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Risk and Protective Factors for Adolescent Drug Use:
Findings from the 1999 National Household Survey on Drug Abuse

Chapter 3. Associations Between Risk and Protective Factors and Past Year Marijuana Use

3.1 Introduction

This chapter presents the associations between the reported levels of risk and protective factors and past year marijuana use among youths in the 1999 National Household Survey on Drug Abuse (NHSDA). This chapter addresses the following issues:

In general, higher levels of all risk factors were significantly associated with a higher likelihood of past year marijuana use, and higher levels of all protective factors (with the exception of parental communication about the dangers of substance use) were significantly associated with a lower likelihood of past year marijuana use.

These associations are first presented in bar charts showing the percentages of youths who reported past year marijuana use by categories of each risk or protective factor. The categories given are quartiles for factors derived from multiple items. The first quartile represents the lowest 25 percent of scores on the scale, and the fourth quartile represents the highest 25 percent of scores on the scale. The categories given for factors derived from single items are the response options on the relevant question. In some cases, the response options for single items have been combined for clarity of presentation.

For example, in this chapter's first figure, only 10.5 percent of youths who believed that adults in their community would strongly disapprove of marijuana use actually used marijuana in the past year, while 27.8 percent of youths who felt that adults would neither approve nor disapprove, or only somewhat disapprove, reported using it in the past year. In the language of probability, this indicates that the odds of not using marijuana in the past year for the strongly disapprove group were 89.5 / 10.5, or about 8.5 to 1. For the neither/somewhat disapprove group, the odds of not using marijuana in the past year were 72.2 / 27.8, or about 2.6 to 1. The ratio of these two odds (i.e., the "odds ratio" [OR]) comparing the strongly disapprove group tothe neither/somewhat disapprove group is (89.5 / 10.5) / (72.2 / 27.8), or about 3.3 to 1, indicating that youths who reported that adults in their community would strongly disapprove of occasional marijuana use were about 3 times more likely not to have used marijuana in the past year than other youths. Unless otherwise indicated, all statements indicating an association between a risk or protective factor and past year use of marijuana have been tested and are statistically significant at the .05 level.

Although the chapter provides evidence of statistical associations between risk and protective factors and past year marijuana use, the associations in cross-sectional data such as these do not carry with them the inference of causality (e.g., that the presence of a risk factor is the reason that youths use marijuana). Inferences of causality ideally require rigorous experiments in which a representative sample of youths are randomly assigned to either a "treatment group" (e.g., youths who are put in a situation that could decrease their use of marijuana use) or a "control group" (e.g., a comparison group of youths who are not put in such a situation). If these two groups are measured both before and after the "treatment," and if statistically significant differences in the behavior of interest are found between these groups, it can be inferred that the treatment was the reason for the difference. In prevention research, where the introduction of a risk factor to a random group of subjects is typically not permitted, causality related to risk factors is best determined through longitudinal designs in which a cohort or panel is followed over time (Bauman, 1980). This type of design enables the researchers to identify the temporality of the relationships between risk factors and behaviors, which is highly desirable for inferring which was the cause and which was the effect. Although the analyses in this report do not establish causality, it is likely that the cross-sectional associations of this chapter reflect a certain degree of bidirectional causality. For example, easy availability of marijuana may have led to marijuana use, or marijuana use may have led to easy availability of the substance, or both. Therefore, even though tests of these associations typically indicate statistically significant relations between risk and protective factors and past year marijuana use, they do not show that the propensity to use marijuana is a direct result of the presence of risk and protective factors.

Table 3.1 presents the prevalence rates among youths aged 12 to 17 for past year use of marijuana for the Nation as a whole and for selected demographic categories. For comparison purposes, Table 3.1 also includes rates of past year cigarette use and alcohol use among youths. Significance tests of the simple associations between marijuana use and risk and protective factors are presented in tables utilizing ORs as described above. ORs provide a convenient way to describe how varying levels of risk and protective factors are associated with the increased (or decreased) probability of a behavior that is measured using a "yes" or "no" indicator. The first set of ORs that is presented does not adjust for differences in demographic characteristics, such as age, race/ethnicity, and gender, that are typically associated with marijuana use (Tables 3.2 to 3.5). ORs are then presented for demographic characteristics (Table 3.6). Subsequently, ORs arepresented separately for different racial/ethnic groups (whites, blacks, Hispanics, and "others"), as well as by gender (Tables 3.7 to 3.10). Finally, ORs are presented after statistically adjusting for a set of demographic variables (Tables 3.11 to 3.14).

3.2 Prevalence of Past Year Marijuana Use

As a context for the discussion of the association between risk and protective factors and marijuana use, in 1999 approximately 14.2 percent of youths reported using marijuana in the past year (Table 3.1).

3.3 Community Domain

3.3.1 Community Domain Risk Factors

Figure 3.1 shows the percentages of youths who reported using marijuana in the past year by risk factor categories within the community domain. Youths with scores in the highest quartile of the community disorganization and crime scale (reported the most disorganization and crime) were more likely to have used marijuana in the past year (18.9 percent) compared with youths in the lowest quartile (11.7 percent). Youths who reported that adults in their neighborhood would somewhat disapprove or neither approve nor disapprove if they were to try marijuana once or twice were more likely to have used marijuana in the past year (27.8 percent) compared with youths who responded that adults in their neighborhood would strongly disapprove (10.5 percent). Youths who reported that most or all of the adults they personally knew used marijuana were more likely to have used marijuana in the past year (46.3 percent) compared with youths who knew few adult marijuana users (32.7 percent) or no adult marijuana users (6.0 percent). Finally, youths who reported that marijuana would be fairly easy or very easy to obtain were more likely to have used marijuana in the past year (29.6 percent) compared with youths who reported that marijuana would be difficult or impossible to obtain (23.5 percent).

Figure 3.1 Percentages of Youths Aged 12 to 17 Reporting Past Year Marijuana Use, by Community Domain Risk Factors: 1999

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Note: The questions used to measure each of the factors are provided in Appendix A (Table A.1). The coding and distribution of the responses for each factor are provided in Table 2.1.

1 Higher responses for risk factors generally indicate a higher risk of substance use. Quartile 4 consists of the highest 25 percent of youth scores, ranging between 2.01 and 4.00, which represent the highest level of community disorganization and crime.

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

3.3.2 Community Domain Protective Factors

Figure 3.2 shows the percentages of youths who reported using marijuana in the past year by protective factor categories within the community domain. Youths with scores in the fourth quartile of the neighborhood cohesion scale (reported the most neighborhood cohesion) were less likely to have used marijuana in the past year (11.8 percent) compared with youths in the first quartile (16.9 percent). Youths who had been exposed to prevention messages in the media were less likely to have used marijuana in the past year (13.3 percent) compared with youths who had not been exposed to these types of messages (17.9 percent).

Figure 3.2 Percentages of Youths Aged 12 to 17 Reporting Past Year Marijuana Use, by Community Domain Protective Factors: 1999

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Note: The questions used to measure each of the factors are provided in Appendix A (Table A.1). The coding and distribution of the responses for each factor are provided in Table 2.1.

1 Higher responses for protective factors generally indicate a higher level of protection and reduced risk of substance use. Quartile 4 consists of the highest 25 percent of youth scores, ranging between 3.51 and 4.00, which represent the highest level of neighborhood cohesion.

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

3.4 Family Domain

3.4.1 Family Domain Risk Factors

Figure 3.3 shows the percentages of youths who reported using marijuana in the past year by risk factor categories within the family domain. Youths with scores in the fourth quartile for parental monitoring (reported the least parental monitoring) were more likely to have used marijuana in the past year (28.4 percent) compared with youths who reported more parental monitoring. Youths were also more likely to have used marijuana in the past year if they believed their parents would only somewhat disapprove or neither approve nor disapprove if they used marijuana (41.7 percent) compared with youths who believed their parents would strongly disapprove of their marijuana use (11.3 percent).

Figure 3.3 Percentages of Youths Aged 12 to 17 Reporting Past Year Marijuana Use, by Family Domain Risk Factors: 1999

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Note: The questions used to measure each of the factors are provided in Appendix A (Table A.2). The coding and distribution of the responses for each factor are provided in Table 2.2.

1 Higher responses for risk factors generally indicate a higher risk of substance use. Quartile 4 consists of the highest 25 percent of youth scores, ranging between 2.41 and 4.00, which represent the lowest level of parental monitoring.

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

3.4.2 Family Domain Protective Factors

Figure 3.4 shows the percentages of youths who reported using marijuana in the past year by protective factor categories within the family domain. Youths with scores in the highest quartiles on the parental encouragement scale (reported the most encouragement) were less likely to have used marijuana in the past year (9.6 percent) compared with youths with scores in the lowest quartile (19.7 percent). Youths who selected one of their parents as the person they would talk with if they had a serious problem were less likely to have smoked marijuana in the past year (10.6 percent) compared with youths who selected someone other than their parents (22.9 percent). The association between parental communication about substance use and past year marijuana use was not statistically significant. The failure to find a significant relationship here is somewhat counterintuitive in that one would expect that the initiation by parents of a discussion of the dangers of substance use with their child would lead to a lower probability of that youth using illicit substances. One explanation might be that the cross-sectional nature of the NHSDA captured a significant number of cases in which the parental discussion came after having evidence or a strong suspicion that the child had used or was using an illicit substance.

Figure 3.4 Percentages of Youths Aged 12 to 17 Reporting Past Year Marijuana Use, by Family Domain Protective Factors: 1999

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Note: The questions used to measure each of the factors are provided in Appendix A (Table A.2). The coding and distribution of the responses for each factor are provided in Table 2.2.

1 Higher responses for protective factors generally indicate a higher level of protection and reduced risk of substance use. Quartiles 3 and 4 consist of the highest 50 percent of youth scores, ranging between 3.51 and 4.00, which represent the highest level of parental encouragement.

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

3.5 Peer/Individual Domain

3.5.1 Peer/Individual Domain Risk Factors

Figure 3.5 shows the percentages of youths who reported using marijuana in the past year by risk factor categories within the peer/individual domain. For each of these factors, youths with higher levels of the factor were more likely to have used marijuana in the past year compared with youths with lower levels of the factor. The associations with past year marijuana use were strongest for individual positive attitudes toward marijuana use, friends' positive attitudes toward marijuana use, and friends' use of marijuana. Youths who reported that they would somewhat disapprove or neither approve nor disapprove of marijuana use by someone their age were more likely to have used marijuana in the past year (32.2 percent) compared with youths who reported that they would strongly disapprove of youth marijuana use (3.6 percent). Similarly, youths who reported that their friends would somewhat disapprove or neither approve nor disapprove of the youth using marijuana were more likely to have used marijuana in the past year (32.4 percent) compared with youths that reported that their friends would strongly disapprove of the youth using marijuana (3.5 percent). Finally, youths who reported that most or all of their friends used marijuana were more likely to have used marijuana in the past year (59.4 percent) compared with youths who reported that few or none of their friends used marijuana (20.0 and 2.1 percent, respectively).

Figure 3.5 Percentages of Youths Aged 12 to 17 Reporting Past Year Marijuana Use, by Peer/Individual Domain Risk Factors: 1999

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Note: The questions used to measure each of the factors are provided in Appendix A (Table A.3). The coding and distribution of the responses for each factor are provided in Table 2.3.

1 Higher responses for risk factors generally indicate a higher risk of substance use. Quartile 4 consists of the highest 25 percent of youth scores for a given factor, which represents the highest level of risk. For example, Quartile 4 for antisocial behavior consists of the highest 25 percent of youth scores, ranging between 1.18 and 5.00, and represents the highest level of antisocial behavior.

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

3.5.2 Peer/Individual Domain Protective Factors

Figure 3.6 shows the percentages of youths who reported using marijuana in the past year by protective factor categories within the peer/individual domain. Youths who had participated in two or more extracurricular activities in the past year were less likely to have used marijuana in the past year (11.5 percent) compared with youths who had not (20.0 percent). Youths in the lowest quartile of the religiosity scale (reported the lowest level of religiosity) were more than 4 times more likely to have used marijuana in the past year (23.3 percent) compared with youths in the highest quartile (5.0 percent).

Figure 3.6 Percentages of Youths Aged 12 to 17 Reporting Past Year Marijuana Use, by Peer/Individual Domain Protective Factors: 1999

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Note: The questions used to measure each of the factors are provided in Appendix A (Table A.3). The coding and distribution of the responses for each factor are provided in Table 2.3.

1 Higher responses for protective factors generally indicate a higher level of protection and reduced risk of substance use. Quartile 4 consists of the highest 25 percent of youth scores, ranging between 3.26 and 4.00, which represent the highest level of religiosity.

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

3.6 School Domain

3.6.1 School Domain Risk Factors

Figure 3.7 shows the percentages of youths who reported using marijuana in the past year by risk factor categories within the school domain.16 Youths who reported that most or all of the students in their grade at school used marijuana were more likely to be past year marijuana users (41.4 percent) compared with youths who reported that few or none of the students in their grade at school used marijuana (11.8 and 1.6 percent, respectively). Youths were also more likely to have used marijuana in the past year if they reported poor academic performance in their last completed semester.

Figure 3.7 Percentages of Youths Aged 12 to 17 Reporting Past Year Marijuana Use, by School Domain Risk Factors: 1999

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Note: The questions used to measure each of the factors are provided in Appendix A (Table A.4). The coding and distribution of the responses for each factor are provided in Table 2.4.

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

3.6.2 School Domain Protective Factors

Figure 3.8 shows the percentages of youths who reported using marijuana in the past year by protective factor categories within the school domain. Youths with scores in the highest quartile of the commitment to school scale were less likely to have used marijuana in the past year (9.1 percent) compared with youths in the lowest quartile (24.0 percent). Youths who reported that a student in their grade at school would be in a lot of trouble if they used marijuana were less likely to have used marijuana in the past year (14.3 percent) compared with those who reported that a student would be in no trouble at all or a little trouble (22.6 percent). Finally, youths who had been exposed to substance abuse prevention messages during school were less likely to have used marijuana in the past year (13.9 percent) compared with those who had not (20.4 percent).

Figure 3.8 Percentages of Youths Aged 12 to 17 Reporting Past Year Marijuana Use, by School Domain Protective Factors: 1999

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Note: The questions used to measure each of the factors are provided in Appendix A (Table A.4). The coding and distribution of the responses for each factor are provided in Table 2.4.

1 Higher responses for protective factors generally indicate a higher level of protection and reduced risk of substance use. Quartile 4 consists of the highest 25 percent of youth scores, ranging between 3.51 and 4.00, which represent the highest level of commitment to school.

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

3.7 Significance Tests for Associations with Past Year Marijuana Use

The discussion to this point has focused on the associations between the risk and protective factors and past year marijuana use, as represented in the figures. The tests of those associations are presented by domain in Tables 3.2 through 3.5, with the associations represented as odds ratios (ORs) as described earlier. ORs greater than one indicate that a higher level of the factor is associated with a higher likelihood of past year marijuana use, whereas ORs less than one indicate that a higher level of the factor is associated with a lower likelihood of past year marijuana use.

All of the risk and protective factors were significantly associated with past year marijuana use, with the exception of parental communication about the dangers of substance use. The risk factors in all domains had ORs greater than one, indicating that higher levels of these risk factors were associated with a higher likelihood of past year marijuana use. The protective factors in all domains had ORs less than one, indicating that higher levels of these factors were associated with a lower likelihood of past year marijuana use.

3.8 Demographic Variables

Table 3.6 shows the odds of past year marijuana use by age, gender, race/ethnicity, number of parents in the home, household income, county type, and geographic region. Most of these variables displayed significant differences between one or more levels in the odds of past year marijuana use, which confirms the differences that were apparent in Table 3.1.

Youths aged 15 to 17 had a higher odds of past year use of marijuana than youths aged 12 to 14. Males showed a slightly higher odds of past year use than females. Blacks were less likely than whites to have used marijuana in the past year. Youths in two-parent families had lower odds of past year marijuana use than other youths. Youths in large and small metropolitan statistical areas (MSAs) had somewhat higher odds of marijuana use in the past year than youths from non-MSAs. Youths in the West region had higher odds of having used marijuana in the past year than youths in the other regions.

3.9 Associations of Factors with Marijuana Use, by Race/Ethnicity and Gender

Having examined and confirmed the associations between risk and protective factors and marijuana use, one might ask if these associations would be the same among various demographic subgroups. Tables 3.7 through 3.10 provide the ORs for different race/ethnicity and gender categories with each risk and protective factor domain presented in a separate table.  Statistically significant associations were found between most, but not all, factors and past year use of marijuana for each racial/ethnic group and gender. The strength of the relationships, however, was not necessarily the same in all groups.

Within the community domain, higher levels of neighborhood cohesiveness were significantly associated with lower odds of past year marijuana use for whites (OR = 0.72) and blacks (OR = 0.81), but not for Hispanics or youths in the "other" category (Table 3.7). Exposure to prevention messages in the media was significantly associated with lower odds of past year marijuana use for whites (OR = 0.68) and Hispanics (OR = 0.63), but not for blacks or youths in the "other" category.

Within the family domain, higher levels of parental communication about substances were significantly associated with lower odds of past year marijuana use among Hispanic youths (OR = 0.67), but not among youths of other racial/ethnic groups (Table 3.8). Within the peer/individual domain, participation in two or more extracurricular activities was significantly associated with lower odds of past year marijuana use among whites (OR = 0.45), blacks (OR = 0.64), and Hispanics (OR = 0.70), but not for youths in the "other" category (Table 3.9). Within the school domain, strong sanctions against illegal drug use were significantly associated with lower odds of past year marijuana use among whites (OR = 0.48), Hispanics (OR = 0.61), and youths in the "other" category (OR = 0.31), but not for blacks (Table 3.10). Finally, exposure to prevention messages in school was associated with lower odds of past year marijuana use for whites (OR = 0.60) and Hispanics (OR = 0.55), but not for blacks or youths in the "other" category.

The associations between the risk and protective factors and past year marijuana use were consistent between males and females for all factors. Significant associations were found for both males and females on all factors, with the exception of parental communication with youths about the dangers of substance use, which was not significant for either gender.

3.10 Associations of Factors with Marijuana Use, Adjusting for Demographic Variables

Given the significant differences discussed above between demographic groups in past year marijuana use and risk and protective factors, one could ask whether the associations between risk and protective factors and past year marijuana use presented in Tables 3.2 through 3.5 and 3.7 through 3.10 would still be found after adjusting for all of these demographic characteristics simultaneously. The ORs between each risk and protective factor and past year marijuana use after adjusting for demographic differences are presented in Tables 3.11 to 3.14, with each domain of factors presented in a separate table.

The tables show that, with the exception of parental communication with youths about the dangers of substance abuse, the ORs between the risk and protective factors and past year marijuana use were still significant after adjusting for the demographic differences. Therefore, risk and protective factors display the expected association with marijuana use, irrespective of gender, race/ethnicity, household income, number of parents in the household, county type, or geographic region.

Table 3.1 Sample Size, Estimated Population Size, and Percentages Reporting Past Year Marijuana Use, Cigarette Use, and Alcohol Use among Youths Aged 12 to 17, by Demographics: 1999

Demographic Characteristic Sample
Size1
Estimated
Population
Size2
Marijuana Use Cigarette Use Alcohol Use
Percent Standard
Error
Percent Standard
Error
Percent Standard
Error
Overall 25,357 23,203,000 14.2 0.29 23.4 0.37 34.1 0.41
Age in Years                
     12 3,967 3,570,000 1.5 0.24 5.1 0.43 7.4 0.52
     13 4,385 4,017,000 4.7 0.41 13.4 0.61 17.8 0.73
     14 4,416 4,068,000 10.1 0.55 20.5 0.75 30.0 0.93
     15 4,192 3,797,000 17.1 0.73 27.6 0.86 41.2 0.98
     16 4,333 4,032,000 24.1 0.80 33.6 0.91 49.9 0.94
     17 4,064 3,719,000 27.1 0.87 39.5 0.97 57.8 0.93
Gender                
     Male 12,798 11,877,000 14.9 0.41 23.4 0.50 33.6 0.54
     Female 12,559 11,326,000 13.3 0.39 23.4 0.51 34.7 0.58
Race/Ethnicity                
     White (non-Hispanic) 17,125 15,485,000 14.6 0.34 26.0 0.45 36.7 0.47
     Black (non-Hispanic) 3,384 3,306,000 12.1 0.78 15.8 0.85 23.7 1.01
     Hispanic 3,516 3,219,000 14.9 0.83 20.6 0.93 35.2 1.10
     Other3 1,332 1,193,000 11.6 1.47 18.3 1.58 27.2 2.08
Number of Parents in Home                
     Two 17,620 16,407,000 12.0 0.32 21.2 0.43 32.5 0.48
     Less than two 7,737 6,796,000 19.4 0.59 28.8 0.66 38.2 0.73
Household Income                
     greater than or equal to$20,000 20,457 18,832,000 14.2 0.32 23.5 0.41 34.8 0.45
     <$20,000 4,900 4,371,000 14.2 0.67 23.1 0.80 31.3 0.93
County Type4                
     Large metro 10,116 11,558,000 14.4 0.44 21.0 0.54 33.2 0.65
     Small metro 8,316 6,992,000 14.7 0.52 25.1 0.67 34.6 0.72
     Nonmetro 6,925 4,652,000 12.8 0.48 26.7 0.74 35.9 0.76
Geographic Region                
     Northeast 4,475 4,154,000 14.0 0.75 22.9 0.96 36.1 1.16
     Midwest 6,530 5,471,000 14.3 0.56 26.0 0.77 35.5 0.73
     South 7,731 8,245,000 12.9 0.46 24.3 0.63 32.0 0.67
     West 6,621 5,333,000 16.0 0.60 19.8 0.61 34.5 0.88
1 The number of youths aged 12 to 17 who completed the 1999 NHSDA.
2 The estimated number of youths aged 12 to 17 in the United States.
3 "Other" includes those other than whites, blacks, and Hispanics (i.e., Asians, American Indians or Alaska Natives, or Native Hawaiians or other Pacific Islanders).
4 Large metro = metropolitan statistical areas (MSAs) with population of 1 million or more; small metro = MSAs with population of 50K to < 1 million; nonmetro = not part of an MSA.

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

Table 3.2 Odds Ratios and Confidence Intervals (95 Percent) of Community Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

Community Domain1 Odds of Past Year Marijuana Use
Risk/Protective Factor Unadjusted OR2 p value 95% CI
Community Disorganization and Crime Risk 1.43 <.0001 (1.33, 1.54)
Neighborhood Cohesiveness Protective 0.79 <.0001 (0.74, 0.84)
Community Attitudes Toward Substance Use Risk      
     Multiple substance scale3   2.23 <.0001 (2.10, 2.38)
     Marijuana (try once or twice)   1.95 <.0001 (1.84, 2.07)
Community Norms Toward Substance Use Risk      
     Multiple substance scale3   5.09 <.0001 (4.62, 5.61)
     Marijuana (try once or twice)   4.14 <.0001 (3.78, 4.53)
Availability of Marijuana Risk 2.72 <.0001 (2.55, 2.90)
Exposed to Prevention Messages in Media Protective 0.70 <.0001 (0.63, 0.79)
CI = confidence interval.

1 The questions used to measure each of the factors are provided in Appendix A (Table A.1). The coding and distribution of the responses for each factor are provided in Table 2.1.
2 Odds ratios (ORs) are based on separate logistic regression models of past year marijuana use for each of the factors. ORs have not been adjusted for demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. ORs < 1.0 indicate that the odds of past year marijuana use decreased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use. An OR of 1.43 for the community disorganization and crime risk factor indicates that the odds of past year marijuana use increased 1.43 times with each unit increase in the community disorganization and crime scale.
3 Multiple substance scales take the mean of responses for marijuana, cigarettes, and alcohol.

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

Table 3.3 Odds Ratios and Confidence Intervals (95 Percent) of Family Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

Family Domain1 Odds of Past Year Marijuana Use
Risk/Protective Factor Unadjusted OR2 p value 95% CI
Parental Monitoring Risk 2.60 <.0001 (2.40, 2.82)
Parental Encouragement Protective 0.59 <.0001 (0.56, 0.62)
Parental Attitudes Toward Substance Use Risk      
     Multiple substance scale3   2.84 <.0001 (2.59, 3.12)
     Marijuana (try once or twice)   2.47 <.0001 (2.28, 2.67)
Parents Communicate About Substance Use Protective 0.97  .4747 (0.88, 1.06)
Parents Are Source of Social Support Protective 0.40 <.0001 (0.37, 0.44)
CI = confidence interval.

1 The questions used to measure each of the factors are provided in Appendix A (Table A.2). The coding and distribution of the responses for each factor are provided in Table 2.2.
2 Odds ratios (ORs) are based on separate logistic regression models of past year marijuana use for each of the factors. ORs have not been adjusted for demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. ORs < 1.0 indicate that the odds of past year marijuana use decreased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use. An OR of 2.60 for the parental monitoring risk factor indicates that the odds of past year marijuana use increased 2.60 times with each unit increase in the parental monitoring scale (note that high scores on the parental monitoring scale indicate low levels of monitoring).
3 Multiple substance scales take the mean of responses for marijuana, cigarettes, and alcohol.

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

Table 3.4 Odds Ratios and Confidence Intervals (95 Percent) of Peer/Individual Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

Peer/Individual Domain1 Odds of Past Year Marijuana Use
Risk/Protective Factor Unadjusted OR2 p value 95% CI
Antisocial Behavior Risk 7.10 <.0001 (6.02, 8.38)
Individual Attitudes Toward Substance Use Risk      
     Multiple substance use        
     Marijuana (try once or twice)   4.47 <.0001 (4.19, 4.75)
Friends' Attitudes Toward Substance Use Risk      
     Multiple substance scale3   4.19 <.0001 (3.94, 4.47)
     Marijuana (try once or twice)   4.37 <.0001 (4.12, 4.64)
Friends' Substance Use Risk      
     Multiple substance scale3   8.05 <.0001 (7.41, 8.74)
     Marijuana   6.25 <.0001 (5.80, 6.74)
Perceived Risk of Substance Use Risk      
     Multiple substance scale3   3.76 <.0001 (3.49, 4.05)
     Marijuana   3.48 <.0001 (3.29, 3.68)
Risk-Taking Proclivity Risk 3.27 <.0001 (3.05, 3.50)
Participated in Two or More Extracurricular Activities Protective 0.52 <.0001 (0.47, 0.57)
Religiosity Protective 0.47 <.0001 (0.44, 0.50)
CI = confidence interval.

1 The questions used to measure each of the factors are provided in Appendix A (Table A.3). The coding and distribution of the responses for each factor are provided in Table 2.3.
2 Odds ratios (ORs) are based on separate logistic regression models of past year marijuana use for each of the factors. ORs have not been adjusted for demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. ORs < 1.0 indicate that the odds of past year marijuana use decreased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use. An OR of 7.10 for the antisocial behavior risk factor indicates that the odds of past year marijuana use increased 7.10 times with each unit increase in the antisocial behavior scale.
3 Multiple substance scales take the mean of responses for marijuana, cigarettes, and alcohol.

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

Table 3.5 Odds Ratios and Confidence Intervals (95 Percent) of School Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

School Domain1 Odds of Past Year Marijuana Use
Risk/Protective Factor Unadjusted OR2 p value 95% CI
Commitment to School Protective 0.45 <.0001 (0.42, 0.48)
Sanctions Against Substance Use at School Protective      
     Multiple substance scale3   0.28 <.0001 (0.25, 0.32)
     Marijuana   0.52 <.0001 (0.45, 0.59)
Perceived Prevalence of Substance Use Risk      
     Multiple substance scale3   6.05 <.0001 (5.49, 6.68)
     Marijuana   4.78 <.0001 (4.40, 5.19)
Academic Performance Risk 1.81 <.0001 (1.70, 1.92)
Exposed to Prevention Messages in School Protective 0.63

<.0001

(0.56, 0.70)
CI = confidence interval.

1 The questions used to measure each of the factors are provided in Appendix A (Table A.4). The coding and distribution of the responses for each factor are provided in Table 2.4.
2 Odds ratios (ORs) are based on separate logistic regression models of past year marijuana use for each of the factors. ORs have not been adjusted for demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. ORs < 1.0 indicate that the odds of past year marijuana use decreased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use. An OR of 4.78 for the perceived prevalence of marijuana risk factor indicates that the odds of past year marijuana use increased 4.78 times with each unit increase in the perceived prevalence of marijuana question.
3 Multiple substance scales take the mean of responses for marijuana, cigarettes, and alcohol.

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

Table 3.6 Odds Ratios and Confidence Intervals (95 Percent) of Demographics and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

Demographic Characteristic Odds of Past Year Marijuana Use
Unadjusted OR1 p value 95% CI
Age (Continuous - 12 to 17) 1.67 <.0001 (1.63, 1.72)
Gender (Male vs. Female) 1.14 .0047 (1.04, 1.25)
Race/Ethnicity      
     Black vs. white 0.81 .0064 (0.69, 0.94)
     Hispanic vs. white 1.02 .7473 (0.89, 1.18)
     Other2 vs. white 0.77 .0731 (0.57, 1.03)
Number of Parents in Home (2 vs. Others) 0.57 <.0001 (0.52, 0.62)
Economic Deprivation (Household Income <$20,000) 1.00 1.0000 (0.89, 1.13)
County Type      
     Large MSA vs. non-MSA 1.15 .0166 (1.03, 1.28)
     Small MSA vs. non-MSA 1.18 .0059 (1.05, 1.33)
Geographic Region      
     Northeast vs. West 0.85 .0375 (0.73, 0.99)
     Midwest vs. West 0.87 .0299 (0.77, 0.99)
     South vs. West 0.78 <.0001 (0.69, 0.88)
CI = confidence interval; MSA = metropolitan statistical area.

1 Odds ratios (ORs) are based on separate logistic regression models of past year marijuana use for each of the demographic variables. ORs have not been adjusted for other demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. ORs < 1.0 indicate that the odds of past year marijuana use decreased with each unit increase in the predictor. An OR of 1.67 for age indicates that the odds of past year marijuana use increased 1.67 times with each unit increase in age.
2 "Other" includes those other than whites, blacks, Hispanics (i.e., Asians, American Indians or Alaska Natives, or Pacific Islanders).

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

Table 3.7 Unadjusted Odds Ratios and Confidence Intervals (95 Percent) of Community Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17, by Race/Ethnicity and Gender: 1999

Community Domain2 Race/Ethnicity Gender
Whites Blacks Hispanics Other1 Males Females
OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value
Community Disorganization and Crime 1.54
(1.40, 1.69)
<.0001 1.28
(1.08, 1.53)
.0055 1.43
(1.20, 1.69)
.0001 2.82
(1.94, 4.10)
<.0001 1.48
(1.35, 1.63)
<.0001 1.36
(1.23, 1.51)
<.0001
Neighborhood Cohesiveness 0.72
(0.67, 0.77)
<.0001 0.81
(0.69, 0.95)
.0095 1.00
(0.85, 1.18)
.9888 0.88
(0.65, 1.20)
.4226 0.79
(0.73, 0.86)
<.0001 0.79
(0.72, 0.85)
<.0001
Community Attitudes Toward Substance Use                        
     Multiple substance scale4 2.65
(2.45, 2.88)
<.0001 1.67
(1.42, 1.98)
<.0001 1.72
(1.48, 2.01)
<.0001 2.55
(1.84, 3.52)
<.0001 2.43
(2.22, 2.65)
<.0001 2.03
(1.86, 2.22)
<.0001
     Marijuana (trying once or
     twice)
2.31
(2.14, 2.49)
<.0001 1.57
(1.35, 1.83)
<.0001 1.49
(1.30, 1.70)
<.0001 2.11
(1.53, 2.91)
<.0001 2.12
(1.96, 2.30)
<.0001 1.76
(1.62, 1.92)
<.0001
Community Norms Toward Substance Use                        
     Multiple substance scale4 6.29
(5.58, 7.11)
<.0001 3.22
(2.61, 3.97)
<.0001 4.02
(3.12, 5.19)
<.0001 7.38
(4.37, 12.47)
<.0001 5.13
(4.49, 5.88)
<.0001 5.07
(4.37, 5.89)
<.0001
     Marijuana (trying once or
     twice)
5.60
(4.97, 6.30)
<.0001 2.57
(2.19, 3.01)
<.0001 3.28
(2.64, 4.07)
<.0001 4.36
(2.34, 8.15)
<.0001 4.15
(3.67, 4.70)
<.0001 4.13
(3.61, 4.73)
<.0001
Availability of Marijuana 3.20
(2.95, 3.48)
<.0001 2.12
(1.84, 2.44)
<.0001 2.04
(1.75, 2.38)
<.0001 2.62
(2.01, 3.42)
<.0001 2.45
(2.26, 2.67)
<.0001 3.15
(2.86, 3.47)
<.0001
Exposed to Prevention Messages (Yes vs. No) 0.68
(0.59, 0.78)
<.0001 0.86
(0.62, 1.19)
.3738 0.63
(0.48, 0.83)
.0010 0.72
(0.40, 1.33)
.2966 0.64
(0.55, 0.74)
<.0001 0.82
(0.69, 0.97)
.0208
OR = odds ratio; CI = confidence interval.

1 "Other" includes those other than whites, blacks, and Hispanics (i.e., Asians, American Indians or Alaska Natives, or Native Hawaiians or other Pacific Islanders).
2 The questions used to measure each of the factors are provided in Appendix A (Table A.1). The coding and distribution of the responses for each factor are provided in Table 2.1.
3 ORs are based on separate logistic regression models of past year marijuana use for each of the factors, run separately for each of the categories of race/ethnicity and gender. ORs have not been adjusted for demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use.
4 Multiple substance scales take the mean of responses for marijuana, cigarette, and alcohol use.

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

Table 3.8 Unadjusted Odds Ratios and Confidence Intervals (95 Percent) of Family Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17, by Race/Ethnicity and Gender: 1999

Family Domain2 Race/Ethnicity Gender
Whites Blacks Hispanics Other1 Males Females
OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value
Parental Monitoring 2.72
(2.48, 2.99)
<.0001 2.25
(1.82, 2.79)
<.0001 2.46
(1.95, 3.12)
<.0001 2.09
(1.35, 3.24)
.0010 2.49
(2.21, 2.80)
<.0001 2.73
(2.44, 3.05)
<.0001
Parental Encouragement 0.56
(0.53, 0.60)
<.0001 0.67
(0.58, 0.78)
<.0001 0.61
(0.53, 0.71)
<.0001 0.55
(0.41, 0.72)
<.0001 0.60
(0.56, 0.65)
<.0001 0.58
(0.54, 0.62)
<.0001
Parental Attitudes Toward Substance Use                        
     Multiple substance scale4 4.35
(3.80, 4.99)
<.0001 1.48
(1.22, 1.80)
.0001 2.06
(1.68, 2.52)
<.0001 1.89
(1.32, 2.71)
.0006 2.80
(2.49, 3.15)
<.0001 2.88
(2.53, 3.27)
<.0001
     Marijuana (try once or
     twice)
3.31
(2.99, 3.67)
<.0001 1.58
(1.31, 1.91)
<.0001 1.79
(1.48, 2.17)
<.0001 1.75
(1.27, 2.41)
<.0001 2.46
(2.22, 2.74)
<.0001 2.46
(2.19, 2.77)
<.0001
Parents Communicate About Substance Use 1.02
(0.91, 1.14)
.7016 1.01
(0.77, 1.33)
.9480 0.67
(0.53, 0.84)
.0006 0.83
(0.51, 1.35)
.4484 1.00
(0.89, 1.13)
.9528 0.94
(0.82, 1.07)
.3460
Parents Are Source of Social Support 0.37
(0.33, 0.41)
<.0001 0.53
0.40, 0.71)
<.0001 0.50
(0.39, 0.65)
<.0001 0.31
(0.20, 0.48)
<.0001 0.41
(0.36, 0.46)
<.0001 0.39
(0.34, 0.45)
<.0001
OR = odds ratio; CI = confidence interval.

1 "Other" includes those other than whites, blacks, and Hispanics (i.e., Asians, American Indians or Alaska Natives, or Native Hawaiians or other Pacific Islanders).
2 The questions used to measure each of the factors are provided in Appendix A (Table A.2). The coding and distribution of the responses for each factor are provided in Table 2.2.
3 ORs are based on separate logistic regression models of past year marijuana use for each of the factors, run separately for each of the categories of race/ethnicity and gender. ORs have not been adjusted for demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use.
4
Multiple substance scales take the mean of responses for marijuana, cigarette, and alcohol use.

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

Table 3.9 Unadjusted Odds Ratios and Confidence Intervals (95 Percent) of Peer/Individual Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17, by Race/Ethnicity and Gender: 1999

Peer/Individual Domain2 Race/Ethnicity Gender
Whites Blacks Hispanics Other1 Males Females
OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value
Antisocial Behavior 7.56
(6.07, 9.42)
<.0001 5.11
(3.62, 7.22)
<.0001 6.72
(4.44, 10.19)
<.0001 24.24
(10.04, 58.55)
<.0001 5.82
(4.74, 7.14)
<.0001 12.73
(9.59, 16.90)
<.0001
Individual Attitudes Toward Substance Use                        
     Multiple substance scale4 4.67
(4.33, 5.03)
<.0001 3.04
(2.58, 3.59)
<.0001 3.59
(2.99, 4.31)
<.0001 4.36
(3.32, 5.73)
<.0001 3.76
(3.44, 4.12)
<.0001 4.82
(4.40, 5.29)
<.0001
     Marijuana (try once or
     twice)
4.95
(4.59, 5.34)
<.0001 3.51
(3.01, 4.08)
<.0001 3.46
(2.93, 4.09)
<.0001 4.84
(3.62, 6.47)
<.0001 4.01
(3.68, 4.38)
<.0001 5.04
(4.60, 5.53)
<.0001
Friends' Attitudes Toward Substance Use                        
     Multiple substance scale4 4.76
(4.41, 5.14)
<.0001 2.67
(2.27, 3.13)
<.0001 3.54
(3.02, 4.16)
<.0001 4.89
(3.55, 6.73)
<.0001 3.71
(3.40, 4.05)
<.0001 4.95
(4.53, 5.42)
<.0001
     Marijuana (try once or
     twice)
4.96
(4.61, 5.33)
<.0001 3.07
(2.63, 3.59)
<.0001 3.46
(3.02, 3.97)
<.0001 4.74
(3.48, 6.47)
<.0001 3.86
(3.55, 4.19)
<.0001 5.09
(4.67, 5.54)
<.0001
Friends' Substance Use                        
     Multiple substance scale4 8.98
(8.15, 9.90)
<.0001 5.64
(4.58, 6.94)
<.0001 6.26
(4.97, 7.90)
<.0001 12.17
(7.75, 19.11)
<.0001 7.62
(6.81, 8.54)
<.0001 8.69
(7.67, 9.84)
<.0001
     Marijuana 7.14
(6.51, 7.82)
<.0001 4.93
(4.19, 5.80)
<.0001 4.81
(3.94, 5.87)
<.0001 6.97
(4.80, 10.11)
<.0001 5.85
(5.28, 6.47)
<.0001 6.77
(6.09, 7.52)
<.0001
Perceived Risk of Substance Use                        
     Multiple substance scale4 4.87
(4.44, 5.33)
<.0001 2.18
(1.85, 2.56)
<.0001 3.04
(2.55, 3.63)
<.0001 2.70
(1.99, 3.67)
<.0001 3.73
(1.99, 3.67)
<0.001 3.86
(3.49, 4.27)
<.0001
     Marijuana 4.02
(3.74, 4.32)
<.0001 2.50
(2.15, 2.92)
<.0001 2.92
(2.56, 3.34)
<.0001 3.07
(2.33, 4.04)
<.0001 3.54
(3.27, 3.84)
<0.001 3.44
(3.17, 3.73)
<.0001
Risk-Taking Proclivity 3.45
(3.18, 3.75)
<.0001 2.45
(2.02, 2.97)
<.0001 3.23
(2.63, 3.97)
<.0001 4.09
(2.62, 6.39)
<.0001 2.97
(2.69, 3.27)
<.0001 3.84
(3.46, 4.26)
<.0001
Participation in Two or More Extracurricular Activities 0.45
(0.40, 0.50)
<.0001 0.64
(0.48, 0.86)
.0035 0.70
(0.55, 0.87)
.0017 0.66
(0.42, 1.05)
.0815 0.51
(0.45, 0.57)
<.0001 0.54
(0.47, 0.62)
<.0001
Religiosity 0.44
(0.41, 0.47)
<.0001 0.60
(0.50, 0.72)
<.0001 0.57
(0.48, 0.67)
<.0001 0.56
(0.39, 0.82)
.0031 0.48
(0.44, 0.52)
<.0001 0.47
(0.43, 0.52)
<.0001
ORs = odds ratio; CI = confidence interval.

1 "Other" includes those other than whites, blacks, and Hispanics (i.e., Asians, American Indians or Alaska Natives, or Native Hawaiians or other Pacific Islanders).
2 The questions used to measure each of the factors are provided in Appendix A (Table A.3). The coding and distribution of the responses for each factor are provided in Table 2.3.
3 ORs are based on separate logistic regression models of past year marijuana use for each of the factors, run separately for each of the categories of race/ethnicity and gender. ORs have not been adjusted for demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use.
4 Multiple substance scales take the mean of responses for marijuana, cigarette, and alcohol use.

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

Table 3.10 Unadjusted Odds Ratios and Confidence Intervals (95 Percent) of School Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17, by Race/Ethnicity and Gender: 1999

School Domain2 Race/Ethnicity Gender
Whites Blacks Hispanics Other1 Males Females
OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value OR3
(95% CI)
p value
Commitment to School 0.43
(0.40, 0.47)
<.0001 0.58
(0.46, 0.74)
<.0001 0.43
(0.34, 0.54)
<.0001 0.32
(0.21, 0.51)
<.0001 0.53
(0.48, 0.58)
<.0001 0.37
(0.33, 0.41)
<.0001
Sanctions Against Substance Use at School                        
     Multiple substance scale4 0.26
(0.22, 0.30)
<.0001 0.39
(0.27, 0.56)
<.0001 0.37
(0.27, 0.51)
<.0001 0.14
(0.07, 0.28)
<.0001 0.28
(0.23, 0.34)
<.0001 0.29
(0.24, 0.34)
<.0001
     Illegal drugs 0.48
(0.41, 0.57)
<.0001 0.70
(0.47, 1.03)
.0719 0.61
(0.43, 0.86)
.0052 0.31
(0.15, 0.65)
.0019 0.51
(0.42, 0.61)
<.0001 0.54
(0.43, 0.67)
<.0001
Perceived Prevalence of Substance Use                        
     Multiple substance scale4 6.58
(5.80, 7.45)
<.0001 4.51
(3.57, 5.71)
<.0001 5.39
(4.14, 7.02)
<.0001 7.12
(4.15, 12.23)
<.0001 6.35
(5.53, 7.29)
<.0001 6.18
(5.35, 7.14)
<.0001
     Marijuana 5.31
(4.78, 5.90)
<.0001 3.59
(2.96, 4.34)
<.0001 4.83
(3.85, 6.07)
<.0001 4.73
(3.11, 7.19)
<.0001 4.71
(4.22, 5.25)
<.0001 5.01
(4.42, 5.66)
<.0001
Academic Performance 1.81
(1.69, 1.94)
<.0001 1.56
(1.29, 1.88)
<.0001 1.96
(1.65, 2.32)
<.0001 2.38
(1.69, 3.37)
<.0001 1.76
(1.61, 1.92)
<.0001 1.88
(1.73, 2.03)
<.0001
Exposure to Prevention Messages in School (Yes vs. No) 0.60
(0.53, 0.68)
<.0001 0.90
(0.64, 1.25)
.5197 0.55
(0.40, 0.74)
.0001 0.80
(0.44, 1.45)
.4588 0.62
(0.53, 0.71)
<.0001 0.66
(0.56, 0.78)
<.0001
OR = odds ratio; CI = confidence interval.

1 "Other" includes those other than whites, blacks, and Hispanics (i.e., Asians, American Indians or Alaska Natives, or Native Hawaiians or other Pacific Islanders).
2 The questions used to measure each of the factors are provided in Appendix A (Table A.4). The coding and distribution of the responses for each factor are provided in Table 2.4.
3 ORs are based on separate logistic regression models of past year marijuana use for each of the factors, run separately for each of the categories of race/ethnicity and gender. ORs have not been adjusted for demographic differences. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use.
4 Multiple substance scales take the mean of responses for marijuana, cigarette, and alcohol use.

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

Table 3.11 Adjusted Odds Ratios (Controlling for Demographics) and Confidence Intervals (95 Percent) of Community Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

Community Domain1 Odds of Past Year Marijuana Use
Risk/Protective Factor Adjusted OR2 p value 95% CI
Community Disorganization and Crime Risk 1.52 <.0001 (1.40, 1.65)
Neighborhood Cohesiveness Protective 0.86 <.0001 (0.81, 0.92)
Community Attitudes Toward Substance Use Risk      
     Multiple substance scale3   1.85 <.0001 (1.72, 1.99)
     Marijuana (try once or twice)   1.72 <.0001 (1.61, 1.84)
Community Norms Toward Substance Use Risk      
     Multiple substance scale3   4.52 <.0001 (4.07, 5.02)
     Marijuana (try once or twice)   3.72 <.0001 (3.41, 4.07)
Availability of Marijuana Risk 2.34 <.0001 (2.19, 2.51)
Exposed to Prevention Messages in the Media Protective 0.71 <.0001 (0.62, 0.80)
OR = odds ratio; CI = confidence interval.

1 The questions used to measure each of the factors are provided in Appendix A (Table A.1). The coding and distribution of the responses for each factor are provided in Table 2.1.
2 ORs are derived from multiple logistic regression models adjusted for age, gender, race/ethnicity, number of parents in home, household income, county type, and geographic region. ORs are based on separate logistic regression models of past year marijuana use for each of the factors. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use.
3 Multiple substance scales take the mean of responses for marijuana, cigarettes, and alcohol.

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

Table 3.12 Adjusted Odds Ratios (Controlling for Demographics) and Confidence Intervals (95 Percent) of Family Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

Family Domain1 Odds of Past Year Marijuana Use
Risk/Protective Factor Adjusted OR2 p value 95% CI
Parental Monitoring Risk 1.97 <.0001 (1.81, 2.15)
Parental Encouragement Protective 0.64 <.0001 (0.60, 0.67)
Parental Attitudes Toward Substance Use Risk      
     Multiple substance scale3   2.63 <.0001 (2.38, 2.90)
     Marijuana (try once or twice)   2.31 <.0001 (2.12, 2.52)
Parents Communicate About Substance Use Protective 1.01 .8652 (0.91, 1.11)
Parents Are Source of Social Support

Protective

0.44 <.0001 (0.40, 0.49)
OR = odds ratio; CI = confidence interval.

1 The questions used to measure each of the factors are provided in Appendix A (Table A.2). The coding and distribution of the responses for each factor are provided in Table 2.2.
2 ORs are derived from multiple logistic regression models adjusted for age, gender, race/ethnicity, number of parents in home, household income, county type, and geographic region. ORs are based on separate logistic regression models of past year marijuana use for each of the factors. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use.
3 Multiple substance scales take the mean of responses for marijuana, cigarettes, and alcohol.

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

Table 3.13 Adjusted Odds Ratios (Controlling for Demographics) and Confidence Intervals (95 Percent) of Peer/Individual Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

Peer/Individual Domain1 Odds of Past Year Marijuana Use
Risk/Protective Factor Adjusted OR2 p value 95% CI
Antisocial Behavior Risk 8.01 <.0001 (6.64, 9.66)
Individual Attitudes Toward Substance Use Risk      
     Multiple substance scale3   3.85 <.0001 (3.59, 4.13)
     Marijuana (try once or twice)   3.93 <.0001 (3.67, 4.20)
Friends' Attitudes Toward Substance Use Risk      
     Multiple substance scale3   3.76 <.0001 (3.51, 4.02)
     Marijuana (try once or twice)   3.83 <.0001 (3.60, 4.07)
Friends' Substance Use Risk      
     Multiple substance scale2   6.74 <.0001 (6.16, 7.38)
     Marijuana   5.39 <.0001 (4.99, 5.83)
Perceived Risk of Substance Use Risk      
     Multiple substance use3   3.82 <.0001 (3.52, 4.14)
     Marijuana   3.23 <.0001 (3.04, 3.43)
Risk-Taking Proclivity Risk 3.20 <.0001 (2.97, 3.45)
Participation in Two or More Extracurricular Activities Protective 0.58 <.0001 (0.52, 0.64)
Religiosity Protective 0.54 <.0001 (0.50, 0.57)
OR = odds ratio; CI = confidence interval.

1 The questions used to measure each of the factors are provided in Appendix A (Table A.3). The coding and distribution of the responses for each factor are provided in Table 2.3.
2 ORs are derived from multiple logistic regression models adjusted for age, gender, race/ethnicity, number of parents in home, household income, county type, and geographic region. ORs are based on separate logistic regression models of past year marijuana use for each of the factors. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use.
3 Multiple substance scales take the mean of responses for marijuana, cigarettes, and alcohol.

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

Table 3.14 Adjusted Odds Ratios (Controlling for Demographics) and Confidence Intervals (95 Percent) of School Domain Risk and Protective Factors and Past Year Use of Marijuana among Youths Aged 12 to 17: 1999

School Domain1 Odds of Past Year Marijuana Use
Risk/Protective Factor Adjusted OR2 p value 95% CI
Commitment to School Protective 0.46 <.0001 (0.43, 0.50)
Sanctions Against Substance Use at School Protective      
     Multiple substance scale3   0.44 <.0001 (0.38, 0.51)
     Illegal drugs   0.60 <.0001 (0.52, 0.70)
Perceived Prevalence of Substance Use Risk      
     Multiple substance scale3   4.76 <.0001 (4.24, 5.33)
     Marijuana   4.07 <.0001 (3.72, 4.46)
Academic Performance Risk 1.77 <.0001 (1.65, 1.89)
Exposed to Prevention Messages in School Protective 0.77 <.0001 (0.69, 0.87)
OR = odds ratio; CI = confidence interval.

1 The questions used to measure each of the factors are provided in Appendix A (Table A.4). The coding and distribution of the responses for each factor are provided in Table 2.4.
2 ORs are derived from multiple logistic regression models adjusted for age, gender, race/ethnicity, number of parents in home, household income, county type, and geographic region. ORs are based on separate logistic regression models of past year marijuana use for each of the factors. ORs > 1.0 indicate that the odds of past year marijuana use increased with each unit increase in the predictor. For risk factors, each unit increase in the predictor generally indicates an increased risk of marijuana use. For protective factors, each unit increase in the predictor generally indicates a higher level of protection against marijuana use.
3 Multiple substance scales take the mean of responses for marijuana, cigarettes, and alcohol.

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

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This page was last updated on July 17, 2008.