With ten regressions, examining the impact of five different adolescent risky behaviors with four different age categories each can be daunting. Seeming inconsistencies must be considered in the broad scheme; many of these are due to small cell sizes. We interpret the findings with an eye toward the big picture. To draw conclusions, we look at patterns of relationships across the different outcome domains. Most of the findings we cite in this report have p-values of 0.1 or less, a conventional level of statistical significance. However, while we consider statistical significance important, we do not rely on statistical significance alone. Because this study is exploratory in nature, we use p-values of 0.1 as a guideline.
Our techniques generally compare outcomes for three age of initiation groups (or numbers of delinquent/criminal acts) with a reference group (ages 11-15 or 9 or more acts). We base our judgments on whether a set of odds ratios or marginal effects generally go in the same direction when compared with the reference group, i.e. if the outcomes for each group are all better or worse than the reference group. Generally, if all the values are going in the same direction, then if the comparison for at least one of the other groups achieves significance we consider the relationship to hold. In the economic domain, where there are multiple outcomes, we see common relationships across the different outcome variables. When they all are nearly the same, we consider this confirming evidence of a relationship for the entire domain. We attempt to notify the reader when we are describing a general pattern, but where statistical significance does not always hold. It is important to note that all estimated relationships are associations between variables; nothing should be construed as a causal relationship. To understand causality would require an extensive model of behavior with many more measures than are available to us.
Despite some occasional oddities, a clear picture emerges as to the relationship of these five behaviors to the various outcomes. We report our findings by looking at the relationship of various adolescent risky behaviors to each adult outcome.
Adolescent alcohol usage. As seen in Figure 1, age of initiation into alcohol consumption is very much associated with having an alcohol abuse or dependence problem as an adult in the past year. To interpret Figure 1, recall that ages 11-15 are the reference group. Their odds ratio is set equal to one. Odds ratios for other age groups are relative to those who initiated between ages 11-15. Thus, those who initiated at ages 16-17 are only 88 percent as likely to have an adult alcohol abuse or dependence problem compared with those who initiated between ages 11=15. Those who initiated at ages 18-19 are only 56 percent as likely, and those who had not initiated by age 19 are only 23 percent as likely.
It is not too surprising to find such a strong relationship since adolescent use of alcohol is clearly the most closely related behavior to the possible consequence. Quite clearly, the earlier one initiates into alcohol use, the more likely one has an alcohol problem as an adult. This result is consistent with other research that has found a link between early alcohol initiation and adult alcohol problems (Chou and Pickering, 1992; Grant and Dawson, 1997).
Figure 1.Odds Ratios for Age of Alcohol Initiation As it Relates to Alcohol Abuse or Dependence
The use of alcohol and drugs are different behaviors among adolescents. Adolescents consuming alcohol may never use drugs. Although early adolescent alcohol use may increase the likelihood of an adult alcohol problem, it may imply nothing about adult drug problems. In our findings, there are no real differences in the likelihood of an adult drug problem among the three lower age groups. However, not using alcohol by age 19 is associated with much lower likelihood of having a drug problem as an adult. Thus those who do not engage in alcohol use as teenagers are those most likely to avoid both long-term alcohol and long-term drug problems.
Although alcohol consumption in adolescence is associated with negative health outcomes, it generally is not associated with bad economic, family formation, or incarceration outcomes. Compared with all the other behaviors we study, adolescent alcohol usage has the least association with long-term outcomes. These findings together with those from Newcomb and Bentler (1988) point to the idea that the impact of early alcohol use may portend less serious adult consequences than does engaging in other forms of risky behavior as an adolescent. On the other hand, we have measured only the direct effects of adolescent alcohol initiation. If early alcohol use increases the likelihood of other risky behaviors such as sexual activity, then there may be an indirect relationship with adult outcomes.
Adolescent marijuana usage. Like adolescent alcohol use, engaging in marijuana use as an adolescent has a strong relationship with the adult outcome of most direct consequence. That is, earlier use of marijuana implies a greater likelihood of using drugs as an adult. As seen in Figure 2, those who initiate marijuana usage at ages 16-17 are 76 percent as likely to use drugs as an adult compared with those who initiated before age 16. Those who initiated at ages 18-19 are 88 percent16 as likely and those who did not initiate by age 19 are only 28 percent as likely.
Figure 2. Odds Ratios for Age of Marijuana Initiation As it Relates to Past Month Drug Use at Age 30
Initiation as a teenager implies greater likelihood of adult alcohol abuse or dependence, but within the teenage years there is little distinction. Unlike alcohol, engaging in marijuana use as an adolescent is generally associated with bad economic outcomes. For example, Figure 3 shows the relationship between age of marijuana initiation and the likelihood of being in poverty between ages 25-29.
Figure 3. Odds Ratios for Age of Marijuana Initiation as it Relates to Ever Being in Poverty Between Ages 25-29
Those who initiate in the 18-19 age group are 79 percent as likely to be in poverty as those who initiate between ages 11-15. This age group is consistently less prone to incur bad outcomes for the other economic measures than those who initiate earlier. Oddly, those who have had not initiated by age 19 are statistically no different than the earliest initiators. This is true nearly always across the economic outcomes. We do not have an explanation for this. Since late initiators are combined with those who never initiate, there may be some impact of late initiation that is pulling down the average outcome for this group. Late initiation is likely a different phenomenon than early initiation, perhaps resulting from bad economic circumstances rather than preceding them.17
The pattern for the likelihood of spending time in jail, however, is consistent; the earlier one initiates marijuana use, the more likely they spend time in jail.
For the relationship between age of initiation into marijuana use and adult family formation, only one odds ratio achieves a reasonable level of statistical significance. Overall this implies that the relationship is the same regardless of age of initiation.
Adolescent cocaine usage. Many young people experiment with both alcohol and marijuana, but cocaine use is rarer (see Table 2). Its usage also tends to begin at later ages. As a result some of the cell sizes in our estimations are small. However, a clear pattern emerges showing that those who begin using cocaine as teenagers have worse economic, health, and incarceration outcomes. It is more difficult to interpret the results for family formation. Teenage cocaine users are no more likely than non-users to end up as single parents or divorced. However, it is clear that they are the most likely to end up as never having married without children and least likely to end up married with children. This implies that teenage cocaine users do not have non-marital births or get divorced primarily because they are least likely to be able to form solid relationships in the first place. Overall they are the least likely to marry and the least likely to have children (regardless of marital status) than those who do not use cocaine as teenagers.
Adolescent sexual activity. Age of initiation into sexual intercourse is perhaps the most consistent predictor of poor adult outcomes across nearly every domain. Unlike any other behavior studied, the results have near perfect consistency with no anomalies. Not only is engaging in sex as a teenager associated with bad outcomes in general, earlier ages of initiation are consistently increasingly associated with poorer outcomes. This is true for all six measures of economic success and for the probability of spending time in jail. Similarly, early sex initiators have poorer family formation outcomes. The predicted probabilities of each outcome for each age group are shown in Figure 4. The earlier a youth begins engaging in sexual activity, the more likely he or she ends up never married with a child. Specifically, we predict 11.2 percent of those who initiated sex between ages 11-15 to be never married with children at age 33. Of those who initiate at ages 16-17, we predict 8.7 percent will be never married with children at age 33; 7.5 percent of those who initiate at ages 18-19 and 4.2 percent of those who do not initiate by age 19. In general, early sex initiators are more likely to marry by age 33 than are those who wait. Over 79 percent of those who initiated by age 17 had married while about 76 percent of those who initiated at ages 18-19 and 67.4 percent of those who had not initiated by age 19 had married by age 33. Of those who marry by age 33, divorce rates are predicted to be higher the earlier there had been sex initiation. 36.2 percent of those who initiated between ages 11-15, 31.1 percent of those who initiated at ages 16-17, 23.5 percent of those who initiated at ages 18-19, and 14.2 percent of those who had not initiated by age 19 are predicted to be divorced by age 33.18 Not surprisingly, those who initiated sex earlier are predicted to be more likely to have children by age 33, regardless of their marital history. By age 33, 77.1 percent of those who initiated sex between ages 11-15 are predicted to have children; 72.6 percent of those who initiated at ages 16-17; 67.4 percent of those who initiated at ages 18-19; and 53.3 percent of those who had not initiated by age 19.
Figure 4. Predicted Probabilities of Marriage-Fertility Outcomes At Age 33 as They Relate to Age of Sex Initiation
The health domain as measured by adult alcohol and drug problems is least related to early sexual activity. Those who do not engage in sex as teenagers are less likely to have an adult alcohol problem, but there is no distinction in the likelihood across the teenage years. Those who initiate after age 17 are less likely to use drugs as an adult; those who initiate after 19 are least likely. There is no distinction for those who initiate before age 18. Although there isn't as strong a relationship between age of sex initiation and the two health measures, it is still the case that teenage sex initiators are more likely to have adult alcohol and drug problems.
Adolescent delinquency. Committing delinquent and criminal acts as an adolescent is associated with mostly bad adult outcomes. As expected, the more delinquent acts committed, the more likely the youth spends time in jail by age 33. A similar result is found for the likelihood of having an adult alcohol or drug problem. These results are comparable with Windle's (1990) where, even when controlling for early substance use, early delinquency was predictive of later substance use. These three adult outcomes have consistent results across the levels of delinquency.
Some of the other results bounce around a bit, possibly a consequence of noise in our measure. However, isolating those who committed nine or more delinquent or criminal acts shows they definitely have worse economic outcomes than do others. This holds true across all six economic measures. One of the stronger relationships is with the likelihood of ever being on welfare between ages 21-33, shown in Figure 5. Those who did not commit any delinquent acts are 69 percent as likely to ever be on welfare during those ages compared to those who committed nine or more delinquent acts; those who committed one or two delinquent acts are 80 percent as likely; and those who committed 3-8 delinquent acts are 83 percent as likely. All three differences are statistically significant at the 90 percent confidence level or higher. Past research on the connection between delinquency and economic outcomes has been mixed. After controlling for education and other background variables, Monk-Turner (1989) could find no relationship between delinquency and adult occupational status. In our study, when holding education and other variables constant, we were able to observe a significant impact of delinquency on a variety of economic measures.
Figure 5. Odds Ratios for Number of Delinquent Acts as it Relates to Ever Being on Welfare Between Ages 21-33
In terms of family formation, there are some consistent results. The more delinquent acts performed, the more likely the person ends up never married with a child and the least likely they are to end up married with children. In general, they are less likely to marry and more likely to divorce if they marry.
To summarize, we have examined the relationship between five adolescent risky behaviors and ten adult outcomes. There is a fairly consistent pattern that engaging
in risky behaviors as a teenager is associated with less successful adult outcomes. For many, the relationship is such that the earlier one engages in the behavior, the more likely they face a bad outcome as an adult. The most consistent predictor of a bad adult outcome is age of initiation into sexual activity. Alcohol usage, on the other hand, is perhaps the one teenage behavior least associated with bad adult outcomes. Age of initiation into alcohol usage is, however, associated with adult alcohol abuse or dependence. These relationships should not be interpreted as causal, but only as associations. Other factors that are not controlled for may influence these outcomes. Age of initiation may be capturing unmeasured adolescent characteristics or circumstances that are related to the transition into adulthood. The summary below provides a more detailed description of the findings in this section.
- Age of initiation into adolescent alcohol use is associated with adult alcohol disorders and teenage use is associated with adult drug usage. However, there is no relationship between adolescent alcohol use and adult economic, family, or incarceration outcomes.
- Age of initiation into marijuana use is associated with adult drug usage, bad adult economic and incarceration outcomes. Teenage usage is associated with adult alcohol disorders but adolescent marijuana use is not associated with any specific adult family formation outcomes.
- Teenage cocaine use is associated with worse economic, health, and incarceration outcomes. They are the least likely to marry or have children by age 33.
- Age of initiation into sexual intercourse is the most consistent predictor of poor adult outcomes across nearly every domain, especially economic and incarceration outcomes. They are the most likely to have never married but have a child by age 33. Those who marry by age 33 are the most likely to divorce.
- Committing more delinquent acts is associated with bad adult alcohol, drug, and incarceration outcomes. Committing nine or more delinquent acts is associated with worse economic outcomes. Those committing nine or more delinquent acts are also the least likely to marry, the most likely to divorce, and the most likely to have never married but have a child at age 33.