U.S. Department of Justice 

Office of Justice Programs 

Office of Juvenile Justice and Delinquency Prevention 

J. Robert Flores, Administrator November 2008

Office of Justice Programs Innovation • Partnerships • Safer Neighborhoods	 www.ojp.usdoj.gov

Co-occurrence of Substance 

Use Behaviors in Youth 

Carl McCurley and Howard N. Snyder 

This Bulletin analyzes the prevalence and 

overlap of substance-related behaviors 

among youth, with comparisons by age 

group, gender, and race/ethnicity. It uses 

data from the first two waves of the 1997 

National Longitudinal Survey of Youth 

(NLSY97)—self-reports gathered in 1997 

and 1998 from a nationally representative 

sample of youth ages 12–17. The data are 

from questions asking about drinking alcohol during the previous 30 days, using 

marijuana during the previous 30 days, 

and ever selling or helping to sell marijuana (pot, grass), hashish (hash) or other 

hard drugs such as heroin, cocaine, or 

LSD. 

The central finding of the analysis is that, 

given one substance-related behavior, other substance-related behaviors became 

much more likely. For example, 9% of all 

youth ages 12–17 reported marijuana use 

and 8% said they had sold drugs. Among 

youth who reported drinking alcohol (23% 

of all youth ages 12–17), the level of marijuana use was 32% and the level of drug 

selling was 23%. In contrast, among youth 

ages 12–17 who did not report recent alcohol use, the level of marijuana use was 2% 

and the level of drug selling was 3%. Other 

findings include: 

◆	 Of youth who reported marijuana use, 

81% said they drank alcohol and 45% 

said they had sold drugs. 

◆	 Of youth who reported drug selling, 

68% said they drank alcohol and 54% 

reported marijuana use. In contrast, 

among youth who said they had not 

sold drugs, 19% reported drinking alcohol and 6% reported using marijuana. 

◆	 Among those who sold drugs, both 

white and Hispanic youth were more 

likely than African Americans to also 

report alcohol use; white youth who 

sold drugs were also more likely than 

African Americans who sold drugs to 

report using marijuana. 

Prevalence of substancerelated behaviors was 

tied to age 

In general, the levels of reported substance-related behaviors climbed steadily 

with increasing age. From age 12 to age 17, 

alcohol use in the previous 30 days increased more than eightfold, from 5% to 

43% of youth, as did marijuana use in the 

previous 30 days (from 2% to 17%). The 

lifetime prevalence of reported drug selling rose from 1% at age 12 to 16% at age 

17. 

A Message From OJJDP 

The issue of co-occurrence of problem 

behaviors among juveniles is of vital 

importance to all who are concerned 

with identifying and evaluating these 

behaviors, making decisions about 

placement and treatment, and delivering services. Because substancerelated behaviors such as drinking 

alcohol, using marijuana, and selling 

drugs can have such serious consequences for youth, understanding how 

these behaviors co-occur is especially 

important. 

Based on self-report data from the first 

two waves of the 1997 National 

Longitudinal Survey of Youth, this 

Bulletin answers co-occurrence questions such as "If a youth has recently 

used alcohol, what is the likelihood that 

he has also used marijuana?" or "If a 

youth has sold drugs, what are the 

chances that she also drinks alcohol 

and uses marijuana?" It also compares 

co-occurrence findings by age group, 

gender, and race/ethnicity. 

The analysis shows that a youth who 

engages in one substance-related 

behavior is much more likely to engage 

in another. For example, the percentages of youth who used marijuana or 

sold drugs were much greater among 

youth who drank alcohol than those 

who did not. These and other findings 

reported in this Bulletin contribute to 

our understanding of substance-related 

behaviors among youth and provide 

useful input for prevention and treatment efforts. 

Access OJJDP publications online at www.ojp.usdoj.gov/ojjdp 
NLSY97: a new opportunity to examine behaviors of 

U.S. youth 

Analysis of data from the 1997 National Longitudinal Survey of Youth can provide 

criminal justice practitioners and policymakers with timely insights into delinquent 

careers, overlap among law-violating behaviors, the relative impact of a variety of risk 

and protective factors on substance use, and variation across subpopulations defined 

by age, gender, race/ethnicity, labor force status, and household composition. The 

NLSY is a large, nationally representative, continuing study of adolescents who were 

ages 12 through 16 as of December 31, 1996. NLSY interviewers gather responses 

from youth to questions about a wide array of behaviors, including undesirable or 

delinquent activity. Combined, the 1997 and 1998 waves include more than 15,300 

observations of youth who were ages 12 through 17 at the time of the interview (the 

sample used in this Bulletin excludes 17-year-olds from the 1997 wave of interviews 

because they were disproportionately “young” 17-year-olds, with an average age of 17 

years and 3 months). The NLSY97 includes oversamples of both African American 

(3,951 interviews) and Hispanic (3,239 interviews) youth; weighted analysis controlled 

for this oversampling to produce nationally representative estimates of youth behavior 

overall and within age, gender, and race/ethnicity groups. The sample was also 

weighted to produce equal proportions of youth for each year of age, ignoring minor 

fluctuations by year of age (among 12- to 17-year-olds) in the size of the 1997–98 

U.S. population. 

For more information about NLSY, refer to the Compendium of National Juvenile 

Justice Data Sets on OJJDP’s Statistical Briefing Book Web site at 

http://www.ojjdp.ncjrs.gov/ojstatbb/Compendium/index.html. 

Youth ages 12–17 

Drank 

alcohol: 

23% 

Used 

marijuana: 

9% 

Sold drugs: 

8% 

◆ Among all youth ages 12–17, 23% said they drank alcohol during the previous 

30 days, 9% said they used marijuana during the previous 30 days, and 8% said 

they had ever sold drugs. 

Of youth ages 12–17, 27% reported drinking alcohol, using marijuana, 

or selling drugs 

Drank alcohol and used marijuana: 7% 

Drank alcohol and sold drugs: 5% 

Used marijuana and sold drugs: 4% 

Drank alcohol, used marijuana, 

and sold drugs: 4% 

Prevalence and 

frequency of substancerelated behaviors were 

correlated 

Among youth ages 12–14, 11% reported 

drinking alcohol, 4% reported marijuana 

use, and 3% said they had sold drugs; the 

levels for those ages 15–17 were 35%, 14%, 

and 12%, respectively.1 Just as the percentage of youth who reported substancerelated behaviors increased with age, so 

did the frequency of the reported behaviors. Youth ages 12–14 who drank alcohol 

did so on an average of 3.4 days over a 30­

day period, in contrast to 4.5 days for 

youth ages 15–17. Youth ages 12–14 who 

used marijuana did so on an average of 

6.8 days across 30 days, compared to 9.3 

days for youth ages 15–17. Youth ages 

12–14 who sold drugs did so an average of 

10.5 times in the previous year, in comparison to 16.7 times for youth ages 15–17. 

1 All references to significant differences in 

this report imply a 95% (or greater) level of 

confidence. 

About the diagrams in 

this Bulletin 

The diagrams displayed throughout 

this Bulletin depict both the prevalence 

and co-occurrence of drinking alcohol, 

using marijuana, and selling drugs. 

The total area within the white circle 

represents all youth within the indicated category, such as “Youth ages 

12–17” in the diagram on this page. 

The areas of the shaded circles within 

the white circle represent the percentage of youth within the indicated category who reported a particular behavior. For example, in the diagram on this 

page, among all youth ages 12–17, 

23% reported that they drank alcohol 

within the 30 days prior to being interviewed. The area of overlap for two circles shows the percentage of youth 

who engaged in both behaviors; the 

area of overlap for three circles shows 

the percentage of youth who engaged 

in all three behaviors. For example, in 

the diagram on this page, among 

youth ages 12–17, 4% reported all 

three behaviors. 

2 
3 

Youth ages 15–17 

Drank 

alcohol: 

35% 

Used 

marijuana: 

14% 

Sold drugs: 

12% 

Youth ages 12–14 

Drank 

alcohol: 

11% 

Used marijuana: 

4% 

Sold drugs: 

3% 

Drank alcohol and used marijuana: 3% Drank alcohol and used marijuana: 12% 

Drank alcohol and sold drugs: 2% Drank alcohol and sold drugs: 9% 

Used marijuana and sold drugs: 2% Used marijuana and sold drugs: 7% 

Drank alcohol, used marijuana, and sold drugs: 1% Drank alcohol, used marijuana, and sold drugs: 6% 

◆ Youth in the older age group (15–17) were more likely than those in the younger age group (12–14) to report drinking alcohol, 

using marijuana, or selling drugs. 

◆ Across age groups, there was substantial overlap of drinking alcohol, using marijuana, and selling drugs. 

The majority of marijuana users and drug sellers also drank alcohol, regardless of age group 

Substance-related behaviors 

were correlated with other 

problem behaviors 

NLSY97 gathered data on a number of different problem behaviors. As indicated in 

the accompanying table, substance use 

was associated with a range of other problems. Across all behaviors listed, and for 

both the younger and the older age groups, 

there were significant differences between 

the problem behavior levels reported by 

users and nonusers. For example, 31% of 

youth ages 12–14 who drank alcohol and 

18% who did not drink alcohol reported 

having been suspended from school, and 

21% of 15–17-year-olds who had used 

marijuana during the previous 30 days also 

said they had been arrested during the previous year, as opposed to 5% of those who 

had not used marijuana in the previous 30 

days. 

Higher levels of problem behaviors and delinquency appeared 

among substance users, across age groups 

Drank alcohol Used marijuana Sold drugs 

30 days 30 days ever 

Behavior No Yes No Yes No Yes 

Youth ages 12–14 

Suspended from school 18% 31% 19% 46% 19% 55% 

Vandalize property 13 37 14 50 14 56 

Major theft 2 11 2 20 2 27 

Attack/assault 8 28 9 36 9 53 

Belong to a gang 1 7 1 16 1 18 

Carry handgun 4 12 4 20 4 25 

Arrested 2 8 3 15 2 22 

Youth ages 15–17 

Suspended from school 27% 38% 27% 52% 27% 63% 

Vandalize property 10 23 11 33 11 40 

Major theft 3 10 4 17 3 23 

Attack/assault 8 21 10 29 9 37 

Belong to a gang 1 5 1 9 1 12 

Carry handgun 4 10 5 15 5 18 

Arrested 5 12 5 21 5 26 

Notes: The timeframe for “Suspended from school” was ever; for the other items, it was the 

past 12 months. The value in the “Yes” column differs significantly (p<.05) from the value in 

the “No” column for all column pairs within substance behavior and age groups. 
4 

There was significantly less overlap of drug selling, alcohol use, and marijuana use among African American 

youth than among white or Hispanic youth 

White youth 

ages 12–17 

Drank 

alcohol: 

26% 

Used 

marijuana: 

10% 

Sold 

drugs: 

8% 

Drank alcohol and used marijuana: 8% Drank alcohol and used marijuana: 5% Drank alcohol and used marijuana: 7% 

Drank alcohol and sold drugs: 6% Drank alcohol and sold drugs: 2% Drank alcohol and sold drugs: 5% 

Used marijuana and sold drugs: 5% Used marijuana and sold drugs: 2% Used marijuana and sold drugs: 4% 

Drank alcohol, used marijuana, and Drank alcohol, used marijuana, and Drank alcohol, used marijuana, and 

sold drugs: 4% sold drugs: 2% sold drugs: 4% 

◆ Both white and Hispanic youth were significantly more likely than African American youth to report any substance-related behavior 

(29%, 26%, and 19%, respectively); whites and Hispanics were both more likely than African Americans to report drinking alcohol; 

whites were more likely than African Americans to report either marijuana use or drug selling. 

Note: Racial categories do not include persons of Hispanic ethnicity. Youth of Hispanic ethnicity may be of any race. 

African American 

youth ages 12–17 

Drank 

alcohol: 

14% 

Used 

marijuana: 

7% 

Sold drugs: 

6% 

Hispanic youth 

ages 12–17 

Drank 

alcohol: 

22% 

Used 

marijuana: 

9% 

Sold drugs: 

8% 

The level of drug selling among males was higher than among females, but the levels and overlap of alcohol 

and marijuana use were similar for males and females 

Male youth 

ages 12–17 

Drank 

alcohol: 

23% 

Used 

marijuana: 

10% 

Sold drugs: 

9% 

Female youth 

ages 12–17 

Drank 

alcohol: 

23% 

Used 

marijuana: 

9% 

Sold drugs: 

6% 

Drank alcohol and used marijuana: 8% Drank alcohol and used marijuana: 7% 

Drank alcohol and sold drugs: 6% Drank alcohol and sold drugs: 4% 

Used marijuana and sold drugs: 5% Used marijuana and sold drugs: 3% 

Drank alcohol, used marijuana, and sold drugs: 4% Drank alcohol, used marijuana, and sold drugs: 3% 

◆ The patterns of substance-related behavior co-occurrence among females closely resembled those among males. 
5 

Among youth who drank alcohol, 32% also used marijuana, 23% sold drugs, and 15% did both 

Race/ethnicity 

All youth Age group Gender Non-Hispanic Non-Hispanic 

Behavior ages 12–17 12–14 15–17 Male Female White African American Hispanic 

Drank alcohol 23% 11%a 35%b 23%a 23%a 26%a 14%b 22%c 

Youth who reported 

drinking alcohol 

Drank alcohol only 60 69a 58b 58a 63a 60a 63a 60a 

Used marijuana 32 27a 34b 33a 31a 32a 34a 33a 

Sold drugs 23 17a 25b 27a 18b 24a 16a 23a 

Used marijuana and sold drugs 15 12a 16a 18a 13b 16a 12a 16a 

Youth who did not report 

drinking alcohol 

Used marijuana 2 1a 4b 3a 2b 2a 3a 2a 

Sold drugs 3 1a 6b 4a 2b 3a 4a 4a 

Used marijuana and sold drugs 1 <1a 1b 1a <1a 1a 1a 1a 

a, b, c Cell entries with different superscripts within age, gender, or race subsamples are significantly different at p<.05. For example, among youth 

who reported drinking alcohol, the proportion that only drank alcohol was not significantly different for males (58%) and females (63%), but the 

proportion that also used marijuana and sold drugs was significantly different for males (18%) and females (13%), although the difference in the 

percentages was the same in both examples. 

Note: Racial categories do not include persons of Hispanic ethnicity. Youth of Hispanic ethnicity may be of any race. 

◆ Most youth ages 12–17 who drank alcohol neither used marijuana nor sold drugs—32% used marijuana and 23% sold drugs. 

◆ However, regardless of age, gender, or race/ethnicity, youth who did not drink alcohol were much less likely than those who did 

to report marijuana use (2% vs. 32%), drug selling (3% vs. 23%), or both marijuana use and drug selling (1% vs. 15%). 

◆ Males were more likely than females to say they had ever sold drugs. This was true for males and females who drank alcohol 

(27% vs. 18%) and for males and females who did not (4% vs. 2%). 

◆ Youth ages 15–17 were more likely than youth ages 12–14 to say they used marijuana. This general pattern was found among 

youth who drank alcohol (34% vs. 27%) and among those who did not drink alcohol (4% vs. 1%). 

◆ Youth ages 15–17 were more likely than youth ages 12–14 to say they ever sold drugs. This general pattern was found among 

youth who drank alcohol (25% vs. 17%) and among youth who did not drink alcohol (6% vs. 1%). 

◆ Regardless of whether youth reported drinking alcohol, the proportion who reported marijuana use was similar across the three 

racial/ethnic groups. 

◆ Equal proportions of white, African American, and Hispanic youth who did not drink alcohol reported they sold drugs. This was 

also true among youth who drank alcohol. 

Youth who drank alcohol 

(23% of all youth ages 12–17) 

Used 

marijuana: 

32% 

Sold drugs: 

23% 

Used marijuana 

and sold drugs: 

15% 

Youth who did not 

drink alcohol 

(77% of all youth ages 12–17) 

Used marijuana: 

2% 

Sold drugs: 

3% 

Used marijuana 

and sold drugs: 

1% 
Among marijuana users, 81% also drank alcohol, 45% sold drugs, and 39% did both 

Race/ethnicity 

All youth Age group Gender Non-Hispanic Non-Hispanic 

Behavior ages 12–17 12–14 15–17 Male Female White African American Hispanic 

Used marijuana 9% 4%a 14%b 10%a 9%a 10%a 7%b 9%ab 

Youth who reported 

marijuana use 

Marijuana only 12 20a 10b 13a 12a 10a 22b 14ab 

Drank alcohol 81 74a 83b 79a 84a 84a 68b 80a 

Sold drugs 45 39a 47a 51a 38b 47a 35a 47a 

Drank alcohol and sold drugs 39 33a 40a 42a 34a 41a 25b 40a 

Youth who did not report 

marijuana use 

Drank alcohol 17 9a 27b 17a 17a 20a 10b 16c 

Sold drugs 4 2a 6b 5a 3b 4a 4a 4a 

Drank alcohol and sold drugs 2 1a 3b 2a 1a 2a 1b 2a 

a, b, c Cell entries with different superscripts within age, sex, or race subsamples are significantly different at p<.05. 

Note: Racial categories do not include persons of Hispanic ethnicity. Youth of Hispanic ethnicity may be of any race. 

◆ In general, a greater proportion of marijuana users than nonusers reported drinking alcohol and selling drugs. More specifically, 

compared with marijuana users, youth ages 12–17 who did not use marijuana were far less likely to drink alcohol (17% vs. 81%) 

or sell drugs (4% vs. 45%). This general distinction between marijuana users and nonusers held for youth regardless of age 

group, gender, or race/ethnicity. 

◆ For marijuana nonusers, older youth (ages 15–17) were more likely than younger youth (ages 12–14) to drink alcohol or sell 

drugs. Similarly, for marijuana users, a greater proportion of older youth than younger youth reported drinking alcohol (83% vs. 

74%). In contrast, the proportions of older and younger marijuana users who reported selling drugs (47% vs. 39%) were not statistically different. 

◆ For youth who reported using marijuana, similar proportions of males and females reported drinking alcohol (79% vs. 84%), 

although males were more likely to report selling drugs (51% vs. 38%). A similar pattern held for those who said they did not use 

marijuana, although their levels of drinking alcohol and selling drugs were substantially lower than those of marijuana users. 

◆ For youth who reported using marijuana, statistically equal proportions of white, African American, and Hispanic youth reported 

they had sold drugs (47%, 35%, and 47%, respectively). A similar pattern held for those who said they did not use marijuana, 

although their levels were substantially lower than those of marijuana users. 

Youth who used marijuana 

(9% of all youth ages 12–17) 

Drank alcohol: 

81% 

Sold drugs: 

45% 

Drank alcohol 

and sold drugs: 

39% 

Youth who did not 

use marijuana 

(91% of all youth ages 12–17) 

Drank alcohol: 

17% Sold drugs: 

4% 

Drank alcohol 

and sold drugs: 

2% 

6 
7 

Among youth who sold drugs, 68% drank alcohol, 54% used marijuana, and 46% did both 

Race/ethnicity 

All youth Age group Gender Non-Hispanic Non-Hispanic 

Behavior ages 12–17 12–14 15–17 Male Female White African American Hispanic 

Sold drugs 8% 3%a 12%b 9%a 6%b 8%a 6%b 8%ab 

Youth who reported they 

ever sold drugs 

Sold drugs only 24 32a 22a 25a 22a 19a 50b 28a 

Drank alcohol 68 60a 70a 66a 72a 74a 38b 65a 

Used marijuana 54 51a 55a 53a 55a 56a 41b 53ab 

Drank alcohol and used marijuana 46 43a 47a 44a 49a 49a 30b 45ab 

Youth who did not report they 

ever sold drugs 

Drank alcohol 19 10a 30b 19a 20a 22a 12b 18c 

Used marijuana 6 3a 9b 5a 6a 6a 5a 5a 

Drank alcohol and used marijuana 4 2a 7b 4a 5a 5a 3b 4ab 

a, b, c Cell entries with different superscripts within age, sex, or race subsamples are significantly different at p<.05. 

Note: Racial categories do not include persons of Hispanic ethnicity. Youth of Hispanic ethnicity may be of any race. 

◆ Among all youth ages 12–17, those who sold drugs were much more likely than those who did not sell drugs to say they drank 

alcohol (68% vs. 19%), used marijuana (54% vs. 6%), or both drank alcohol and used marijuana (46% vs. 4%). 

◆ For youth reporting they never sold drugs, greater proportions of older youth (ages 15–17) than younger youth (ages 12–14) reported they drank alcohol (30% vs. 10%) or used marijuana (9% vs. 3%). These age differences were not found among youth 

who reported they sold drugs. 

◆ Among youth who sold drugs, there were no statistically significant gender differences in the proportions that reported using alcohol (66% of males and 72% of females) or the proportions that reported using marijuana (53% of males and 55% of females). 

This lack of gender differences was also found when focusing on youth who did not sell drugs. 

◆ Drinking alcohol was reported by a greater proportion of white youth who sold drugs than African American youth who sold 

drugs (74% vs. 38%). This racial difference was also found among youth who did not sell drugs (22% vs. 12%). 

◆ Marijuana use was also reported by a greater proportion of white youth who sold drugs than African American youth who sold 

drugs (56% vs. 41%). However, this racial difference was not found among youth who did not sell drugs. 

Youth who sold drugs 

(8% of all youth ages 12–17) 

Drank 

alcohol: 

68% 

Used 

marijuana: 

54% 

Drank alcohol and 

used marijuana: 

46% 

Youth who did not 

sell drugs 

(92% of all youth ages 12–17) 

Drank alcohol: 

19% Used marijuana: 

6% 

Drank alcohol and 

used marijuana: 

4% 
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Bulletin Bulletin NCJ 219239

How do NLSY97 results compare to other drug use 

survey results? 

Prevalence estimates for substance use produced from NLSY97 data tend to fall 

between those derived from the two major, federally funded drug use surveys—the 

National Survey on Drug Use and Health (NSDUH, formerly the National Household 

Survey on Drug Abuse) and Monitoring the Future (MTF). NLSY97 estimates (for 

1997 and 1998) match the 1998 NSDUH estimate of the percentage of youth ages 

12–17 who used marijuana during the 30 days before the interview (30-day prevalence): 9% for NSDUH and 9% for NLSY97. Reported levels of drinking alcohol were 

also similar: the NSDUH 1998 estimate of 30-day alcohol prevalence was 21%, 

whereas the NLSY97 estimate was 23%. In contrast, MTF prevalence estimates are 

higher than those from the NLSY97 (or from the NSDUH). For example, the 1997 30­

day marijuana prevalence estimate for 10th graders from MTF was 20%, compared 

with 13% for NLSY97; for 30-day alcohol prevalence, the MTF 10th grader estimate 

was 40% and the NLSY97 estimate was 32%. 

Acknowledgments 

This Bulletin was written by Carl McCurley, former Research Associate, and Howard 

N. Snyder, former Director of Systems Research, at the National Center for Juvenile 

Justice, with funds provided by OJJDP to support the National Juvenile Justice Data 

Analysis Project. 

This Bulletin was prepared under cooperative 

agreement number 1999–JN–FX–K002 from the 

Office of Juvenile Justice and Delinquency 

Prevention (OJJDP), U.S. Department of Justice. 

Points of view or opinions expressed in this document are those of the authors and do not necessarily represent the official position or policies 

of OJJDP or the U.S. Department of Justice. 

The Office of Juvenile Justice and Delinquency 

Prevention is a component of the Office of 

Justice Programs, which also includes the Bureau of Justice Assistance; the Bureau of Justice 

Statistics; the Community Capacity Development 

Office; the National Institute of Justice; the Office 

for Victims of Crime; and the Office of Sex 

Offender Sentencing, Monitoring, Apprehending, 

Registering, and Tracking (SMART).