This review provides a targeted overview of the current focus and methodology of PT/PE intervention research for children with ASD and DBD. As evidenced by the lack of overlap in publication sources in the two groups of studies, the literature bases are distinct from one another, making transfer of knowledge from one field to another most unlikely. There are many similarities between PT/PE programs for the two groups of children, including the continued use of strategies based on operant conditioning principles, the high proportion of males represented, the use of a variety of PT/PE instructional methods, and the incorporation of fidelity measures in about half of the studies. However, a number of differences were elucidated that may provide opportunities for cross-fertilization and integration of the two bodies of knowledge leading to improved care for both populations. This is especially important as it relates to the focus on bridging the research-practice gap.
The differences in the methodology for the PT/PE programs for children with ASD and DBD reflects the status on the evidence-base for interventions in general for these populations. While extensive evidence exists based on randomized clinical trials for children with DBD (Brestan and Eyberg, 1998
), interventions for children with ASD have primarily utilized single-subject designs and have not conducted large-scale randomized clinical trials. In recent years, there has been discussion in the ASD literature on the need to incorporate RCT methodology in the intervention research in order to more accurately examine the efficacy and effectiveness of various treatments for children with ASD (Lord et al., 2005
). There are significant challenges, however, in using this methodology in ASD research such as the lower base rates of ASD than DBD, the heterogeneity of the population, developmental nature of the disorder, ethical considerations of placing children in a control condition, and the sophistication of parents, which makes contamination of the control group highly likely (Lord et al., 2005
; Schopler, in press). Advantages of a clinical trial model include methodological rigor and clear examination of the effects of the independent variable. However, examination of pre-treatment characteristics that may moderate response to the independent variable requires a very high number of subjects in an RCT. On the other hand, single subject design methodology used in ASD studies has particular strengths that may benefit the DBD literature as a greater attention to treatment process variables and elements of change. Single subject designs could compliment RCTs by examining innovative treatments in their early stages to determine readiness for a clinical trial, as well as for individualizing treatment protocol based on specific child and family characteristics (Lord et al., 2005
). Therefore, these two types of research methodology may be complimentary, and useful to the facilitation of more effective treatments in both populations.
The studies from the two groups also differed in their selection of outcome measures. While a majority of DBD studies used structured reports of child and parental functioning, the ASD studies were more likely to use behavioral observations of the child. This difference may reflect the DBD studies' emphasis on procedures targeting a broad range of behavioral and parenting issues and the ASD studies' emphasis on targeting individual child skills. It also reflects the differences in research methodologies employed. While there are limitations of using standardized measures (see Konold et al., 2004
), it may be important to incorporate standardized measures of functioning, which compare across children and are easily completed by a parent or a provider, into ASD research as more large-scale studies are conducted. Standardized questionnaires assessing child functioning developed for DBD populations may also be applicable to children with ASD. For example, the Child Behavior Checklist (Achenbach, 1991
; Achenbach and Rescorla, 2001
) has scales measuring behavior as well as a scale specifically examining characteristics of ASD. Due to the heterogeneity of the ASD population, as well as the focus on teaching parents to facilitate specific child behaviors, idiosyncratic observational coding systems were developed in order to carefully examine changes in the specific child behavior being taught. However, use of these detailed, specific measures makes comparison across studies difficult. Researchers in the ASD community have suggested that the development of standardized observational coding systems would facilitate the comparison of various how they are affected (Dinca et al., 2005
; Lord et al., 2005
). Some standardized observational systems, which examine both child and parent behavior have been developed in the DBD literature (e.g., Dyadic Parent–Child Interactive Coding System, Robin and Eyberg, 1981
). These types of measures might be useful for the ASD PT/PE community as well. In addition, although ASD researchers have studied stress and depression in parents, there is limited research on how they are affected by PT/PE participation (Baker-Ericzén et al., 2006
). Standardized observational assessments and attention to parent factors in ASD may be facilitated by knowledge transfer from the DBD PT/PE literature.
Observational coding systems have been developed for use in DBD research; however, they are used less often than in the ASD studies. While, admittedly, these measures may be time consuming with large samples, it may enhance the validity of the DBD studies to include observational measures, even for a subset of participants. Baseline observational measures are often used in the ASD studies to set goals for PT/PE interventions and individualize procedures for characteristics of each child. DBD studies may benefit from the use of observational measures in the individualization of programs for children. Observational data specifically taken from systematic functional assessments may be particularly useful for this purpose. Functional assessment procedures are being increasingly used in the ASD PT/PE programs and are actually a legal requirement in educational settings through the Individuals with Disabilities Education Act. Teaching parents (including those with children with DBDs) how to systematically identify the functions of disruptive behavior will not only help parents manage problem behaviors at home, but also to understand the procedures when employed by educational professionals at school.
Focus of PT/PE Interventions
Treatment areas chosen as the target or focus of intervention in the two populations differed somewhat from each other. All of the DBD programs mentioned that a main goal of intervention was, at least in part, to improved parenting practices. This is not surprising given the theoretical rationale for improving impaired parent–child interactions in interventions for this population. That is, dysfunctional parenting practices are viewed as directly related to child psychopathology (Patterson et al., 1992
). While early psychoanalytic explanations for ASD cited parenting practices as a possible cause of “autistic” symptoms (Bettelheim, 1967
), research has debunked these notions (e.g., Schreibman, 2005
) and in fact, researchers may be wary of implicating any negative parenting practices in the treatment protocol for ASD. Therefore, in the ASD studies, authors more often reported that the purpose of including parents was to instruct them in methods for teaching their children specific skills (communication, social) or to instruct them to systematically determine the functions of disruptive behaviors through functional assessment procedures. Although authors may discuss difficulties in the parent–child relationship, typically due to the child's developmental disorder, until recently, it has rarely been the focus of intervention (with the noted exception of the Floor Time approach; Greenspan and Wieder, 1998
). This is not to say that the DBD studies did not target specific child skills as well. For example, a number of studies targeted either child or parent problem-solving skills (e.g., Kazdin and Wassell, 2000
). Further, DBD studies also targeted teaching parents to facilitate peer relations (e.g., Webster-Stratton studies of the Incredible Years Program). The DBD studies did not explicitly state that they taught parents to employ functional assessment procedures.
As research moves to focus on implementation in community settings, the focus of PT/PE programs is important. Children in usual care community services may exhibit symptoms similar to that of both populations. For example, children presenting with DBD issues may also have communication delays. Teaching parents strategies to build additional skills, such as appropriate communication, in their children may enhance programs for DBD. Many of the methods taught to parents of children with ASD to enhance child communication skills are relatively simple and have been developed to be incorporated naturalistically into families' daily lives. Since many children with DBD also have communication difficulties, including a focus of communication skills has the potential to greatly enhance the effectiveness of the programs. Further, parents of children with ASD presenting for intervention in community settings may also benefit from basic parenting skills that are standard in most DBD programs. Children with ASD are often very difficult to engage, which may affect basic parent–child interactions leading to similar parenting issues as seen in the DBD populations (Greenspan and Wieder, 1998
Another main area of difference identified under this domain is how parent factors are incorporated into the intervention program. The role of parent factors is an issue that is highly relevant across studies for both populations, although it has been conceptualized differently. Parental stress and depression in parents of children with ASD has often been discussed as a result of raising a child with a disability, while environmental stressors and parental psychopathology has been associated with increased child symptomatology in children with DBD. The results were consistent with these conceptual differences. ASD interventions were much more likely to explicitly state that parents are active collaborators in designing interventions for their children (e.g., Brookman-Frazee, 2004
) and addressing stress as a reaction to the child issues, while DBD interventions were more likely to target parent factors such as stress, depression and marital problems as a structured part of their PT/PE program that are suggestive of causal attributes to child issues (e.g., Kazdin and Whitley, 2003
). Parents of children with DBD may benefit from taking a more active role in choosing intervention methods and goals for their children. This may provide additional confidence in parenting skills, motivating and empowering parents and help improve the parents' view of the child's positive qualities. While collaboration with parents has been discussed in the DBD literature and is a specific component to wraparound program models, it is not highlighted in the empirical literature reviewed here.
While there is significant attention to the increased parental stress associated with raising a child with a severe disability, limited attention has been given to systematically addressing these issues within the context of a parent training intervention. There is research with parents of children with autism indicating that clinical levels of parental stress (not directly related to child-rearing) negatively impacts child gains made during parent training interventions (Plienis et al., 1988
; Robbins et al., 1991
). Some researchers have begun to develop interventions specifically to teach parents of children with severe disabilities coping and stress management skills (Nixon and Singer, 1993
); however, these types of interventions were not systematically incorporated in the empirical research on PT/PE for children with ASD.
A number of the DBD programs have systematically added components targeting parental factors (e.g., stress, coping, problem-solving, communication) and addressing parent and/or other family problems (e.g. parent depression or marital discord) to their treatment protocol. These are typically addressed through adjunctive interventions and have been discussed as a vehicle to enhance parent training (Forehand and Kotchick, 2002
). For example, Griest et al. (1982)
developed Parent Enhancement Therapy as an adjunct to the Helping the Non-compliant Child parent training program that included components targeting marital conflict, symptoms of depression, communication skills, problem-solving skills, and shared pleasant activities by spouses. Likewise, Webster-Stratton and colleagues (e.g., Webster-Stratton and Reid, 2003
) have incorporated a parent-focused component to their basic parenting intervention (The Incredible Years) used with children with conduct problems. Incorporating the direct targeting of parent factors is associated with greater therapeutic changes in the children and the reduction of barriers to participation in family interventions (Kazdin and Whitley, 2003
). These types of adjunct therapies may be beneficial to families of children who have ASD as well. More research is needed for both populations on how to adapt standard therapies for parent characteristics.
There were a number of notable differences between the two areas of research in the area of PT/PE procedures. For example, a significant majority of the ASD studies focused on children under the age of 5 years, while DBD studies crossed the age ranges. This may be explained by the emphasis on early identification and intervention for children with ASD (National Research Council, 2001
). Further, federal early intervention regulations under the Individuals with Disabilities Education Act (IDEA) Part C require that parents be actively included in interventions. Based on the diagnostic criteria for DBDs versus ASDs, children with DBD may be diagnosed later than children with ASD. Early identification of autism in children under age 3 is becoming increasingly common (Charman and Baird, 2002
; Filipek et al., 1999
; Mandell et al., 2005b
Again, this difference in procedures provides the possibility for knowledge transfer between the fields. While the DBD studies spanned the age ranges, there has been a growing movement toward targeting younger children to prevent the development of conduct problems in children who are at risk. For example, in the area of DBD, Webster-Stratton and colleagues have recently focused on targeting families of young children in Head Start programs. As DBD researchers attempt to implement their programs for younger children, they will need to consider the developmental appropriateness of their programs, and may need to modify some of the techniques to fit younger populations. Researchers working with ASD populations have had to do this already (e.g., Koegel et al., 1999
) and may inform DBD researchers in this area. While the importance of early intervention for children with ASD is clear, future PT/PE research in ASD might consider developing programs for parents of older children as their needs may differ significantly from those with younger children, as may the needs of these parents. With the increase in children being diagnosed with ASD, researchers and interventionists are also faced with growing populations of children in need of services through school-age into adolescence and adulthood. Often, behavioral issues and important skill sets change as children grow older. ASD researchers have called for research examining treatment protocol for the increasingly underserved population of older children with mild to moderate ASD (National Institute of Mental Health, 2004
). The DBD literature may provide an excellent source of information for this growing population.
Other differences in PT/PE procedures were noted. For example, while both types of programs often held PT/PE sessions in a clinic-based facility, ASD programs more often provided sessions in the home and DBD studies were more likely to take place in educational settings. DBD studies may find increased generalization of skills learned in PT/PE programs if conducted in children's homes. This may be especially important for the increasing number of DBD studies that target younger children (under age 5) as community-based early intervention programs for young children are often conducted in the home settings. As evidence-based interventions are implemented in “real world” practice, programs developed for use in-home may be more consistent with public service systems.
While both types of programs used a variety of instructional methods to teach parents, there are a few distinct differences. ASD studies were more likely to report using modeling and in-vivo feedback/ coaching and DBD studies were more likely to report using didactic instruction. These differences may be attributed to the differences in the formats. Specifically, ASD studies were more likely to work with individual families, while DBD programs often provided the training in a group format. There are strengths to both of these approaches. Group parent training is a very efficient and cost-effective way to reach parents of a large number of children. This may become increasingly important for the ASD population as the number of children diagnosed with this disorder increases. Further, group treatment provides a forum for parents to collaborate and learn from each other (Webster-Stratton, 1997
). This has been shown to be important in one preliminary study of parents of children with autism who learned the PT/PE techniques better when individual treatment sessions were combined with a support group (Stahmer and Gist, 2001
), however, this has not been systematically examined in the ASD population. Providing PT/PE for individual families, on the other hand, provides more intensive intervention that is more able to individualize the intervention to family and child characteristics. This may be critically important for families of children with ASD, as these children represent a highly heterogeneous group. There may also be families of children with DBD who require more individualized attention to learn parenting techniques or children with particularly challenging characteristics, which require more specific intervention. Future research in both areas may examine who benefits most from the different PT/PE formats and what teaching formats are associated with the greatest generalization and maintenance of skills in both parents and children.
Practical Application of Cross-Fertilization
Overall, the DBD interventions were more likely to teach general parenting skills, while ASD programs were more likely to individually teach parents to facilitate specific child skills (e.g., communication) in the home environment. The ASD programs may benefit from incorporating general parenting skills into the curricula, which could be taught in a group format, and systematically targeting parent factors; and the DBD programs could benefit form targeting individual child skills with the child present. There have been recent attempts to do this. For example, autism researchers are beginning to study the use of Parent–Child Interaction Therapy (a program developed for children with DBD) with families of children who have high functioning ASD and report preliminary success with the procedures (Solomon and Goodlin-Jones, 2004
). Further, Sharry et al. (2005)
have developed an early intervention parent-training program (Parent Plus Early Years Programme) designed for children with disruptive behavior problems and those with a range of mild developmental disabilities. This program builds on both the research on children with DBD and those with developmental and communication delays, by teaching parents a combination of general parenting strategies and specific skills to enhance child communication. Further, this program uses both group video-tape instruction and individual coaching to families. The preliminary research on this program illustrates not only the overlapping needs of the population of children, but also the effectiveness of integrating PT/PE methods developed for the two populations of children.
Another specific practical way to increase cross-fertilization is through research dissemination. One critical finding was no overlap in publication sources for studies of the two populations. Journals may need to be more proactive about publishing research for both populations. National conferences may also need to target attendance of intervention developers for both populations to increase awareness of the relevance of the two bodies of research to one another and increase the synergy of future research, thus enhancing the likelihood that they may be translated into real world practice.
Limitations of Current Review
While our literature search focused on the keywords of “parent training” and “parent education” for DBD and ASD, we are aware that there may be number of other programs that include a parent training or education component that did not come up in our search. For example, multi-component interventions for children with DBD, such as Multi-systemic Treatment (Henggeler et al., 1992
) and Multi-dimensional Treatment Foster Care (Chamberlain and Reid, 1991
) include parent training as a part of a more comprehensive intervention package. In the area of ASD, programs such as Positive Behavior Support, and comprehensive educational programs such as Little Walden, the Denver Model, the Princeton Child Development Institute (see Harris and Handleman, 1994
) and Developmental, Individual-Difference, Relationship-Based/Floortime approach (Greenspan and Wieder, 1998
) were likely not captured in this literature search. Looking to these programs may also inform both the DBD and ASD PT/PE research.
For purposes of this review, we focused on two distinct groups of children for the sake of comparison. However, the PT/PE research is not limited to these groups. For example, there is a considerable amount of PT/PE research conducted on families of children with ADHD (Anastopoulus and Barkely, 1990
; Barkley, 2002
). Further, PT/PE has been employed with children with anxiety problems (Barret and Shortt, 2003
) and depression (Stark et al., 1996
). These studies may be highly relevant to both DBD and ASD as these other conditions often co-occur in both of these populations. In fact, as noted, one of the studies that we did not include targeted children with DBD and/or ASD (Sharry et al., 2005
). This study was not included because it could not be categorized as primarily DBD or ASD; however, it does provide preliminary evidence for the utility of cross-fertilization.
Summary and Conclusions
This review provides a systematic overview of the current (1995–2005) parent mediated intervention literature for two groups of children: those with conduct problems or DBD and those with ASD. While sharing similar roots in operant conditioning, it is clear that the research studies with these populations are represented in distinct bodies of literature. With the emphasis on moving research into community practice and conducting intervention research that is highly relevant to clinical practice, it is important to recognize that these populations may actually overlap in “real world” settings. Therefore, integrating the knowledge gained from recent research with both populations may facilitate the implementation of evidence-based practices in usual care settings. Specifically, examining the research methodology, the focus of parent interventions and actual teaching procedures can inform future implementation and intervention research.