In Chapter 3, we briefly discussed past year marijuana use by exposure to prevention messages. For two of the prevention factors, youths with the factors had higher levels of past year marijuana use, which was an unexpected finding. In particular, "talking with parents or another adult about alcohol or drug use" and "hearing prevention messages on television or on radio" were associated with either no differences or higher levels of past year marijuana use rather than lower levels.
In this appendix, we look at some possible confounding factors as explanations for the apparent anomaly. We present the cross-tabulations of each of the prevention "messages" by gender, timing of the onset of substance use, and amount of arguing with parents in Tables E.1 to E.3, respectively. For the sake of completeness, we also include in the tables the results of prevention messages delivered in school alcohol/drug education classes even though they were associated with lower levels of past year marijuana use, as expected.
Our first hypothesis was that gender differences might explain the anomalous findings. For example, if males had a higher prevalence rate of marijuana use than females and more males indicated they had spoken to a parent or other adult about alcohol or drugs than males who had not spoken to a parent about drugs, this could help explain the anomaly. However, the prevalence levels for males were similar whether the youth had spoken to a parent or other adult about drugs or alcohol or not, and the number of males in each category was similar (Table E.1). The same was true for females. For alcohol/drug prevention messages outside of school, 15.3 percent of males who had been exposed to this type of prevention message reported past year marijuana use, similar to the 14.3 percent for males who had no such exposure. On the other hand, a much larger percentage of females who indicated they had seen or heard a prevention message outside of school reported past year use of marijuana (16 percent) than did those who had not been exposed to this type of message (8.6 percent).
We hypothesized that the timing of the drug/alcohol conversation with a parent was all-important. Because we are trying to relate a past year conversation with past year marijuana use, the question of which came first is crucial. Perhaps the nature of the conversation about drugs for those youths who had started using drugs 2 or more years ago might be more in the form of an argument about use than a "prevention" message, so that it would not constitute a true prevention message. There is some evidence that this was part of the cause for the higher prevalence of marijuana use among those indicating their onset of substance use was at least 2 years earlier compared to those who had either never started substance use or who had started less than 2 years earlier. Among individuals reporting onset of alcohol, marijuana, or any other illicit substance use 2 or more years earlier and who had spoken to a parent or other adult about alcohol or drugs in the past year, 49.1 percent were past year marijuana users versus only 42.3 percent for those who had not spoken to a parent or other adult about alcohol or drugs (Table E.2). In other words, possibly part of the explanation for higher prevalence levels among youth who spoke to a parent or other adult about alcohol or drugs is that a number were already using these substances when the conversation took place. However, this group is relatively small, an estimated 5 million youths out of the total 22 million in the population, and does not entirely explain the overall result. Among the other 16 million who had never used alcohol, marijuana, or any other illicit substance or whose onset of use was less than 2 years ago, the prevalence of past yearmarijuana use was similar for those who had spoken and those who had not spoken to a parent or adult about alcohol or drugs (5.2 percent and 4.8 percent, respectively).
For individuals who started substance use at least 2 years earlier, there was no difference between those who heard an alcohol/drug prevention message outside of school and those who had not (46.1 vs. 46.7 percent, respectively). For those individuals who either had not started substance use and those whose use started less than 2 years earlier, there was a slight difference between the individuals who had and those who had not been exposed to this prevention message (5.3 vs. 3.5 percent, respectively).
The final hypothesis had to do with having frequent or infrequent arguments with parents, with the reasoning that speaking with a parent about drugs or alcohol could be more in the form of an argument about drug use and other behavior, and that those youths might report higher prevalence rates of past year marijuana use. However, for youths who argued frequently, the prevalence rates for those who had spoken to a parent about alcohol or drug use and those who had not were similar (both about 22 percent), and for youths who argued infrequently, a slightly higher prevalence rate was reported by those who had spoken with a parent or other adult (14.3 percent) than those who had not spoken to a parent (10.9 percent) (Table E.3). For adolescents who argued weekly with their parents and for those who did not, having seen or heard an alcohol or drug prevention message outside of school was associated with higher rates of marijuana use.
To summarize, the hypotheses that we explored for the unexpected findings did not explain why youths who heard an alcohol/drug prevention message outside of school reported higher prevalence levels of past year marijuana use, but did suggest a partial explanation of the reason why youths who have had a discussion with a parent or adult about alcohol/drugs reported higher levels. The latter may be due to the fact that some youths may have already started use of marijuana before the discussion. In this case, the discussion may be less of a prevention message and more of an argument. Further analysis is needed to better understand these results. At a minimum, this analysis would profit by a question that establishes for each youth whether the prevention "message" was heard or delivered before or after first use of a drug.
Prevention Message |
N (in 1,000s) |
Prevalence of Past Year Marijuana Use |
Spoken with Parent/Other Adult About Drugs/Alcohol in Past Year | ||
Yes |
11,977 |
16.0 |
Male |
5,857 |
16.5 |
Female |
6,120 |
15.5 |
No |
9,984 |
14.0 |
Male |
5,371 |
13.3 |
Female |
4,613 |
14.8 |
In-School Alcohol/Drug Education Class in Past Year | ||
Yes |
11,763 |
12.6 |
Male |
6,340 |
11.8 |
Female |
6,423 |
13.4 |
No |
9,620 |
18.6 |
Male |
5,045 |
19.3 |
Female |
4,576 |
17.8 |
Seen/Heard Alcohol/Drug Prevention Messages Outside of School in Past Year | ||
Yes |
18,657 |
15.7 |
Male |
9,239 |
15.3 |
Female |
9,419 |
16.0 |
No |
3,384 |
12.0 |
Male |
2,027 |
14.3 |
Female |
1,357 |
8.6 |
Note: Data in table read "16.5 percent of male youths who had spoken with a parent or other adult about drugs or alcohol in the past year used marijuana in the past year."
Source: Office of Applied Studies, SAMHSA, 1997 National Household Survey on Drug Abuse.
Prevention Message |
N (in 1,000s) |
Prevalence of Past Year Marijuana Use |
Spoken with Parent/Other Adult About Drugs/Alcohol in Past Year | ||
Yes |
11,977 |
16.0 |
Onset substance use 2+ years ago1 |
2,956 |
49.1 |
Onset substance use not 2+ years ago2 |
9,022 |
5.2 |
No |
9,984 |
14.0 |
Onset substance use 2+ years ago |
2,449 |
42.3 |
Onset substance use not 2+ years ago |
7,535 |
4.8 |
In-School Alcohol/Drug Education Class in Past Year | ||
Yes |
12,762 |
12.6 |
Onset substance use 2+ years ago |
2,774 |
41.2 |
Onset substance use not 2+ years ago |
9,988 |
4.7 |
No |
9,620 |
18.6 |
Onset substance use 2+ years ago |
2,709 |
51.8 |
Onset substance use not 2+ years ago |
6,911 |
5.5 |
Seen/Heard Alcohol/Drug Prevention Messages Outside of School in Past Year | ||
Yes |
18,657 |
15.7 |
Onset substance use 2+ years ago |
4,751 |
46.1 |
Onset substance use not 2+ years ago |
13,906 |
5.3 |
No |
3,384 |
12.0 |
Onset substance use 2+ years ago |
671 |
46.7 |
Onset substance use not 2+ years ago |
2,713 |
3.5 |
Note: Data in table read "49.1 percent of youths who had spoken with a parent or other adult about drugs or alcohol in the past year and who started substance use 2+ years earlier, used marijuana in the past year."
1Onset of use of alcohol, marijuana, and other illicit substances.
2Includes both individuals who never started alcohol, marijuana, and other illicit substance use and individuals who started using any of these substances less than 2 years earlier.
Source: Office of Applied Studies, SAMHSA, 1997 National Household Survey on Drug Abuse.
Prevention Message |
N (in 1,000s) |
Prevalence of Past Year Marijuana Use |
Spoken with Parent/Other Adult About Drugs/Alcohol in Past Year | ||
Yes |
11,869 |
16.0 |
Argued weekly with parents |
2,807 |
21.6 |
Argued with parents less than weekly |
9,062 |
14.3 |
No |
9,868 |
13.9 |
Argued weekly with parents |
2,680 |
22.0 |
Argued with parents less than weekly |
7,188 |
10.9 |
In-School Alcohol/Drug Education Class in Past Year | ||
Yes |
12,700 |
12.6 |
Argued weekly with parents |
3,114 |
16.8 |
Argued with parents less than weekly |
9,586 |
11.2 |
No |
9,193 |
18.6 |
Argued weekly with parents |
2,396 |
28.0 |
Argued with parents less than weekly |
6,797 |
15.3 |
Seen/Heard Alcohol/Drug Prevention Messages Outside of School in Past Year | ||
Yes |
18,520 |
15.6 |
Argued weekly with parents |
4,588 |
22.9 |
Argued with parents less than weekly |
13,932 |
13.2 |
No |
3,280 |
12.2 |
Argued weekly with parents |
897 |
15.7 |
Argued with parents less than weekly |
2,384 |
10.9 |
Note: Data in table read "21.6 percent of youths who had spoken with a parent or other adult about drugs or alcohol in the past year and who argued weekly with their parents, used marijuana in the past year."
Source: Office of Applied Studies, SAMHSA, 1997 National Household Survey on Drug Abuse.
This page was last updated on June 01, 2008. |
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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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