Drug abuse prevention research parallels recent trends in mental and physical health promotion and the emerging new discipline of prevention science (Coie et al., 1993; IOM, 1994b). This enterprise requires the integration of epidemiological, etiological, and preventive intervention research. As applied to drug abuse, prevention science began in the mid- to late 1970s with attempts to prevent cigarette smoking among adolescents. The early focus was on changing the individual rather than the environment, and interventions usually occurred in schools.
Public health officials categorize preventive interventions based on when the intervention occurs: primary prevention involves intervening before the behavior appears; secondary prevention involves intervening after the onset of the behavior but before it becomes habitual; tertiary prevention involves intervening after the behavior has become habitual, with the goal of reducing or eliminating the behavior. Since 1990, a second model has been used increasingly to supplement these public health categories for preventive interventions: universal (delivered to the general population); selective (targeted at those presumed to be most ''at risk"); and indicated (targeted at those who are exhibiting some clinically demonstrable abnormality, though perhaps not the "disease" itself) (Gordon, 1983; IOM, 1994b). In the past 10 to 15 years there has been substantial interest in prevention programs in the United States, particularly school-based intervention. Almost all of these programs can be characterized as "primary" and "universal," where the goal is to reduce the incidence and prevalence of drug use. However, there is an ongoing debate
regarding the wisdom of continued emphasis on (and dedication of resources to) primary and universal prevention (focused on prevention of use) at the expense of secondary and selective prevention (focused on prevention of abuse and dependence). As the committee notes throughout this report, more information is needed about the serious problems of drug abuse and dependence.
Experimenting with drugs, particularly alcohol and tobacco products, is woven into the developmental life cycle. Well over half of all youth try these two drugs, which are legal commodities for adults. However, most youth do not regularly use illegal drugs, and most of those who have used them do not make the transition to drug abuse or dependence. Thus, it is unclear whether drug use per se is the most appropriate target of intervention. Moreover, the effects of primary prevention are usually too small to have a significant overall impact on drug abuse and dependence in the society. Given limited resources and shrinking budgets at the federal and state levels, it may be more important to focus on abuse and dependence.
Those who argue for the importance of primary and universal prevention efforts note that all young people are at risk for experimenting with alcohol, tobacco, and illicit drugs. They believe it would be irresponsible not to provide them with preventive interventions, since there can be negative consequences associated with even infrequent use (e.g., alcohol-impaired driving). Further, the etiology of drug use is complex, and targeting prevention to a "select" sample of youth would yield far too many "false positives." Such an approach could lead to inappropriate labeling and the possibility of missing some adolescents who need preventive interventions. Finally, a universal orientation is thought to be more cost-effective and logistically feasible given the structure of school systems (i.e., it is less expensive to provide everyone with the intervention than to selectively recruit those most at risk).
Despite the debate about the relative value of universal and selective interventions, they do not have to be viewed as mutually exclusive. In fact, it is more fruitful to view them as mutually supportive rather than competing alternatives. For example, universal interventions can promote antidrug norms in the larger society, and selective interventions can then build on universal preventive messages. Moreover, preventive intervention messages designed specifically for high-risk youth can be delivered within the context of universal prevention programs, avoiding the risk of harmful labeling. Both universal and targeted interventions have promise for prevention science but require more careful examination.
For almost 20 years, researchers in the United States have been systematically evaluating strategies designed to prevent or delay the onset of drug use among youth, mostly through school-based programs. These programs have been organized into five types: (1) information and values clarification, (2) affective education, (3) social influence, (4) comprehensive, and (5) providing alternatives to drug use (see Hansen, 1992).
The scientific basis for understanding how to prevent adolescent drug use has expanded considerably in a very short time, and valuable lessons have been learned. For example, some program types (information and values clarification, affective education, and alternatives to drug use) have virtually no effect on preventing the use of alcohol, tobacco, or illicit drugs (see Tobler, 1992; IOM, 1994a). However, in spite of consistent scientific evidence of minimal impact, such programs are often chosen as prevention interventions for children in schools. A prominent example is D.A.R.E. (Drug Abuse Resistance Education), the most widely disseminated school-based drug abuse prevention program in the United States (Ennett et al., 1994a; Ringwalt et al., 1994). Evaluations of D.A.R.E. consistently show only short-term effects on knowledge, attitudes, and drug use, and these effects decay within a year or so (Ennett et al., 1994b).
The failure of early school-based prevention programming to produce significant long-term effects has led to creative attempts to develop interventions focused on several known risk factors for drug use, including deficits in social and peer resistance skills and misperceptions about the extent of drug use among peers. These social influence programs have been rigorously evaluated scientifically and have been closely tied to psychosocial theoretical models of drug use initiation. School-based social influence programs have shown short-term success in reducing the prevalence of adolescent cigarette smoking (IOM, 1994a; U.S. DHHS, 1994), alcohol use (Dielman et al., 1992), and marijuana use (Ellickson and Bell, 1990, 1992; Hansen and Graham, 1991; Ellickson et al., 1993). However, most program effects lessen with time, and long-term outcomes have been disappointing (Murray et al., 1989; Ellickson et al., 1993). A number of the reasons that program effects may subside have been identified: insufficient dose, insufficient implementation, inappropriate expectations, curriculum limitations, attrition of high-risk students, inappropriate assumptions about age at onset, and inappropriate messages (Resnicow and Botvin, 1993).
Two school-based prevention interventions that have demonstrated long-term success are the Life Skills Training curriculum and the Mid-
western Prevention Project. The Life Skills Training curriculum (Botvin et al., 1995a) is administered to seventh-grade students with booster sessions in the eighth and ninth grades. The curriculum was delivered in an interactive format by teachers who received training by videotape or personal training and technical assistance from the developers of the curriculum. Six-year follow-up results showed significant effects on use and heavy use of cigarettes and alcohol (although not on illicit drug use). There were minimal differences in effectiveness as a function of the type of teacher training. Although the findings apply only to white, middleclass students, the study is important for demonstrating long-term effectiveness, highlighting the potential importance of booster sessions, demonstrating the value of quality teacher training, and focusing on students who were exposed to 60 percent or more of the sessions (a so-called highfidelity sample).
The Midwestern Prevention Project (Pentz et al., 1989a,b) is another social influence prevention intervention that produced significant sixyear follow-up effects on the use of cigarettes, alcohol, marijuana, and cocaine for both high- and low-risk students. The primary vehicle for this intervention was a 10-session, school-based, social skills, and peer-resistance skills curriculum. However, the school intervention was supplemented by a parental involvement component, media campaigns, and training of community leaders. This suggests that a coordinated and comprehensive community-wide intervention may be more effective in producing long-term effects than a school-based program alone.
In summary, school-based, universal, primary prevention programs have been the dominant approach to preventing adolescent drug use in the past two decades. Research efforts have shown significant progress in developing, implementing, and evaluating the effects of school-based interventions. Most notably, recent social influence programs have empirically demonstrated short-term effectiveness; fairly consistent research results demonstrate that one can achieve 20 percent or greater net reductions in rates of initiation of drug use from school programs that focus on counteracting social influences to drug use; these include standardized teacher or staff training, multiple class sessions, booster sessions, student peer leaders, and active social learning methods (Pentz, 1994). However, there have been only a few studies showing long-term success of schoolbased and curriculum-driven prevention interventions.
Research on school-based prevention interventions has contributed important knowledge to the broader field of prevention science. For example, recent social influence programs have strengthened the integral relationship between etiology and prevention (Bandura, 1977a,b, 1985; Hawkins and Weis, 1985; Brook et al., 1992; Brunswick et al., 1992; Glantz and Pickens, 1992; Hawkins et al., 1992a; Cloninger et al., 1993, 1995; Flay
and Petraitis 1994a,b). Social influence programs have recognized the importance of constructing theory-based interventions designed to counteract known risk factors for drug use initiation and of identifying the mediating mechanisms through which interventions have their effects (MacKinnon et al., 1991). In this way, preventive interventions enhance basic etiological research, with school-based interventions providing important experimental tests of theories of adolescent drug use and problem behavior (Coie et al., 1993).
Prevention intervention research (led by recent school-based programs) has also stimulated important advances in methodology, including quantitative methods for evaluating program effectiveness. The drug abuse research field in general has been a productive seedbed for innovations in statistical techniques, such as structural equation modeling (Bentler, 1991), latent transition analysis (Collins et al., 1994), mechanisms for dealing with missing data (Graham et al., 1994), managing problems of attrition (Hansen et al., 1985, 1990; Biglan et al., 1991), hazard survival analysis (Yamaguchi, 1991), and measuring mediating mechanisms underlying intervention effects (MacKinnon et al., 1991). School-based prevention research is now benefiting from advances in the analysis of multilevel data, allowing for the study of children nested within classrooms and schools (Laird and Ware, 1982; Bryk and Raudenbusch, 1992; Gibbons and Hedeker, 1994; Hedeker et al., 1994). Important work has also been done in evaluating the validity of self-reported drug use as an outcome measure, including bioassays to detect smoking or alcohol consumption (Harrell, 1988; Rouse et al., 1988) and emergent technologies such as analysis of protein in hair samples.
Research on risk and protective factors associated with adolescent drug use and abuse provides several rationales for family-based prevention interventions. First, research suggests that parenting characterized by high levels of support, consistent rule enforcement, and monitoring of child behavior is associated with lower rates of drug use (Steinberg 1991; Hawkins et al., 1992a). Thus, interventions to improve parenting practices may lower the risk for adolescent drug use. Second, research suggests that parental drug abuse is a risk factor for drug abuse by offspring (Merikangas et al., 1992), and that disrupted parenting in these families may contribute to the risk (Mayes, 1995). If so, parenting interventions could help to reduce the risk for drug abuse among children of drugabusing parents. Third, research also shows that impaired parental monitoring, poor contingency management, and coercive discipline are associated with childhood aggression and conduct problems (Reid, 1993).
Because childhood conduct problems (delinquency, aggression, conduct disorder, or oppositional defiant disorder) are important risk factors for drug abuse, they may share common etiological pathways (see Oetting and Beauvais, 1987; Patterson et al., 1989; Gottfredson et al., 1991; Abikoff and Klein, 1992; Moffitt, 1993; Huizinga et al., 1994). Family-based interventions designed to prevent conduct disorder may therefore have important effects on drug abuse and dependence.
Parent education and family support interventions have successfully reduced parental stress, enhanced parental confidence, and reduced child abuse and neglect (Olds et al., 1986; Wolfson et al., 1992). Children whose parents have received these types of interventions exhibit fewer school attendance and academic problems (Seitz et al., 1991). However, family support interventions alone may be insufficient to produce lasting effects on antisocial behavior or drug use. A review of early intervention programs for delinquency prevention suggested that interventions for urban, low-income families that combined high-quality preschool environments with family support interventions, and were delivered for multiple years, had the highest rates of success (Yoshikawa, 1994).
Although parent training programs alone are insufficient to reduce drug abuse in children, parent training interventions that directly teach parents to monitor behavior, use appropriate contingency management, and reduce coercive discipline have been shown to reduce antisocial behavior in children (Kazdin, 1987). Parenting interventions alone are not developmentally appropriate after school entry because they do not influence important risk factors such as peer relationships and school achievement (Reid, 1993). For elementary school children, few controlled studies have examined the effects of interventions in school and family simultaneously. One study that combined modified teaching practices in mainstream classrooms and parent training (designed to be developmentally appropriate as students went from the first through the fourth grades) demonstrated significantly lower rates of alcohol initiation and delinquency initiation in students whose parents received training than in control students (Hawkins et al., 1992b).
Another study is currently evaluating a combination of parent training, home visits and family support, social skills training, anger management training, academic tutoring, and modifications in the classroom environment (Conduct Problems Prevention Research Group, 1992). This program includes both universal components (the school curriculum) and selective interventions (family and social skills components) for children screened in kindergarten who showed high levels of disruptive behaviors. These researchers suggest that effective intervention requires multiple years and that both entry into elementary school and the transition to middle school are particularly important times for intervention (Con-
duct Problems Prevention Research Group, 1992). Outcome data are not yet available, but other studies have found long-term reductions in adolescent drug use by using a multicomponent program including a schoolbased social influence intervention, family involvement, media intervention, and community organization (Pentz et al., 1989a,b).
Media-based interventions, particularly PSAs (public service announcements), are an interesting but understudied channel for drug abuse prevention. The appeal of using media (radio, TV, billboards, and print) is that this can be a relatively cost-effective way to reach a large audience; however, few studies have attempted to demonstrate the successes of media-based drug prevention. In the only widespread attempt to use television for antidrug programming, the Partnership for a Drug-Free America was very successful in obtaining both donated services for preparing antidrug PSAs and donated time to air for them.1 Unfortunately, rigorous examination of the effects of PSAs on actual drug use and abuse are not available, although they may have important effects on generating and sustaining drug-free norms.
A small number of empirically evaluated media interventions have been used to prevent adolescent cigarette smoking. One evaluation found significant main effects for both classroom training and television programming on knowledge and prevalence estimates, and significant impacts of classroom and television programming on knowledge, disapproval of parental smoking, and efforts at coping (Flay et al., 1995). However, sustained effects on smoking were not observed. An earlier evaluation found that adolescents who received both school-based prevention programs and (independently delivered) radio and TV antismoking messages showed significant reductions in smoking prevalence compared to those who received school-based intervention alone (Flynn et al., 1992). The earlier study is important in showing that a media component can significantly enhance the outcomes of a school-based campaign. Researchers estimated that after a concentrated antismoking campaign, sales of cigarettes in California were reduced by more than 1 billion packs from the third quarter of 1990 through the fourth quarter of 1992, and that approximately 20 percent of this reduction was attributable to the media campaign (the other 80 percent was attributed to a 25-cent increase in the
sales tax) (Hu et al., 1995). This shows the relative effectiveness of a policy change intervention in conjunction with a media intervention, and the most effective use of media may be in combination with other interventions.
Since the 1970s, preventive interventions have expanded their focus from the individual to the broader community. In part, this interest in community-wide interventions stems from the realization that it is difficult if not impossible to effect changes in individuals when there are countervailing forces in the larger social environment. For example, school-based interventions alone will be ineffective if they are delivered in a community in which drug use is widespread and normative (e.g., drugs are widely available, and no sanctions are applied against drug use). Typically, community interventions relating to drug use have been implemented in conjunction with political actions that focus on changing laws and policies concerning drug use. Policy goals include strict enforcement of regulations against use, reducing youth access, increasing the costs of legal drugs (e.g., through tobacco taxes), and changing community norms about drug use.
Although there has been substantial activity involving the delivery of community interventions for drug abuse prevention, few programs have been evaluated rigorously. In the field of adolescent smoking, Perry and colleagues (1992) demonstrated that a community intervention improved outcomes above and beyond those of a school-based intervention alone. Moreover, the Midwest Prevention Project (Pentz et al., 1989a), which included a community component, demonstrated long-term reductions in drug use prevalence (although the effects of the community component were not identified separately). Smith and Davis (1993) found that community prevention programs can be successful in poor neighborhoods with substantial technical assistance. Finally, several promising community interventions are currently under way to reduce adolescent alcohol consumption (Wagenaar and Perry, 1994). In general, however, there have been few empirically rigorous demonstrations of success, and the successes that have been recorded have been described as "meager" compared to the effort that has been expended (Susser, 1995).
Reasons for modest demonstrations of success can be found in the complexity of evaluating these community programs (Pirie et al., 1994). First, programs administered on a large scale cannot be as tightly organized as programs administered to small groups, making monitoring of implementation both necessary and challenging. Second, because multiple program components are occurring simultaneously, it is difficult to
assess the effects of any one component. Third, the recipients of the programs are located throughout the community and may be poorly identified, making evaluation and data collection complex and expensive. Fourth, most community programs do not occur in a vacuum, but rather coexist with national and local programs, making it difficult to disentangle the effects of the program under consideration from the background of similar programs.
In addition to methodological explanations for the weak effects, community interventions may also fail if the interventions are not sufficiently intense or if they are too brief to achieve enduring behavior change. A challenge for community trials is to sustain the efforts, transferring ownership to ongoing community groups after the research team has ended its involvement (Bracht et al., 1994). Ironically, the effects obtained by community interventions may also appear meager because they are eclipsed by the very same social movements that originally provided the impetus for the intervention (Susser, 1995). For example, the current national movement toward health consciousness may result in declines in drug use and abuse that render it difficult to produce or detect further change through controlled interventions.
At this time, the conclusion that is most appropriate is that community approaches to drug abuse prevention are intuitively appealing, but evidence of effectiveness is relatively weak. This is true because the amount and quality of existing research is limited, not because the evidence is broad based and inconclusive. Thus, rigorous and systematic research on community-based prevention interventions is needed.
GAPS AND NEEDS
Despite important advances in prevention science directly attributable to school-based interventions, many research needs and opportunities remain. Specifically, there is a need both for a better understanding of the role of booster sessions to sustain early gains and methods for improving the long-term maintenance of program effects. The committee has also identified six areas for future research on school-based interventions:
Tailoring interventions to high-risk subgroups within universal schoolbased interventions: To date, school-based prevention interventions have been "universal" (directed at the general adolescent population). It is important to learn how segmented groups of students (particularly those at high risk for drug use and abuse) are affected by particular interven-
tions. Subgroups of special interest include those with preexisting conduct problems, chronic absentees or truants, and those with poor academic achievement.
Etiologic research has documented the importance of these individual differences in predicting drug use and abuse (Chapter 5).
The effectiveness of culturally tailored interventions: In addition to subgroups that vary on known risk factors for drug use, little is known about tailoring preventive interventions to particular ethnic subgroups. One study found that a culturally tailored intervention produced improved outcomes over a generic skills program at two-year follow-up (Botvin et al., 1995b). However, there is a dearth of basic information to provide a rationale for culturally tailored interventions, and little is known about their efficacy.
Evaluating multichannel interventions: Efforts must be made to incorporate the effects of preventive interventions from other channels into analyses of school-based programs. Recent research suggests that prevention effectiveness is improved by combining school-based programs with family, peer, community, and media interventions (Pentz et al., 1989a,b,c; Botvin, 1990; Hansen et al., 1990; Johnson et al., 1990; Tobler, 1992). Additional research is needed on the outcome effects of the multiple components of comprehensive interventions.
Preventing the transition from drug use to abuse and dependence: Most school-based programs focus on the prevention of drug use, but research is also needed on effective ways to prevent transitions from drug use to abuse and dependence. This research should identify modifiable risk and protective factors associated with the transition to drug abuse, so that intervention programs can be designed to influence these factors. At the present time, some risk factors have been identified, but many are not easily modifiable through school-based intervention (e.g., parental drug abuse and antisocial behavior, family history of psychopathology and disruption, childhood conduct problems, aggression, difficulties in regulating emotional arousal, sensation seeking, impulsivity, poor school achievement, and difficulties in coping [Glantz and Pickens, 1992]). The extent to which school-based programs can modify these risk factors and influence high-risk youth is an important area for future research. Additionally, school-based programs are targeted primarily at elementary and middle school children, who may or may not be at the stage of onset of drug use, whereas there are fewer prevention interventions targeted at adolescents and young adults, who are in the peak stages of drug use and abuse.
Diffusion as a focus of research: For the few interventions that have demonstrated enduring success, research on the process of dissemination is warranted. Although some research does exist on the fidelity of pro-
grams that are transferred from controlled research protocols to the community, the evidence is insufficient to justify conclusions at this time. Further, the actual impact of programs that have been transported from researcher to practitioner has not been systematically studied (Botvin, 1990; Butterfoss et al., 1993; Jackson et al., 1994; Leupker, 1994; Pirie et al., 1994). Therefore, research on the diffusion process by which programs are marketed, received, adopted, and transferred from researchers to practitioners, and on the effectiveness of such ''transferred" programs, is another area for further study.
Cost-benefit considerations in preventive intervention: Continued research is needed on the public health impact and cost-effectiveness of school-based prevention programs. Pentz (1994) estimated that for every $1 spent on the Midwestern Prevention Project, $8 in treatment costs was saved for teenagers and $67 in treatment costs for adults. Botvin and colleagues (1995a) estimated the number of potential lives that would be saved from net reductions in cigarette smoking among those who received the Life Skills Training program. These early attempts at cost-benefit and cost-effectiveness analysis would be enhanced by substantially more conceptual clarity and measurement rigor. An assessment of the benefits and cost-effectiveness of school-based prevention interventions should be considered an integral part of program evaluations.
In general, family-based interventions show promise as prevention strategies because they impact known risk and protective factors associated with adolescent drug use and abuse and because they impact important mediating variables (such as childhood conduct problems) that are known risk factors for later drug abuse and dependence. At the present time, however, there have been too few studies specifically focused on drug use and abuse as outcomes to draw definitive conclusions. Moreover, studies that have evaluated the prevention and treatment of antisocial behavior and delinquency suggest that family interventions alone are inadequate; social skills training, academic tutoring, high-quality school environments, and family support services may be required for significant and sustained outcomes.
These multicomponent programs, although theoretically promising in influencing known risk factors for drug abuse, have important limitations. First, outcome studies have not focused on drug use and abuse, so the efficacy of these programs in preventing drug abuse is unknown. Second, they face challenges to implementation, including the need to actively recruit and retain high-risk families (Conduct Problems Prevention Research Group, 1992). Third, selective interventions focused on high-
risk children must include screening methods that minimize false positives and false negatives and also minimize the risk of negative labeling effects. For example, recent data on early elementary school children show high false-positive rates (up to 30 percent) in screening for risk of conduct problems (Lochman and the Conduct Problems Prevention Research Group, 1995). Fourth, recent data raise the possibility of iatrogenic effects produced by selective interventions that concentrate groups of antisocial adolescents in peer group interventions; such a strategy may inadvertently increase adolescent problem behavior (Dishion and Andrews, 1995).
Thus, despite substantial progress in the development, implementation, and evaluation of family-based prevention interventions, there are continuing needs and opportunities for research in the following areas:
Family interventions for high-risk groups: Research is needed on effective family interventions for groups at high risk for drug abuse, including children with conduct problems and children of drug-abusing parents. These are not necessarily independent subgroups; children of drug-abusing parents may be at risk for drug abuse partially because of their conduct problems. Because many of these programs target early elementary school children, longitudinal follow-up is necessary to assess relevant drug use outcomes, although short-term impacts on risk mediators (e.g., problem conduct) might be seen even in the elementary school years. Additionally, greater integration of preventive interventions focused on drug use or abuse, conduct disorders, and delinquency is needed (IOM, 1994b).
Current methods for defining and assessing high-risk groups produce high rates of false positives. It is necessary, therefore, to develop reliable and valid screening and assessment instruments, as well as methods of intervention delivery, designed to minimize the likelihood of negative labeling effects for selective interventions. This might be accomplished by incorporating interventions within existing treatment programs for drug-abusing parents, within existing prevention and treatment services for children with conduct problems, or within existing treatment and prevention programs in the juvenile justice system. In these ways, children would not be further labeled.
Developmentally appropriate interventions: At early ages, high-quality preschool environments and social skills training may be important additions to family-based interventions. At later (adolescent) ages, interventions may also benefit from focusing on communication skills and family management of external stress (Tolan et al., 1995). However, concentrating antisocial adolescents in peer group interventions may have negative effects (Dishion and Andrews, 1995).
Media interventions are appealing because of their potential to reach a large audience in a cost-effective manner, but few studies have evaluated the utility of media campaigns in preventing drug abuse. Moreover, the challenges of implementing a media intervention include achieving sufficient intensity so that individuals are actually exposed to the message; targeting high-risk subgroups; tailoring messages to the needs and values of those groups; creating messages that are compelling enough to engage the viewer and be remembered; and preventing unintended negative consequences (e.g., inadvertently creating the impression that drug use is widespread and normative; U.S. DHHS, 1994). For legal drugs, media messages must also be powerful enough to counter intensive advertising campaigns. Finally, a media campaign alone is unlikely to be sufficient for prevention and should be combined with school-based or community policy interventions for maximum benefit (Pentz et al., 1989a,b; Flynn et al., 1992). Because there has been little research on the effectiveness of media interventions in the prevention of drug abuse, this area may warrant future research.
Research on the efficacy of policy-oriented community interventions must overcome several major challenges. A guiding principle of prevention research is that the intervention must effectively manipulate the mediating variables in order to produce change in a desired direction. Unfortunately, mediating variables at the community level are not yet well understood. There is a need for theory-based community interventions in which the theory of change addresses community-level mediating mechanisms in interaction with individual-level risk factors (Holder, 1994). Another challenge for community-based research is to develop effective methods for achieving the desired policy changes (above and beyond the question of whether policy changes actually produce the desired reductions in drug use, abuse, and dependence). Most community interventions involve coalition development, community organization, and a mobilization of community leaders. However, to date the literature on building and maintaining such coalitions can be characterized as "wisdom literature," because it is largely anecdotal and tends to be based on experiences and impressions (Butterfoss et al., 1993).
From both a practical and a research perspective, prevention interventions are a core feature of the nation's attempts to reduce the demand for alcohol, tobacco, and illicit drugs among people of all ages and in all settings. As a result of prevention intervention research, however, many intuitively appealing strategies for reducing the demand for alcohol, tobacco, or illicit drugs, particularly among young people, have been found inadequate or even irrelevant. A "magic bullet" is no more likely to be found in prevention than in treatment or drug control. Instead, all modes of intervention must be pursued concurrently in order to maximize their contributions to the overall effort. For this reason, adequate evaluation research should be regarded as an essential feature of any preventive intervention. The committee has identified future research needs within each major area of prevention research, but many of its suggestions and recommendations for future research directions converge on several priorities for the field as a whole, including the following areas:
Prevention intervention research should focus more attention on the transition from use to abuse and dependence. To date, most prevention research has focused on preventing initiation of drug use. Without neglecting initiation, more research is needed on determinants of the transition from drug use to abuse and dependence and on the ways that preventive interventions can influence that transition. This need includes further research on measuring risk for drug abuse and dependence and whether risk measurement is appropriately sensitive and specific to support selective interventions. Within universal prevention programs, there is a need to study program impact on subgroups of subjects at high risk for drug abuse and dependence.
Prevention research should be diversified to target populations other than young adolescents. Until now, drug abuse prevention research has focused on the transition to adolescence because this is the time of drug use initiation. However, prevention research has been relatively neglected at other key points in the life span. Prevention research is needed in the preschool and elementary school years, targeted on preexisting risk factors for drug abuse-particularly the development of conduct problems. Prevention research is also needed during the transition to young adulthood, when drug abuse and dependence disorders are at peak levels. Possible settings for these interventions include colleges, work sites, the military, and settings where school dropouts (high school and college) congregate (Pentz, 1994). Finally, little is known about preventing drug abuse problems in later adulthood (Burton et al., in press).
Prevention research should be diversified to reach minority populations.
Until recently, most prevention research and evaluations of preventive interventions have been limited to white, middle-class populations. Little is known about the effectiveness of prevention interventions on populations segmented on race, ethnicity, and socioeconomic status. Etiological and prevention research should be expanded to reach diverse populations. An important question that requires attention concerns the degree to which preventive intervention programs need to be "culturally specific" in order to be maximally effective.
Prevention research should focus on the design and evaluation of multicomponent interventions, especially at the community level. As noted above, multicomponent interventions show promise for preventing drug use as well as the conduct problems that increase the risk for drug abuse, but more research is needed on the interactions among these components, especially in community-level interventions. Particular attention should be paid to the ways in which various modes of legal intervention can be integrated with traditional modes of prevention. Very little research has been conducted on the relative and synergistic effects of simultaneous supply reduction and demand reduction strategies (Pentz, 1994; Clayton, 1995). As noted in Chapter 10, integrated interventions in drug law enforcement and other community-level channels represent an intriguing opportunity for innovative research.
Additionally, greater attention should be paid to the development and application of models for assessing the benefits and cost-effectiveness of various prevention intervention approaches to drug use, abuse, and dependence. To do so requires an understanding of how to define and measure the units of prevention delivered and received and how to attribute to those exposure units specific outcomes that can also be measured and assigned a value (Plotnick, 1994).
Finally, federal funding agencies should facilitate interagency collaboration and coordination of prevention research. As is evident from the literature on etiology and prevention intervention, drug use prevention is integrally tied to prevention of problems and conditions lying within the province of multiple federal agencies including the National Institute on Drug Abuse (prevention research on drug abuse); the National Institute of Mental Health (prevention research on disorders that precede or are co-occurring with drug abuse); the National Institute on Alcohol Abuse and Alcoholism (prevention research on alcohol abuse and dependence); both the National Cancer Institute and the National Heart, Lung, and Blood Institute (prevention research on nicotine dependence); and the National Institute of Justice (research on the relationship of drug abuse to criminality). For the field of drug prevention science,
procedures and structures should be developed to facilitate interagency collaboration and coordination of prevention research (Chapter 1).
The committee recommends rigorous evaluation of universal versus targeted prevention intervention programs with regard to effectiveness and cost-effectiveness, with particular focus on the initiation of use and on the transition from use to abuse and dependence. Emphasis should be placed on school-, family-, media-, and community-based interventions; interventions appropriate for high-risk populations; interventions aimed at ethnic subgroups; and multicomponent interventions especially at the community level.
Abikoff H, Klein R. 1992. Attention-deficit hyperactivity and conduct disorder: Comorbidity and implications for treatment. Journal of Consulting and Clinical Psychology 60:881-892.
Bandura A. 1977a. Social Learning Theory. Englewood Cliffs, NJ: Prentice-Hall.
Bandura A. 1977b. Self-efficacy: Toward a unifying theory of behavioral change. Psychological Review 84:191-215.
Bandura A. 1985. Social Foundations of Thought and Action. Englewood Cliffs, NJ: Prentice-Hall.
Bentler PM. 1991. Modeling of intervention effects. In: Leukefeld CG, Bukoski WJ, eds. Drug Abuse Prevention Intervention Research: Methodological Issues. Rockville, MD: NIDA. Pp. 159-182.
Biglan A, Hood D, Brozovsky P, Ochs L, Ary D, Black C. 1991. Subject attrition in prevention research. NIDA Research Monograph 107:213-234.
Botvin GJ. 1990. Substance abuse prevention: Theory, practice, and effectiveness. In: Tonry M, Wilson JQ, eds. Crime and Justice: A Review of Research, Vol. 13. Chicago: University of Chicago Press. Pp. 461-519.
Botvin GJ, Baker E, Dusenbury L, Botvin EM, Diaz T. 1995a. Long-term follow-up results of a randomized drug abuse prevention trial in a white middle-class population. Journal of the American Medical Association 273:1106-1112.
Botvin GJ, Schinke SP, Epstein JA, Diaz T, Botvin EM. 1995b. Effectiveness of culturally focused and generic skills training approaches to alcohol and drug abuse prevention among minority adolescents: Two year follow-up results. Psychology of Addictive Behaviors 9:183-194.
Bracht N, Finnegan JR, Rissel C, Weisbrod R, Gleason J, Corbett J, Veblen-Mortenson S. 1994. Community ownership and program continuation following a health demonstration project. Health Education Research 9:243-255.
Brook JS, Cohen P, Whiteman M, Gordon AS. 1992. Psychosocial risk factors in the transition from moderate to heavy use or abuse of drugs. In: Glantz MD, Pickins RW, eds. Vulnerability to Drug Abuse. Washington, DC: American Psychological Association Press. Pp. 359-388.
Brunswick AF, Messeri PA, Titus SP. 1992. Predictive factors in adult substance abuse: A prospective study of African American adolescents. In: Glantz MD, Pickins RW, eds. Vulnerability to Drug Abuse. Washington, DC: American Psychological Association Press. Pp. 419-472.
Bryk A, Raudenbusch S. 1992. Hierarchical Linear Models: Applications and Data Analysis Methods. Newbury Park, CA: Sage.
Burton R, Johnson R, Ritter CJ, Clayton RR. In press. The effects of role socialization on the initiation of cocaine use: An event history analysis from adolescence into middle adulthood. Journal of Health and Social Behavior 37.
Butterfoss FD, Goodman RM, Wandersman A. 1993. Community coalitions for prevention and health promotion. Health Education Research 8:315-330.
Clayton R. 1995. Marijuana in a Challenging Third-World Region: Appalachia USA. Denver: Lynne Reinner.
Clayton R, Ann Arbor Group. 1994. Increase in Use of Selected Drugs: Monitoring the Future Study of 8th, 10th, and 12th Graders. Ann Arbor, MI: University of Michigan. Report for the Office of National Drug Control Policy.
Cloninger R, Svrakic D, Przybeck T. 1993. A psychobiological model of temperament and character. Archives of General Psychiatry 50:975-990.
Cloninger R, Przybeck T, Svrakic D, Wetzel R. 1995. The Temperament and Character Inventory: A Guide to Its Development and Use. St. Louis, MO: Center for Psychobiology of Personality.
Coie JD, Norman FW, West SG, Hawkins JD, Asarnow JR, Markman HJ, Ramey SL, Shure MB, Long B. 1993. The science of prevention: A conceptual framework and some directions for a national research program. American Psychologist 48:1013-1022.
Collins LM, Graham JW, Rousculp SS, Fidler PL, Pan J, Hansen WB. 1994. Latent transition analysis and how it can address prevention research questions. NIDA Research Monograph 142:81-111.
Conduct Problems Prevention Research Group. 1992. A developmental and clinical model for the prevention of conduct disorders: The FAST Track program. Development and Psychopathology 4:509-527.
Dielman TE, Kloska D, Leech S, Schulenberg J, Shope JT. 1992. Susceptibility to peer pressure as an explanatory variable for the differential effectiveness of an elementary school-based alcohol misuse prevention program. Journal of School Health 62:233-237.
Dishion TJ, Andrews DW. 1995. Preventing escalation in problem behaviors with high-risk young adolescents: Immediate and 1-year outcomes. Journal of Consulting and Clinical Psychology 63:538-548.
Ellickson PL, Bell RM. 1990. Drug prevention in junior high: A multi-site longitudinal test. Science 247:1299-1305.
Ellickson PL, Bell RM. 1992. Challenges to social experiments: A drug prevention example. Journal of Research on Crime and Delinquency 29:79-101.
Ellickson PL, Bell RM, McGuigan K. 1993. Preventing adolescent drug use: Long-term results of a junior high program. American Journal of Public Health 83:856-861.
Ennett ST, Rosenbaum DP, Flewelling RL, Bieler GS, Ringwalt CR, Bailey SL. 1994a. Longterm evaluation of Drug Abuse Resistance Education. Addictive Behaviors 19:113-125.
Ennett ST, Tobler NS, Ringwalt CL, Flewelling RL. 1994b. How effective is Drug Abuse Resistance Education? A meta-analysis of project DARE outcome evaluations. American Journal of Public Health 84(9):1394-1401.
Flay B, Petraitis J. 1994a. The theory of triadic influence: A new theory of health behavior with implications for preventive interventions. Advances in Medical Sociology 4:19-44.
Flay B, Petraitis J. 1994b. A Review of Theory and Prospective Research on the Causes of Adolescent Tobacco Use. Paper prepared for the Robert Wood Johnson Foundation.
Flay BR, Miller TQ, Hedeker D, Siddiqui O, Britton CF, Brannon BR, Johnson CA, Hansen WB, Sussman S, Dent C. 1995. The Television, School, and Family Smoking Prevention and Cessation Project VIII: Student outcomes and mediating variables. Preventive Medicine 24:29-40.
Flynn BS, Worden JK, Secker-Walker RH, Badger GJ, Geller BM, Costanza MC. 1992. Prevention of cigarette smoking through mass media intervention and school programs. American Journal of Public Health 82:827-834.
Gibbons RD, Hedeker D. 1994. Application of random-effects probit regression models. Journal of Consulting and Clinical Psychology 62:285-296.
Glantz MD, Pickins RW. 1992. Vulnerability to drug abuse: Introduction and overview. In: Glantz MD, Pickins RW, eds. Vulnerability to Drug Abuse. Washington, DC: American Psychological Association Press. Pp. 1-14.
Gordon R. 1983. An operational classification of disease prevention. Public Health Reports 98:107-109.
Gottfredson D, McNeill R, Gottfredson G. 1991. Social area influences on delinquency: A multilevel analysis. Journal of Research in Crime and Delinquency 28:197-226.
Graham JW, Hofer SM, Piccinin AM. 1994. Analysis with missing data in drug prevention research. NIDA Research Monograph 142:13-63.
Hansen WB. 1992. School-based substance abuse prevention: A review of the state of the art in curriculum, 1980-1990. Health Education Research 7:403-430.
Hansen WB, Graham JW. 1991. Preventing alcohol, marijuana, and cigarette use among adolescents: Peer pressure resistance training versus establishing conservative norms. Preventive Medicine 20:414-430.
Hansen WB, Collins LM, Malotte CK, Johnson CA, Fielding JE. 1985. Attrition in prevention research. Journal of Behavioral Medicine 8:261-271.
Hansen WB, Tobler NS, Graham JW. 1990. Attrition in substance abuse prevention research: A meta-analysis of 85 longitudinally followed cohorts. Evaluation Review 14:677-685.
Harrell AV. 1988. Validation of self-report: The research record. NIDA Research Monograph 57:12-21.
Hawkins JD, Weis J. 1985. The social development model: An integrated approach to delinquency prevention. Journal of Primary Prevention 6:73-97.
Hawkins JD, Catalano RF, Miller JY. 1992a. Risk and protective factors for alcohol and other drug problems in adolescence and early adulthood: Implications for substance abuse prevention. Psychological Bulletin 112:64-105.
Hawkins JD, Catalano RF, Morrison DM, O'Donnell J, Abbott RD, Day LE. 1992b. The Seattle Social Development Project: Effects of the first four years on protective factors and problem behaviors. In: McCord J, Tremblay R, eds. The Prevention of Antisocial Behavior in Children. New York: Guilford.
Hedeker D, Gibbons RD, Flay BR. 1994. Random-effects regression models for clustered data with an example from smoking prevention research. Journal of Consulting and Clinical Psychology 62:757-765.
Holder HD. 1994. Commentary, Alcohol availability and accessibility as part of the puzzle: Thoughts on alcohol problems and young people. In: Zucker R, Boyd G, Howard J, eds. The Development of Alcohol Problems: Exploring the Biopsychosocial Matrix of Risk. Pp. 249-254. NIAAA Research Monograph 26. Rockville, MD: U.S. DHHS.
Hu TW, Sung HY, Keeler TE. 1995. Reducing cigarette consumption in California: Tobacco taxes vs. an anti-smoking media campaign. American Journal of Public Health 85(9):1218-1222.
Huizinga D, Loeber R, Thornberry T. 1994. Urban Delinquency and Substance Abuse: Initial Findings. Washington, DC: Office of Juvenile Justice and Delinquency Prevention, Department of Justice.
IOM (Institute of Medicine). 1994a. Growing Up Tobacco Free: Preventing Nicotine Addiction in Children and Youths. Washington, DC: National Academy of Sciences.
IOM (Institute of Medicine). 1994b. Reducing Risks for Mental Disorders: Frontiers for Preventive Intervention Research. Washington, DC: National Academy Press.
Jackson C, Fortmann SP, Flora JA, Melton RJ, Snkider JP, Littlefield D. 1994. The capacity building approach to intervention maintenance implemented by the Stanford Five City Project. Health Education Research 9:385-396.
Johnson C, Pentz M, Weber M, Dwyer J, Baer N, MacKinnon D, Hansen W, Flay B. 1990. Relative effectiveness of comprehensive community programming for drug abuse prevention with high-risk and low-risk adolescents. Journal of Consulting and Clinical Psychology 58:447-456.
Kazdin A. 1987. Treatment of antisocial behavior in children: Current status and future directions. Psychological Bulletin 102:187-203.
Laird NM, Ware JH. 1982. Random effects models for longitudinal data. Biometrics 38:963-974.
Leupker RV. 1994. Community trials. Preventive Medicine 23:602-605.
Lochman JE, Conduct Problems Prevention Research Group. 1995. Screening of child behavior problems for prevention programs at school entry. Journal of Consulting and Clinical Psychology 63:549-559.
MacKinnon DP, Johnson CA, Pentz MA, Dwyer JH, Hansen WB, Flay BR, Wang E. 1991. Mediating mechanisms in a school-based drug prevention program: First year effects of the Midwestern Prevention Project. Health Psychology 10:164-172.
Mayes LC. 1995. Substance abuse and parenting. In: Bornstein MH, ed. Handbook of Parenting, Vol. 4. Applied and Practical Parenting. Mahway, NJ: Lawrence Erlbaum Publishers. Pp. 101-125.
Merikangas KR, Rounsaville BJ, Prusoff BA. 1992. Familial factors in vulnerability to substance abuse. In: Glantz MD, Pickins RW, eds. Vulnerability to Drug Abuse. Washington, DC: American Psychological Association Press. Pp. 75-98.
Moffitt TE. 1993. Adolescence-limited and life-course-persistent antisocial behavior: A developmental taxonomy. Psychological Review 100:674-701.
Murray DM, Pirie P, Luepker RV, Pallonen U. 1989. Five- and six-year follow-up results from four seventh-grade smoking prevention strategies. Journal of Behavioral Medicine 12:207-218.
Oetting ER, Beauvais F. 1987. Peer cluster theory, socialization characteristics, and adolescent drug use: A path analysis. Journal of Consulting Psychology 34:205-213.
Olds DL, Henderson CR, Chamberlin R, Tatelbaum R. 1986. Preventing child abuse and neglect: A randomized trial of nurse home visitation. Pediatrics 78:65-78.
Patterson G, DeBaryshe B, Ramsey E. 1989. A developmental perspective on antisocial behavior. American Psychologist 27:329-335.
Pentz MA. 1994. Directions for future research in drug abuse prevention. Preventive Medicine 23:646-652.
Pentz MA, MacKinnon D, Flay B, Hansen W, Johnson CA, Dwyer J. 1989a. Primary prevention of chronic diseases in adolescence: Effects of the Midwestern Prevention Project on tobacco use. American Journal of Epidemiology 130:713-724.
Pentz MA, Dwyer J, MacKinnon D, Flay BR, Hansen WB, Wang EY, Johnson CA. 1989b. A multicommunity trial for primary prevention of adolescent drug abuse. Journal of the American Medical Association 261:3259-3266.
Pentz MA, MacKinnon DP, Dwyer JH, Wang EYI, Hansen WB, Flay BR, Johnson CA. 1989c. Longitudinal effects of the Midwestern Prevention Project on regular experimental smoking in adolescents. Preventive Medicine 18:304-321.
Perry CL, Kelder SH, Murray DM, Kepp K-I. 1992. Community-wide smoking prevention: Long-term outcomes of the Minnesota Heart Health Program and the Class of 1989 Study. American Journal of Public Health 82:1210-1216.
Pirie PL, Stone EJ, Assaf AR, Flora JA, Maschewsky-Schneider U. 1994. Program evaluation strategies for community-based health promotion programs: Perspectives from the cardiovascular disease community research and demonstration studies. Health Education Research 9:23-36.
Plotnick RD. 1994. Applying benefit-cost analysis to substance use prevention programs. International Journal of the Addictions 29:339-359.
Reid JB. 1993. Prevention of conduct disorder before and after school entry: Relating interventions to developmental findings. Development and Psychopathology 5:243-262.
Resnicow K, Botvin G. 1993. School-based substance use prevention programs: Why do effects decay? Preventive Medicine 22:484-490.
Ringwalt C, Greene J, Ennett S, Iachan R, Clayton R, Leukefeld C. 1994. Past and Future Directions of the D.A.R.E. Program: An Evaluation Review. Final Report to the National Institute of Justice.
Rouse BA, Kozel NJ, Richards LG. 1988. Self-Report Methods of Estimating Drug Use: Meeting Current Challenges to Validity. Rockville, MD: NIDA.
Seitz V, Apfel NH, Rosenbaum LK. 1991. Effects of an intervention program for pregnant adolescents: Educational outcomes at two years postpartum. American Journal of Community Psychology 19:911-931.
Smith BE, Davis RC. 1993. Successful community anti-crime programs: What makes them work? In: Davis RC, Lurigio AJ, Rosenbaum DP, eds. Drugs and the Community: Involving Community Residents in Combatting the Sale of Illegal Drugs. Springfield, IL: Charles C Thomas. Pp. 123-137.
Steinberg L. 1991. Autonomy, conflict, and harmony in the family relationship. In: Feldman SS, Elliott GR, eds. At the Threshold: The Developing Adolescent. Cambridge, MA: Harvard University Press. Pp. 255-276.
Susser M. 1995. The tribulations of trials-intervention in communities. American Journal of Public Health 85:156-158.
Tobler NS. 1992. Drug prevention programs can work: Research findings. Journal of Addictive Diseases 11:1-28.
Tolan P, Guerra NG, Kendall PC. 1995. A developmental-ecological perspective on antisocial behavior in children and adolescents: Towards a unified risk and intervention framework. Journal of Consulting and Clinical Psychology 63:579-584.
U.S. DHHS (U.S. Department of Health and Human Services). 1994. Preventing Tobacco Use Among Young People: A Report of the Surgeon General. Atlanta, GA: U.S. DHHS, Public Health Service, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health.
Wagenaar AC, Perry CL. 1994. Community strategies for the reduction of youth drinking: Theory and application. Journal of Research on Adolescence 4:319-345.
Wolfson A, Lacks P, Futterman A. 1992. Effects of parent training on infant sleeping patterns, parents' stress, and perceived parental competence. Journal of Consulting and Clinical Psychology 60:41-49.
Yamaguchi K. 1991. Event History Analysis. Newbury Park, CA: Sage.
Yoshikawa H. 1994. Prevention as cumulative protection: Effects of early family support and education on chronic delinquency and its risks. Psychological Bulletin 115:28-54.