Predictors of Trajectory Subgroup Membership

by National Institute of Health

(Page 4 of 4)

Several studies show that whether adolescents or young adults should be designated as belonging in heavier-drinking subgroups can be predicted by whether or not they have several preexisting personal and social - environmental characteristics: being male, not living with two biological parents, and having parents with heavier alcohol use and greater symptoms of alcoholism or antisocial personality. During late adolescence and early adulthood, male heavy drinkers are especially likely to have already exhibited externalizing symptoms such as aggressive behaviors and early delinquent behavior.

Alcohol-related factors that predict whether young people will embark on subsequent heavier-drinking trajectories include the degree to which they have more positive expectancies about alcohol's effects, whether they think it is all right to drink to get drunk or drink to cope with stressful situations, and whether they have prior alcohol and drug use.

Other risk factors include certain personal characteristics, involvement with social institutions, and peer influence. People who have such personal attributes as higher sensation-seeking and lower conventionality, self-esteem, and self-efficacy also are at risk for following heavier-drinking trajectories. Low involvement with social institutions also is associated with greater risk; for example, students with poorer performance in school, lack of commitment to attending classes, and less church involvement are more likely to be in heavy-drinking subgroups. Finally, peer factors are important predictors of riskier trajectories, with peer alcohol use, perceived peer approval of substance use, and less resistance to peer pressure each predicting heavier alcohol use. These risk factors are similar to those observed in more traditional cross-sectional and longitudinal research.

Trajectory Outcomes for Young Adults

A series of recent studies has examined whether young adults' health or the rate at which they attain various social roles is affected by their trajectories of alcohol use.

Research indicates that high school students who do not drink heavily are more likely to complete high school and attend college than their peers who do drink heavily. However, many young people only begin binge drinking or drinking heavily during college.

Criminal behavior, including stealing, selling drugs, and committing violent acts, is more prevalent among heavier drinkers in general. Binge drinkers also are more likely to exhibit symptoms of antisocial personality disorder than people who do not binge drink. However, compared with young people who rarely use alcohol, fling drinkers - whose heavy drinking spikes during late adolescence and young adulthood and then declines - tend to have equivalent psychosocial adjustment during adulthood.

Health in young adulthood also differs by alcohol use trajectories. One study found that at age 24, people who had been classified as chronic heavy drinkers based on their trajectories of drinking in adolescence had increased risk for obesity, hypertension, and illness, compared with peers who had not been heavy drinkers during adolescence. These findings were maintained even when gender, ethnicity, poverty, and current level of alcohol and other substance use were statistically controlled. Chronic binge drinkers and late-onset drinkers also reported more sex partners by age 21 than nonbinge drinkers. People who were not binge drinkers had the most positive health behaviors and status, and increasers and late-onset binge drinkers generally fell between the chronic binge and nonbinge drinking groups in terms of this variable. Risk for alcohol and other drug abuse and dependence in young adulthood is lowest among people who do not engage in heavy episodic, or binge, drinking. Many studies show few or no health differences between light drinkers and abstainers, although some research suggests that health and personal relationships may be more positive among light drinkers than among abstainers.

Conclusions

Several conclusions from these longitudinal studies on alcohol use trajectories deserve to be highlighted. First, many adolescents and young adults never engage in heavy drinking. Although the majority of people report some alcohol use, significant numbers never report drinking heavily at any assessment period. Although the proportion of young people who never drink heavily remains uncertain, studies indicate that it is somewhere between one-third and more than two-thirds, depending on sample characteristics and the definition of heavy drinking used.

Second, the age when drinking begins is important. Meaningful differences in the predictors, course, and consequences of alcohol use can be found between the subgroup of people who begin drinking in early adolescence and those who begin drinking during middle or later adolescence. Later onset of developmentally limited heavy drinking is more common than early onset, is associated with fewer early risk factors, and is determined more by situational and developmentally normative risk factors such as living with peers in college residences. However, later onset of heavy drinking also carries health and other risks, as described previously.

Third, members of most subgroups reduce their alcohol use by their mid-twenties. Declines in use are associated with acquiring adult roles, such as spouse, parent, and worker.

Fourth, young people who consistently drink heavily, although few in number, have the most early and ongoing risk factors for behavioral and adjustment difficulties generally and the fewest positive adult outcomes.

Fifth, early but infrequent binge drinkers may be at risk for late-onset alcohol problems associated with negative affect regulation.

Implications for Prevention and Intervention

What do the concepts of normative and multiple trajectories of alcohol use mean for prevention? The study of trajectory approaches has reinforced the ideas that people develop in multiple dimensions across the adolescent and young adult years, alcohol use behaviors change differently for different people, and factors that predict alcohol use patterns also emerge and disappear at different ages. For these reasons, multiple dynamic approaches to prevention and intervention are needed. Clearly, one approach will not fit all needs. For example, early onset of infrequent use associated with negative affect may be rare, but the pattern deserves attention because young people who fit this trajectory are at risk for longer-term problems, including depression. Early onset of substance use predicts ongoing heavier use and associated difficulties for many, so middle-school drug use prevention programs are appropriate for this subgroup. Likewise, late onset of alcohol and other drug use with escalation also is harmful, so prevention and intervention efforts in high school and beyond also are needed. Recognizing the varied and dynamic trajectories that alcohol use can take, rather than viewing drinking as a static behavior, offers a stronger developmental foundation for effective interventions.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.