1.5	17.4	5.0
	Never used marijuana	0.1	0.0	1.0	0.1	6.6	1.8
35-49	14 or younger	11.6	1.0	65.7	5.2	57.7	10.9
	15-17	4.8	0.2	44.3	3.0	39.8	5.1
	18-20	3.0	0.1	32.2	1.5	27.6	3.4
	21 or older	0.8	0.5	20.2	1.4	20.5	3.3
	Never used marijuana	0.1	0.0	1.2	0.1	6.2	6.2
50+	17 or younger	13.4	0.0	37.4	6.0	38.5	4.1
	18-20	5.8	0.2	29.6	2.0	33.2	4.0
	21 or older	1.5	0.0	14.1	0.2	21.5	2.1
	Never used marijuana	0.0	0.0	0.2	0.0	4.1	1.0
Note: Nonmedical use of any prescription-type psychotherapeutic indicates using pain relievers, tranquilizers, stimulants, or sedatives at least once. Indicated use does not include over-the-counter drugs. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

*Table 6.2 Percentages with Past Year Heavy Marijuana Use and Heavy Use of Other Illicit Drugs* among Adults Aged 26 or Older, by Age at First Marijuana Use and Age Groups: 1999 and 2000**
Age in Years	Age of Marijuana Initiation in Years	Heavy Marijuana Use	Heavy Use of Other Illicit Drugs
Total	14 or younger	5.0	6.3
	15-17	1.2	2.8
	18-20	0.6	1.4
	21 or older	0.5	1.1
	Never used marijuana	0.0	0.5
26-34	14 or younger	7.3	7.0
	15-17	1.7	3.2
	18-20	1.3	1.3
	21 or older	0.5	1.8
	Never used marijuana	0.0	0.6
35-49	14 or younger	3.5	5.5
	15-17	1.0	2.6
	18-20	0.4	1.6
	21 or older	0.7	1.7
	Never used marijuana	0.0	0.6
50+	17 or younger	0.0	6.1
	18-20	0.2	0.9
	21 or older	0.4	0.5
	Never used marijuana	0.0	0.4
Note: Heavy marijuana use refers to using marijuana on 300 or more days in the past year. Heavy use of other illicit drugs refers to using cocaine, hallucinogens, inhalants, heroin, or any prescription-type psychotherapeutic used nonmedically (i.e., pain relievers, sedatives, tranquilizers, or stimulants) on at least 50 days in the past year. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

*Table 6.3 Percentages with Past Year Alcohol and/or Illicit Drug Dependence or Abuse* among Adults Aged 26 or Older, by Age at First Marijuana Use and Age Groups: 2000**
Age in Years	Age of Marijuana Initiation in Years	Illicit Drug Dependence or Abuse	Alcohol or Illicit Drug Dependence or Abuse	Alcohol Dependence	Illicit Drug Dependence	Marijuana Dependence	Other Illicit Drug Dependence
Total	14 or younger	6.2	18.0	6.8	4.5	2.5	2.7
	15-17	2.2	9.5	3.6	1.4	0.7	0.9
	18-20	2.0	8.3	3.5	1.7	0.8	1.2
	21 or older	1.3	7.6	3.2	0.7	0.2	0.5
	Never used marijuana	0.2	2.1	0.9	0.1	0.0	0.1
26-34	14 or younger	7.7	19.2	6.7	5.7	3.3	3.2
	15-17	2.9	13.1	4.1	1.7	0.8	1.1
	18-20	1.8	11.4	4.3	1.3	0.9	0.5
	21 or older	3.0	13.7	4.0	0.7	0.6	0.1
	Never used marijuana	0.4	3.4	1.0	0.2	0.0	0.2
35-49	14 or younger	5.0	17.3	6.5	3.4	2.0	2.0
	15-17	1.7	7.8	3.5	1.4	0.7	0.8
	18-20	1.8	7.5	3.2	1.7	0.8	1.1
	21 or older	1.7	8.0	3.8	1.2	0.0	1.2
	Never used marijuana	0.2	2.6	1.4	0.1	0.0	0.1
50+	17 or younger	8.2	9.8	4.6	3.6	0.0	3.6
	18-20	2.8	7.2	3.4	2.1	0.4	2.1
	21 or older	0.6	5.7	2.7	0.4	0.2	0.2
	Never used marijuana	0.1	1.4	0.6	0.1	0.0	0.1
Note: Illicit drug dependence or abuse indicates dependence on or abuse of at least one of the following drugs: marijuana/hashish, cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically. Other illicit drug dependence indicates meeting the dependence criteria of at least one of the following drugs: cocaine, hallucinogens, inhalants, heroin, pain relievers, sedatives, tranquilizers, or stimulants. Dependence or abuse is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

*Table 6.4 Adjusted Odds Ratios of Lifetime Use of Heroin, Cocaine, and Psychotherapeutics* among Lifetime Marijuana Users Aged 26 or Older: 1999 and 2000**
Variables	Lifetime Heroin Use				Lifetime Cocaine Use				Lifetime Psychotherapeutic Use
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	15.45	(7.56	-	31.55)	7.95	(6.53	-	9.68)	5.25	(4.37	-	6.31)
15-17 vs. 21 or older	6.10	(2.95	-	12.58)	3.27	(2.76	-	3.87)	2.47	(2.09	-	2.92)
18-20 vs. 21 or older	3.53	(1.73	-	7.20)	1.88	(1.57	-	2.25)	1.49	(1.24	-	1.78)
Age in Years
26-34 vs. 50 or older	0.22	(0.13	-	0.38)	0.91	(0.73	-	1.12)	0.63	(0.51	-	0.77)
35-49 vs. 50 or older	0.53	(0.30	-	0.91)	1.41	(1.14	-	1.74)	0.93	(0.76	-	1.12)
Gender
Male vs. female	1.61	(1.21	-	2.13)	1.33	(1.21	-	1.46)	1.04	(0.94	-	1.14)
Race/Ethnicity
White vs. black	0.43	(0.29	-	0.64)	1.12	(0.93	-	1.34)	1.78	(1.48	-	2.13)
Hispanic vs. black	0.65	(0.38	-	1.12)	1.14	(0.88	-	1.48)	1.20	(0.92	-	1.58)
Other¹ vs. black	0.52	(0.23	-	1.16)	--	(--	-	--)	--	(--	-	--)
Asian/Pacific Islander/Native Hawaiian vs. black	--	(--	-	--)	0.60	(0.38	-	0.95)	0.73	(0.45	-	1.19)
American Indian or Alaska Native vs. black	--	(--	-	--)	1.82	(1.13	-	2.93)	2.85	(1.75	-	4.66)
More than one race vs. black	--	(--	-	--)	1.19	(0.67	-	2.10)	1.57	(0.94	-	2.61)
Education
Less than high school vs. at least some college	1.44	(0.96	-	2.17)	1.04	(0.88	-	1.21)	0.93	(0.79	-	1.10)
High school graduate vs. at least some college	1.03	(0.77	-	1.38)	0.90	(0.80	-	1.00)	0.91	(0.82	-	1.02)
-- Not available. Note: Nonmedical use of any prescription-type psychotherapeutic indicates using pain relievers, tranquilizers, stimulants, or sedatives at least once. Indicated use does not include over-the-counter drugs. ¹ Asian/Pacific Islander/Native Hawaiian, American Indian/Alaska Native, and more than one race. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

*Table 6.5 Adjusted Odds Ratios of Past Year Use of Heroin, Cocaine, and Psychotherapeutics* among Lifetime Marijuana Users Aged 26 or Older: 1999 and 2000**
Variables	Past Year Heroin Use				Past Year Cocaine Use				Past Year Psychotherapeutic Use
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	2.46	(0.54	-	11.28)	7.01	(3.60	-	13.66)	3.44	(2.37	-	5.00)
15-17 vs. 21 or older	0.91	(0.21	-	3.96)	3.81	(1.99	-	7.31)	1.67	(1.19	-	2.34)
18-20 vs. 21 or older	0.56	(0.10	-	3.09)	2.04	(1.02	-	4.09)	1.26	(0.85	-	1.87)
Age in Years
26-34 vs. 50 or older	2.12	(0.23	-	19.96)	1.87	(0.83	-	4.23)	1.75	(1.04	-	2.93)
35-49 vs. 50 or older	6.04	(0.71	-	51.38)	1.19	(0.51	-	2.78)	1.33	(0.81	-	2.20)
Gender
Male vs. female	0.60	(0.26	-	1.41)	1.35	(1.03	-	1.76)	0.76	(0.63	-	0.92)
Race/Ethnicity
White vs. black	0.55	(0.20	-	1.52)	0.54	(0.39	-	0.76)	1.62	(1.18	-	2.24)
Hispanic vs. black	--	(--	-	--)	0.74	(0.43	-	1.29)	1.86	(1.13	-	3.07)
Other¹ vs. black	1.51	(0.40	-	5.78)	--	(--	-	--)	--	(--	-	--)
Asian/Pacific Islander/Native Hawaiian vs. black	--	(--	-	--)	0.23	(0.07	-	0.76)	0.65	(0.27	-	1.55)
American Indian or Alaska Native vs. black	--	(--	-	--)	1.56	(0.57	-	4.27)	3.23	(1.25	-	8.34)
More than one race vs. black	--	(--	-	--)	0.81	(0.32	-	2.06)	0.99	(0.42	-	2.29)
Education
Less than high school vs. at least some college	1.74	(0.60	-	5.03)	2.29	(1.54	-	3.40)	1.78	(1.33	-	2.39)
High school graduate vs. at least some college	0.93	(0.36	-	2.35)	1.28	(1.00	-	1.64)	1.10	(0.90	-	1.35)
-- Not available. Note: For past year heroin use, three racial/ethnic categories were used: white; black; and Hispanic, American Indian/Alaska Native, Asian/Pacific Islander/Native Hawaiian, and more than one race. Black was used as the reference group. Nonmedical use of any prescription-type psychotherapeutic indicates using pain relievers, tranquilizers, stimulants, or sedatives at least once. Indicated use does not include over-the-counter drugs. ¹ Hispanic, Asian/Pacific Islander/Native Hawaiian, American Indian/Alaska Native, and more than one race. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

*Table 6.6 Adjusted Odds Ratios of Past Year Heavy Marijuana Use and Heavy Use of Other Illicit Drugs* among Lifetime Marijuana Users Aged 26 or Older: 1999 and 2000**
Variables	Heavy Marijuana Use				Heavy Use of Other Illicit Drugs
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	5.30	(2.43	-	11.56)	4.49	(2.56	-	7.87)
15-17 vs. 21 or older	1.36	(0.63	-	2.95)	2.12	(1.24	-	3.64)
18-20 vs. 21 or older	0.82	(0.32	-	2.13)	1.15	(0.62	-	2.11)
Age in Years
26-34 vs. 50 or older	4.73	(1.33	-	16.83)	1.72	(0.83	-	3.55)
35-49 vs. 50 or older	2.31	(0.64	-	8.29)	1.52	(0.75	-	3.08)
Gender
Male vs. female	2.12	(1.47	-	3.05)	1.11	(0.86	-	1.42)
Race/Ethnicity
White vs. black	1.25	(0.77	-	2.02)	0.62	(0.42	-	0.91)
Hispanic vs. black	1.01	(0.53	-	1.95)	1.23	(0.69	-	2.18)
Other¹ vs. black	1.17	(0.45	-	3.01)	--	(--	-	--)
Asian/Pacific Islander/Native Hawaiian vs. black	--	(--	-	--)	0.54	(0.21	-	1.40)
American Indian or Alaska Native vs. black	--	(--	-	--)	2.63	(1.06	-	6.54)
More than one race vs. black	--	(--	-	--)	0.77	(0.26	-	2.29)
Education
Less than high school vs. at least some college	2.43	(1.47	-	3.99)	2.99	(2.02	-	4.41)
High school graduate vs. at least some college	2.74	(1.24	-	2.43)	1.57	(1.15	-	2.13)
-- Not available. Note: For heavy marijuana use, four racial/ethnic categories were used: white; black; Hispanic; and American Indian/Alaska Native, Pacific Islander/Native Hawaiian, and more than one race. Black was used as the reference group. Heavy marijuana use refers to using marijuana on 300 or more days in the past year. Heavy use of other illicit drugs refers to using cocaine, hallucinogens, inhalants, heroin, or any prescription-type psychotherapeutic used nonmedically (i.e., pain relievers, sedatives, tranquilizers, or stimulants) on at least 50 days in the past year. ¹ Asian/Pacific Islander/Native Hawaiian, American Indian/Alaska Native, and more than one race. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

*Table 6.7 Adjusted Odds Ratios of Past Year Illicit Drug Dependence or Abuse and Alcohol or Illicit Drug Dependence or Abuse* among Lifetime Marijuana Users Aged 26 or Older: 2000**
Variables	Illicit Drug Dependence or Abuse				Alcohol or Illicit Drug Dependence or Abuse
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	4.74	(1.86	-	12.08)	1.90	(1.33	-	2.72)
15-17 vs. 21 or older	1.74	(0.69	-	4.36)	0.99	(0.71	-	1.37)
18-20 vs. 21 or older	1.51	(0.61	-	3.72)	0.94	(0.67	-	1.32)
Age in Years
26-34 vs. 50 or older	1.31	(0.44	-	3.95)	2.20	(1.41	-	3.43)
35-49 vs. 50 or older	0.88	(0.31	-	2.52)	1.43	(0.92	-	2.22)
Gender
Male vs. female	1.12	(0.72	-	1.74)	1.94	(1.56	-	2.42)
Race/Ethnicity
White vs. black	0.52	(0.30	-	0.88)	0.93	(0.70	-	1.25)
Hispanic vs. black	0.89	(0.45	-	1.75)	0.95	(0.62	-	1.47)
Asian/Pacific Islander/Native Hawaiian vs. black	0.13	(0.03	-	0.63)	0.79	(0.27	-	2.28)
American Indian or Alaska Native vs. black	0.96	(0.26	-	3.46)	1.36	(0.59	-	3.13)
More than one race vs. black	3.01	(0.85	-	10.74)	1.59	(0.54	-	4.67)
Education
Less than high school vs. at least some college	1.81	(1.05	-	3.13)	1.91	(1.42	-	2.56)
High school graduate vs. at least some college	0.75	(0.51	-	1.10)	1.32	(1.07	-	1.63)
Note: Illicit drug dependence or abuse indicates dependence on or abuse of at least one of the following drugs: marijuana/hashish, cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically. Dependence or abuse is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

*Table 6.8 Adjusted Odds Ratios of Past Year Alcohol Dependence and Illicit Drug Dependence* among Lifetime Marijuana Users Aged 26 or Older: 2000**
Variables	Alcohol Dependence				Illicit Drug Dependence
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	1.64	(0.91	-	2.95)	6.19	(2.22	-	17.21)
15-17 vs. 21 or older	0.97	(0.57	-	1.65)	1.98	(0.74	-	5.27)
18-20 vs. 21 or older	1.02	(0.56	-	1.84)	2.29	(0.79	-	6.64)
Age in Years
26-34 vs. 50 or older	1.51	(0.75	-	3.03)	1.20	(0.36	-	4.00)
35-49 vs. 50 or older	1.33	(0.67	-	2.64)	0.99	(0.30	-	3.30)
Gender
Male vs. female	1.72	(1.23	-	2.41)	1.00	(0.61	-	1.64)
Race/Ethnicity
White vs. black	0.83	(0.50	-	1.36)	0.49	(0.26	-	0.91)
Hispanic vs. black	0.67	(0.34	-	1.33)	0.57	(0.22	-	1.44)
Asian/Pacific Islander/Native Hawaiian vs. black	1.15	(0.23	-	5.64)	0.17	(0.03	-	0.87)
American Indian/Alaska Native vs. black	0.96	(0.23	-	3.99)	0.27	(0.08	-	0.95)
More than one race	0.81	(0.24	-	2.77)	1.09	(0.30	-	3.97)
Education
Less than high school vs. at least some college	3.34	(2.21	-	5.07)	1.81	(0.90	-	3.62)
High school graduate vs. at least some college	1.62	(1.15	-	2.30)	0.69	(0.43	-	1.12)
Note: Illicit drug dependence indicates dependence on at least one of the following drugs: marijuana/hashish, cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically. Dependence is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

*Table 6.9 Adjusted Odds Ratios of Past Year Marijuana Dependence and Other Illicit Drug Dependence* among Lifetime Marijuana Users Aged 26 or Older: 2000**
Variables	Marijuana Dependence				Other Illicit Drug Dependence
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	9.77	(2.82	-	33.89)	5.67	(1.51	-	21.29)
15-17 vs. 21 or older	2.67	(0.76	-	9.38)	1.94	(0.56	-	6.74)
18-20 vs. 21 or older	2.98	(0.79	-	11.25)	2.52	(0.64	-	9.94)
Age in Years
26-34 vs. 50 or older	2.47	(0.69	-	8.83)	0.76	(0.19	-	3.14)
35-49 vs. 50 or older	1.70	(0.46	-	6.27)	0.80	(0.19	-	3.33)
Gender
Male vs. female	1.31	(0.71	-	2.40)	0.83	(0.44	-	1.56)
Race/Ethnicity
White vs. black	0.52	(0.21	-	1.31)	0.53	(0.24	-	1.16)
Hispanic vs. black	--	(--	-	--)	0.80	(0.27	-	2.35)
Other¹ vs. black	0.47	(0.12	-	1.77)	--	(--	-	--)
Other² vs. black	--	(--	-	--)	0.70	(0.20	-	2.50)
Education
Less than high school vs. at least some college	0.95	(0.41	-	2.24)	2.98	(1.29	-	6.89)
High school graduate vs. at least some college	0.46	(0.23	-	0.92)	1.05	(0.59	-	1.88)
-- Not available. Note: For marijuana dependence, three racial/ethnic categories were used: white; black; and Hispanic, American Indian/Alaska Native, Asian/Pacific Islander/Native Hawaiian, and more than one race. Black was used as the reference group. Other illicit drug dependence indicates meeting the dependence criteria of one or more of the following drugs: cocaine, hallucinogens, inhalants, heroin, pain relievers, sedatives, tranquilizers, or stimulants. Dependence is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). ¹ Hispanic, Asian/Pacific Islander/Native Hawaiian, American Indian/Alaska Native, and more than one race. ² Asian/Pacific Islander/Native Hawaiian, American Indian/Alaska Native, and more than one race. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

*Table 6.10 Percentages with Past Year Alcohol and/or Illicit Drug Dependence or Abuse* among Past Year Marijuana Users Aged 26 or Older, by Age at First Marijuana Use: 2000**
Age of Marijuana Initiation in Years	Illicit Drug Dependence or Abuse	Alcohol or Illicit Drug Dependence or Abuse	Alcohol Dependence	Illicit Drug Dependence	Marijuana Dependence	Other Illicit Drug Dependence
14 or younger	20.7	39.5	11.7	15.2	8.8	8.6
15-17	12.6	27.8	9.4	8.0	4.7	4.2
18-20	9.7	22.9	11.0	7.9	7.1	3.0
21 or older	7.5	16.7	5.4	3.4	2.1	1.3
Note: Illicit drug dependence or abuse indicates dependence on or abuse of at least one of the following drugs: marijuana/hashish, cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically. Other illicit drug dependence indicates meeting the dependence criteria of one or more of the following drugs: cocaine, hallucinogens, inhalants, heroin, pain relievers, sedatives, tranquilizers, or stimulants. Dependence or abuse is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

Table 6.11 Adjusted Odds Ratios of Illicit Drug Dependence or Abuse and Alcohol or Illicit Drug Dependence or Abuse among Lifetime Marijuana Users Aged 26 or Older Who Also Used Marijuana in the Past Year: 2000
Variables	Illicit Drug Dependence or Abuse				Alcohol or Illicit Drug Dependence or Abuse
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	5.69	(2.12	-	15.28)	3.63	(1.86	-	7.06)
15-17 vs. 21 or older	2.94	(1.03	-	8.36)	2.17	(1.09	-	4.32)
18-20 vs. 21 or older	1.80	(0.71	-	4.59)	1.63	(0.88	-	3.01)
Age in Years
26-34 vs. 50 or older	0.38	(0.13	-	1.09)	0.80	(0.32	-	1.97)
35-49 vs. 50 or older	0.37	(0.14	-	1.01)	0.76	(0.32	-	1.82)
Gender
Male vs. female	0.89	(0.57	-	1.39)	1.16	(0.83	-	1.63)
Race/Ethnicity
White vs. black	0.46	(0.26	-	0.80)	1.01	(0.64	-	1.59)
Hispanic vs. black	1.37	(0.59	-	3.19)	1.31	(0.65	-	2.64)
Other¹ vs. black	1.13	(0.49	-	2.62)	--	(--	-	--)
Asian/Pacific Islander/Native Hawaiian vs. black	--	(--	-	--)	0.23	(0.06	-	0.90)
American Indian/Alaska Native vs. black	--	(--	-	--)	1.24	(0.38	-	4.04)
More than one race vs. black	--	(--	-	--)	1.68	(0.56	-	5.06)
Education
Less than high school vs. at least some college	1.02	(0.62	-	1.68)	1.44	(0.91	-	2.26)
High school graduate vs. at least some college	0.62	(0.40	-	0.98)	0.92	(0.63	-	1.34)
-- Not available. Note: Illicit drug dependence or abuse indicates dependence on or abuse of at least one of the following drugs: marijuana/hashish, cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically. Dependence or abuse is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). ¹ Asian/Pacific Islander/Native Hawaiian, American Indian/Alaska Native, and more than one race. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

*Table 6.12 Adjusted Odds Ratios of Past Year Alcohol Dependence and Illicit Drug Dependence* among Lifetime Marijuana Users Aged 26 or Older Who Also Used Marijuana in the Past Year: 2000**
Variables	Alcohol Dependence				Illicit Drug Dependence
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	2.45	(0.79	-	7.63)	8.33	(2.99	-	23.19)
15-17 vs. 21 or older	2.09	(0.69	-	6.32)	3.68	(1.22	-	11.05)
18-20 vs. 21 or older	2.56	(0.94	-	6.95)	3.16	(1.06	-	9.44)
Age in Years
26-34 vs. 50 or older	0.77	(0.17	-	3.49)	0.41	(0.14	-	1.19)
35-49 vs. 50 or older	0.86	(0.19	-	3.84)	0.45	(0.15	-	1.36)
Gender
Male vs. female	1.16	(0.69	-	1.95)	0.81	(0.49	-	1.33)
Race/Ethnicity
White vs. black	1.45	(0.58	-	3.62)	0.41	(0.23	-	0.75)
Hispanic vs. black	1.61	(0.56	-	4.65)	0.68	(0.24	-	1.92)
Other¹ vs. black	1.09	(0.22	-	5.33)	0.41	(0.11	-	1.54)
Education
Less than high school vs. at least some college	2.94	(1.55	-	5.59)	0.90	(0.47	-	1.70)
High school graduate vs. at least some college	1.35	(0.76	-	2.41)	0.56	(0.32	-	1.00)
Note: Illicit drug dependence indicates dependence on at least one of the following: marijuana/hashish, cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically. Dependence is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). ¹ Asian/Pacific Islander/Native Hawaiian, American Indian/Alaska Native, and more than one race. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

*Table 6.13 Adjusted Odds Ratios of Past Year Marijuana Dependence and Other Illicit Drug Dependence* among Lifetime Marijuana Users Aged 26 or Older Who Also Used Marijuana in the Past Year: 2000**
Variables	Marijuana Dependence				Other Illicit Drug Dependence
Variables	Odds Ratio	95% Confidence Interval			Odds Ratio	95% Confidence Interval
Age at First Marijuana Use in Years
14 or younger vs. 21 or older	5.05	(1.49	-	17.15)	17.03	(3.44	-	84.16)
15-17 vs. 21 or older	2.27	(0.63	-	8.15)	7.73	(1.41	-	42.32)
18-20 vs. 21 or older	3.55	(0.90	-	14.03)	3.97	(0.72	-	21.80)
Age in Years
26-34 vs. 50 or older	1.05	(0.27	-	4.11)	0.19	(0.05	-	0.70)
35-49 vs. 50 or older	1.08	(0.26	-	4.53)	0.25	(0.06	-	1.07)
Gender
Male vs. female	0.84	(0.45	-	1.57)	0.82	(0.41	-	1.65)
Race/Ethnicity
White vs. black	0.62	(0.25	-	1.50)	0.38	(0.19	-	0.74)
Other¹ vs. black	0.58	(0.16	-	2.16)	0.83	(0.27	-	2.51)
Education
Less than high school vs. at least some college	0.75	(0.33	-	1.72)	1.69	(0.71	-	4.00)
High school graduate vs. at least some college	0.42	(0.20	-	0.85)	0.99	(0.46	-	2.16)
Note: Other illicit drug dependence indicates meeting the dependence criteria of one or more of the following drugs: cocaine, hallucinogens, inhalants, heroin, pain relievers, sedatives, tranquilizers, or stimulants. Dependence is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). ¹ Hispanic, Asian/Pacific Islander/Native Hawaiian, American Indian/Alaska Native, and more than one race. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

SAMHSA, an agency in the Department of Health and Human Services, is the Federal Government's lead agency for improving the quality and availability of substance abuse prevention, addiction treatment, and mental health services in the United States.

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