Group versus individual format of intervention for aggressive children: Moderators and predictors of outcomes through 4 years after intervention.

This study originated in collaboration with Thomas Dishion because of concerns that a group format for aggressive children might dampen the effects of cognitive-behavioral intervention. Three hundred sixty aggressive preadolescent children were screened through teacher and parent ratings. Schools were randomized to receive either an individual or a group format of the child component of the same evidence-based program. The results indicate that there is variability in how group-based cognitive-behavioral intervention can affect aggressive children through a long 4-year follow-up after the end of the intervention. Aggressive children who have higher skin conductance reactivity (potentially an indicator of poorer emotion regulation) and who have a variant of the oxytocin receptor gene that may be associated with being hyperinvolved in social bonding have better outcomes in their teacher-rated externalizing behavior outcomes over time if they were seen individually rather than in groups. Analyses also indicated that higher levels of the group leaders' clinical skills predicted reduced externalizing behavior problems. Implications for group versus individual format of cognitive-behavioral interventions for aggressive children, and for intensive training for group therapists, informed by these results, are discussed.

Cognitive Behavioral Intervention for Youth at Risk for Conduct Problems: Future Directions.

This article briefly overviews the history of cognitive behavioral intervention (CBI) for children displaying early signs, or actual diagnoses, of conduct disorders. A series of randomized control trials have identified evidence-based CBI programs for children with these behavior problems at various developmental stages from preschool through adolescence. Although it is critically important for the field to disseminate these existing programs as developed, we argue that it is important to also move beyond the existing evidence-based programs. Research should continue to test new comprehensive, multicomponent interventions, fueled by our evolving understanding of active mechanisms that contribute to children's externalizing behavior problems. The future of research in this area can also benefit from a focus on four central issues. First, research can address how single interventions can have meaningful impact on a range of transdiagnostic outcomes because the intervention mechanisms may affect those various outcomes. Second, rooted in implementation science, we are beginning to understand better how evidence-based programs can be disseminated in the real world, examining key issues such as the adequacy of training approaches and the role of therapist and organizational characteristics. Third, a major focus of research can be on how to optimize intervention outcomes, including a focus on microtrials, on tailoring of interventions, on examining rigorously how interventions are delivered, and on the integration of technology and of other approaches such as mindfulness training into CBI. Fourth, research can explore how the therapeutic relationship and the therapists' characteristics can play substantial roles in effective CBI with conduct problem children.

Toward Tailored Interventions: Sympathetic and Parasympathetic Functioning Predicts Responses to an Intervention for Conduct Problems Delivered in Two Formats.

Coping Power is an evidence-based preventive intervention for youth with aggressive behavior problems that has traditionally been delivered in small group formats, but because of concerns about potentially diminished effects secondary to aggregation of high-risk youth, an individual format of Coping Power has been developed. The current study examined whether physiological characteristics of the child may provide information about which intervention delivery format works best for that individual. Indicators of sympathetic and parasympathetic nervous system functioning were examined in 360 fourth-grade children (65% male; 76.4% self-reported African-American) who were randomly assigned to Group Coping Power (GCP) or Individual Coping Power (ICP) (Lochman et al. 2015). Longitudinal assessments of teacher- and parent-reported proactive and reactive aggression were collected through a 1-year follow-up. For children with higher initial levels of aggression, those with lower parasympathetic functioning at pre-intervention showed greater reductions in teacher-rated proactive aggression in the ICP condition than the GCP condition. For children with high parasympathetic functioning, there was no differential effect of intervention format. Regardless of intervention format, youth with lower levels of sympathetic functioning at pre-intervention demonstrated greater reductions in teacher-rated proactive aggression. These findings suggest that physiological indicators may be worth considering in future studies examining which youth respond best to specific types of interventions.

Oxytocin Receptor Gene Variant Interacts with Intervention Delivery Format in Predicting Intervention Outcomes for Youth with Conduct Problems.

Coping Power is an evidence-based preventive intervention program for youth with aggressive behavior problems that has traditionally been delivered in small group formats. Because of concerns about iatrogenic effects secondary to aggregation of high risk youth, the current study examined whether genetic risk may moderate intervention outcome when youth were randomly assigned to group versus individual formats of an intervention. The oxytocin receptor gene (OXTR) has been associated with social behavior and may influence susceptibility to social reinforcement in general and deviant peer influence in particular. One variant of OXTR (rs2268493) was examined in 197 fourth-grade African-American children (64% male) who were randomly assigned to Group Coping Power or Individual Coping Power (Lochman et al. 2015). Longitudinal assessments of teacher- and parent-reported behavior were collected through a 1-year follow-up. Growth curve analyses revealed a genotype by delivery format interaction. Youth with the A/A genotype demonstrated reductions in externalizing problems over the course of the intervention regardless of intervention format. In contrast, carriers of the G allele receiving the group-based intervention showed little improvement during the intervention and a worsening of symptoms during the follow-up year, while those receiving the individual format demonstrated reductions in externalizing problems. Given the associations between this OXTR variant and social bonding, carriers of the G allele may be more sensitive to social rewards from deviant peers in the group setting. This study suggests that genetic factors may be useful in predicting which type of intervention will be most effective for a particular individual.

Pre-Post Tornado Effects on Aggressive Children's Psychological and Behavioral Adjustment Through One-Year Postdisaster.

Using a risk-resilience framework, this study examined how varying levels of exposure to a natural disaster (EF-4 tornado) and children's characteristics (sex; anxiety) influenced the behavioral and psychological adjustment of children who shared a common risk factor predisaster (elevated aggression) prior to exposure through 1-year postdisaster. Participants included 360 children in Grades 4-6 (65% male; 78% African American) and their parents from predominantly low-income households who were already participating in a longitudinal study of indicated prevention effects for externalizing outcomes when the tornado occurred in 2011. Fourth-grade children who were screened for overt aggressive behavior were recruited in 3 annual cohorts (120 per year, beginning in 2009). Parent-rated aggression and internalizing problems were assessed prior to the tornado (Wave 1), within a half-year after the tornado (Wave 2), and at a 1-year follow-up (Wave 3). Children and parents rated their exposure to aspects of tornado-related traumatic experiences at Wave 3. Children displayed less reduction on aggression and internalizing problems if the children had experienced distress after the tornado or fears for their life, in combination with their pre-tornado level of anxiety. Higher levels of children's and parents' exposure to the tornado interacted with children's lower baseline child anxiety to predict less reduction in aggression and internalizing problems 1 year after the tornado. Higher levels of disaster exposure negatively affected at-risk children's level of improvement in aggression and internalizing problems, when life threat (parent- and child-reported) and child-reported distress after the tornado were moderated by baseline anxiety.

Counselor-Level Predictors of Sustained Use of an Indicated Preventive Intervention for Aggressive Children.

Despite widespread concern about the frequent failure of trained prevention staff to continue to use evidence-based programs following periods of intensive training, little research has addressed the characteristics and experiences of counselors that might predict their sustained use of a program. The current study follows a sample of school counselors who were trained to use an indicated preventive intervention, the Coping Power program, in an earlier dissemination study, and determines their levels of continued use of the program's child and parent components in the 2 years following the counselors' intensive training in the program. Counselor characteristics and experiences were also examined as predictors of their sustained use of the program components. The Coping Power program addresses children's emotional regulation, social cognitive processes, and increases in positive interpersonal behaviors with at-risk children who have been screened to have moderate to high levels of aggressive behavior. The results indicated that counselors' perceptions of interpersonal support from teachers within their schools, their perceptions of the effectiveness of the program, and their expectations for using the program were all predictive of program use over the following 2 years. In addition, certain counselor personality characteristics (i.e., conscientiousness) and the level of actual teacher-rated behavior change experienced by the children they worked with during training were predictors of counselors' use of the program during the second year after training. These results indicate the central importance of teacher support and of child progress during training in the prediction of counselors' sustained use of a prevention program.

Intervention format and therapist-child agreement associated with therapeutic alliance and outcomes.

OBJECTIVE: The study examined the effects of therapeutic alliance (TA; relational bond, task collaboration) on externalizing behavior outcomes, how TA can operate differently when children are seen in individual versus group sessions, and how therapist-child disagreement in perceptions of TA affects outcomes. METHOD: Three hundred sixty children (Ages 9.2-11.8; 65% male; 78.1% Black) identified as having high rates of aggressive behavior by the fourth-grade teachers, and their 20 elementary schools were randomized to group versus individual delivery of the cognitive behavioral intervention, Coping Power. TA ratings were collected from children and therapists at mid and end of intervention using the Therapeutic Alliance Scale for Children. Teacher ratings of children's externalizing and internalizing behavior problems were collected prior to intervention and at 1-year follow-up after intervention using the Behavior Assessment System for Children. RESULTS: Children receiving the intervention individually reported significantly higher trait-like levels of task collaboration than did children seen in groups. Independent of intervention format, higher trait-like levels of therapist-rated bond and task collaboration predicted reduced levels of externalizing problems, and higher trait-like levels of child- and therapist-rated task-collaboration and therapist-rated bond predicted reduced levels of internalizing problems. Differences between therapist and child reports of bond predicted weaker reductions in internalizing behavior for children seen in groups. CONCLUSIONS: It is essential to train therapists to develop and assess for TA by midintervention with children with aggressive behavior problems, especially if they are seen in small groups, and to determine if therapists may misperceive the strength of TA. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Predictors of engagement in a school-based family preventive intervention for youth experiencing behavioral difficulties.

The researchers longitudinally assessed parent and child levels of engagement in an evidence-based preventive intervention for children. The sample included 114 fifth graders with aggressive, disruptive behaviors and their parents who participated in the Coping Power Program. Findings indicate that levels of engagement differentially fluctuated for children and parents throughout the course of the intervention. Results also suggest that child levels of engagement early in the course of the program influenced parent mid-intervention levels of engagement. Further, these relationships persisted when the influence of family environment variables were included in analyses.

Mindful Coping Power Effects on Children's Autonomic Nervous System Functioning and Long-Term Behavioral Outcomes.

Mindful Coping Power (MCP) was developed to enhance the effects of the Coping Power (CP) preventive intervention on children's reactive aggression by integrating mindfulness training into CP. In prior pre-post analyses in a randomized trial of 102 children, MCP improved children's self-reported anger modulation, self-regulation, and embodied awareness relative to CP but had fewer comparative effects on parent- and teacher-reported observable behavioral outcomes, including reactive aggression. It was hypothesized that MCP-produced improvements in children's internal awareness and self-regulation, if maintained or strengthened over time with ongoing mindfulness practice, would yield improvements in children's observable prosocial and reactive aggressive behavior at later time points. To appraise this hypothesis, the current study examined teacher-reported child behavioral outcomes at a one-year follow-up. In the current subsample of 80 children with one-year follow-up data, MCP produced a significant improvement in children's social skills and a statistical trend for a reduction in reactive aggression compared with CP. Further, MCP produced improvements in children's autonomic nervous system functioning compared with CP from pre- to post-intervention, with a significant effect on children's skin conductance reactivity during an arousal task. Mediation analyses found that MCP-produced improvements in inhibitory control at post-intervention mediated program effects on reactive aggression at the one-year follow-up. Within-person analyses with the full sample (MCP and CP) found that improvements in respiratory sinus arrhythmia reactivity were associated with improvements in reactive aggression at the one-year follow-up. Together, these findings indicate that MCP is an important new preventive tool to improve embodied awareness, self-regulation, stress physiology, and observable long-term behavioral outcomes in at-risk youth. Further, children's inhibitory control and autonomic nervous system functioning emerged as key targets for preventive intervention.

Mindful Coping Power: Comparative Effects on Children's Reactive Aggression and Self-Regulation.

Coping Power (CP) is an evidence-based preventive intervention for youth with disruptive behavior problems. This study examined whether Mindful Coping Power (MCP), a novel adaptation which integrates mindfulness into CP, enhances program effects on children's reactive aggression and self-regulation. A pilot randomized design was utilized to estimate the effect sizes for MCP versus CP in a sample of 102 child participants (fifth grade students, predominantly low-middle income, 87% Black). MCP produced significantly greater improvement in children's self-reported dysregulation (emotional, behavioral, cognitive) than CP, including children's perceived anger modulation. Small to moderate effects favoring MCP were also observed for improvements in child-reported inhibitory control and breath awareness and parent-reported child attentional capacity and social skills. MCP did not yield a differential effect on teacher-rated reactive aggression. CP produced a stronger effect than MCP on parent-reported externalizing behavior problems. Although MCP did not enhance program effects on children's reactive aggression as expected, it did have enhancing effects on children's internal, embodied experiences (self-regulation, anger modulation, breath awareness). Future studies are needed to compare MCP and CP in a large scale, controlled efficacy trial and to examine whether MCP-produced improvements in children's internal experiences lead to improvements in their observable behavior over time.

Substance Use Outcomes from Two Formats of a Cognitive-Behavioral Intervention for Aggressive Children: Moderating Roles of Inhibitory Control and Intervention Engagement.

Although cognitive-behavioral interventions have reduced the risk of substance use, little is known about moderating factors in children with disruptive behaviors. This study examined whether aggressive preadolescents' inhibitory control and intervention engagement moderates the effect of group versus individual delivery on their substance use. Following screening for aggression in 4th grade, 360 children were randomly assigned to receive the Coping Power intervention in either group or individual formats. The sample was primarily African American (78%) and male (65%). Assessments were made of children's self-reported substance use from preintervention through a six-year follow-up after intervention, parent-reported inhibitory control at preintervention, and observed behavioral engagement in the group intervention. Multilevel growth modeling found lower increases in substance use slopes for children with low inhibitory control receiving individual intervention, and for children with higher inhibitory control receiving group intervention. Children with low inhibitory control but who displayed more positive behavioral engagement in the group sessions had slower increases in their substance use than did similar children without positive engagement. Aggressive children's level of inhibitory control can lead to tailoring of group versus individual delivery of intervention. Children's positive behavioral engagement in group sessions is a protective factor for children with low inhibitory control.

Effects of Autonomic Nervous System Functioning and Tornado Exposure on Long-Term Outcomes of Aggressive Children.

This study examined whether pre-disaster indicators of sympathetic and parasympathetic activity moderated the relation between degree of disaster exposure from an EF-4 tornado and changes in the externalizing and internalizing behavior problems of children at-risk for aggression. Participants included 188 children in 4th-6th grades (65% male; 78% African American; ages 9-13) and their parents from predominantly low-income households who were participating in a prevention study when the tornado occurred in 2011. Fourth-grade children who exhibited elevated levels of aggressive behavior were recruited in three annual cohorts. Parent-rated externalizing and internalizing problems were assessed prior to the tornado (Wave 1; W1), and at 4-12 months (W2), 16-24 months (W3), 42-28 months (W4) and 56-60 months (W5) post-tornado. Children's pre-tornado Skin Conductance Level (SCL) reactivity and Respiratory Sinus Arrhythmia (RSA) withdrawal were assessed at W1 using SCL and RSA measured during resting baseline and during the first 5 min of the Iowa Gambling Task (IGT). Children and parents reported their exposure to tornado-related trauma and disruptions at Wave 3. Children displayed less reduction in externalizing problems if there had been higher child- or parent-reported tornado exposure and less RSA withdrawal, or if they had lower parent-reported TORTE and less SCL reactivity or lower SCL baseline. Highlighting the importance of children's pre-disaster arousal, higher levels of disaster exposure negatively affected children's level of improvement in externalizing problems when children had less vagal withdrawal, and when tornado exposure disrupted the protective effects of higher SCL reactivity and higher SCL baseline.

Theoretical Model of Mindful Coping Power: Optimizing a Cognitive Behavioral Program for High-Risk Children and Their Parents by Integrating Mindfulness.

This paper describes a theoretical model of Mindful Coping Power, a preventive intervention targeting high-risk children and their parents. Mindful Coping Power integrated mindfulness into Coping Power, an evidence-based cognitive behavioral intervention. Reactive aggression is emotionally driven, impulsive, and often referred to as being "hot-blooded." It has been resistant to change, given the high level of emotional arousal and impulsive angry outbursts. Our premise is that mindfulness impacts the mechanisms of reactive aggression-attentional, cognitive, behavioral, and emotional dysregulation. Also in the model are parents who exhibit emotionally charged interactions with their child. Mindful parenting focuses on parents' own emotional self-regulation and being fully present with their child. Our model sets the stage for incorporating mindfulness into existing interventions, thereby optimizing programs and maximizing effects.

The Influence of Treatment Engagement on Positive Outcomes in the Context of a School-Based Intervention for Students with Externalizing Behavior Problems.

We examined the stability of and cross-influences between externalizing behaviors and intervention engagement among children participating in a randomized clinical trial of an intervention for disruptive behavioral youth. Analyses also accounted for the influence of caregiver depression, family relationship quality, and sociodemographic factors (race, income) on the relationship between behaviors and intervention engagement. Analyses were based on 118 children participating in the Coping Power intervention. Composite variables were created to represent externalizing behaviors and intervention engagement constructs. Associations between these composite variables were examined over 24 treatment sessions. Findings indicated a regressive relationship among externalizing behaviors, i.e., baseline externalizing behaviors were positively associated with immediate follow-up behaviors. There were also dynamic relationships observed among engagement constructs. Notably, engagement with in-session activities during sessions 1-8 was positively associated with out-of-session activity engagement during the same treatment time period. Engagement with out-of-session activities during sessions 1-8 was positively associated with in-session activity engagement during sessions 9-16, indicating a complete mediation between early and middle in-session engagement through the mechanism of early out-of-session engagement. A crosslag relationship was observed: middle in-session engagement was negatively associated with externalizing behaviors at immediate follow-up. Finally, an interaction of race by income on immediate follow-up externalizing behaviors was observed, such that Black children's externalizing behaviors remain static regardless of income level while White children's behaviors decreased with higher income. Our findings support the contention that focusing on intervention engagement may be especially important in prevention interventions.

The prevention of conduct problems.

This article summarizes the current knowledge base in the prevention of childhood conduct problems. First, childhood conduct problems and comorbid conditions are described, followed by a review of risk factors that have been found to contribute to the development of conduct problems. Risk factors include both internal child characteristics such as temperament and genetic/neurobiological influences, and external factors such as family, peer, and neighborhood influences. Finally, descriptions are provided for several intervention programs that have demonstrated empirical support in the prevention of youth conduct problems.

Variation in Response to Evidence-Based Group Preventive Intervention for Disruptive Behavior Problems: A View from 938 Coping Power Sessions.

Prior research suggests that under some conditions, interventions that aggregate high-risk youth may be less effective, or at worse, iatrogenic. However, group formats have considerable practical utility for delivery of preventive interventions, and thus it is crucial to understand child and therapist factors that predict which aggressive children can profit from group intervention and which do not. To address these questions we video-recorded group Coping Power intervention sessions (938 sessions), coded both leader and participant behavior, and analyzed both leader and children's behaviors in the sessions that predicted changes in teacher and parent, reports of problem behavior at 1-year follow up. The sample included 180 high-risk children (69% male) who received intervention in 30 separate Coping Power intervention groups (six children assigned per group). The evidence-based Coping Power prevention program consists of 32 sessions delivered during the 4th and 5th grade years; only the child component was used in this study. The behavioral coding system used in the analyses included two clusters of behaviors for children (positive; negative) and two for the primary group leaders (group management; clinical skills). Growth spline models suggest that high levels of children's negative behaviors predicted increases in teacher and parent rated aggressive and conduct problem behaviors during the follow-up period in the three of the four models. Therapist use of clinical skills (e.g., warmth, nonreactive) predicted less increase in children's teacher-rated conduct problems. These findings suggest the importance of clinical training in the effective delivery of evidence-based practices, particularly when working with high-risk youth in groups.

Testing the feasibility of a briefer school-based preventive intervention with aggressive children: A hybrid intervention with face-to-face and internet components.

This study describes the results from a feasibility study of an innovative indicated prevention intervention with hybrid face-to-face and web-based components for preadolescent youth. This intervention includes a considerably briefer set of face-to-face sessions from the evidence-based Coping Power program and a carefully integrated internet component with practice and teaching activities and cartoon videos for children and for parents. The Coping Power - Internet Enhanced (CP-IE) program introduces a set of cognitive-behavioral skills in 12 small group sessions for children delivered during the school day and 7 group sessions for parents. Eight elementary schools were randomly assigned to CP-IE or to Control, and six children at each school were identified each year based on 4th grade teacher ratings of aggressive behavior. Path analyses of teacher-rated disruptive behavior outcomes for 91 fifth grade children, across two annual cohorts, indicated Control children had significantly greater increases in conduct problem behaviors across the 5th grade year than did CP-IE children. This much briefer version of Coping Power provided beneficial preventive effects on children's behavior in the school setting similar to the effects of the longer version of Coping Power. The website materials appeared to successfully engage children, and parents' use of the website predicted children's changes in conduct problems across the year.

Evidence-based preventive intervention for preadolescent aggressive children: One-year outcomes following randomization to group versus individual delivery.

OBJECTIVE: Some research suggests that group interventions with antisocial youth may, on occasion, have iatrogenic effects. This is the first study to test the effects of group versus individual delivery of evidence-based intervention for aggressive children. METHOD: Three hundred sixty fourth-grade children were randomly assigned by school to group coping power (GCP) or individual coping power (ICP). Longitudinal assessments of teacher and parent reports of behavior (Behavior Assessment System for Children [BASC]; Peer Affiliation and Social Acceptance [PASA]) were collected from baseline through a 1-year follow-up. RESULTS: Growth curve analyses revealed that children in both conditions reduced teacher- and parent-reported externalizing behavior problems and internalizing behavior problems by the end of the 1-year follow-up. However, the degree of improvement in teacher-reported outcomes was significantly greater for children receiving an individual version of the program. In addition, children's baseline level of inhibitory control moderated intervention effects, showing children with low initial levels of inhibitory control to respond poorly in teacher-rated outcomes to group interventions compared to those delivered individually. CONCLUSIONS: This study suggests overall benefits to children for either group or individual delivery of the Coping Power program under high-fidelity conditions; however, for children with low levels of initial self-regulation, individualized interventions will likely yield the most significant reduction in externalizing behavior in the school setting in preadolescence.

Multiple stakeholder agreement on desired outcomes for adolescents' mental health services.

OBJECTIVES: This study identified desired outcomes for adolescent mental health services according to various stakeholders-adolescents, parents, and therapists-and examined agreement across these groups of stakeholders. Potential correlates of agreement, including the youth, family, and treatment characteristics, were also tested. METHODS: Interviews were conducted with 170 adolescents aged 11 to 18 years, their caregiver, and their psychotherapist when the adolescents entered community-based outpatient mental health services. Each participant reported up to three desired outcomes, which were coded into 30 outcome categories across five broad outcome domains. RESULTS: Although the most commonly reported desired outcome across all three stakeholder groups was to reduce anger and aggression, relatively poor agreement existed within the adolescent-parent-therapist triads on desired outcomes for individual youths. Almost two-thirds of the triads did not agree on even one of the desired outcomes for the adolescent's treatment, and most kappa statistics reflected poor agreement. Youths and therapists were each more likely than parents to report desired outcomes that were related to the family environment; youths were the least likely to report desired outcomes that were related to youth symptom reduction. Although many potential correlates of agreement were tested, only two variables were significantly associated with the likelihood that the individual triads would agree on treatment goals: youth anxiety disorder was associated with significantly greater agreement, whereas therapist cognitive-behavioral orientation was associated with significantly poorer agreement. CONCLUSIONS: Consistent with the research on adult mental health services, a lack of consensus was found among key stakeholders on desired outcome priorities for adolescent services. This lack of consensus may limit engagement in treatment and the effectiveness of care.

Does a booster intervention augment the preventive effects of an abbreviated version of the coping power program for aggressive children?

Booster interventions have been presumed to be important methods for maintaining the effects of evidence-based programs for children with behavioral problems, but there has been remarkably little empirical attention to this assumption. The present study examines the effect of a child-oriented booster preventive intervention with children who had previously received an abbreviated version (24 child sessions, 10 parent sessions) of the Coping Power targeted prevention program. Two hundred and forty-one children (152 boys, 89 girls) were screened as having moderate to high levels of aggressive behavior in 4th grade, then half were randomly assigned to receive the abbreviated Coping Power program in 5th grade, and half of the preventive intervention children were then randomly assigned to a Booster condition in 6th grade. The Booster sessions consisted of brief monthly individual contacts, and were primarily with the children. Five assessments across 4 years were collected from teachers, providing a three-year follow-up for all children who participated in the project. Results indicated that the abbreviated Coping Power program (one-third shorter than the full intervention) had long-term effects in reducing children's externalizing problem behaviors, proactive and reactive aggression, impulsivity traits and callous-unemotional traits. The Booster intervention did not augment these prevention effects. These findings indicate that a briefer and more readily disseminated form of an evidence-based targeted preventive intervention was effective. The findings have potential implications for policy and guidelines about possible intervention length and booster interventions.