The current study is the first to use network analysis to examine the structure of the eight DSM-5 ODD symptoms (APA, 2013) in a group of primary school-aged children, based on parent and teacher ratings. It examined the centrality of the ODD symptoms in the network, the edge weights for the ODD symptom pairs, and the stability and accuracy of indices for centrality and edges.
Topology of the ODD symptom in the Networks
Overall, there was reasonable level of comparability in the topology of the ODD symptom networks across parent and teacher ratings. For both parent and teacher ratings, touchy, angry, and spiteful were linked together relatively closely in one section of the network, and temper, argue, defy, annoy, and blames others were linked together relatively closely in a different section of the network. For parent ratings, angry was placed more to the center of the network, having connections with all, except the symptom for argue. For teacher ratings, annoy was placed more to the center of this network, and it was linked to all other symptoms in the network.
ODD Network Findings
For parent ratings, the highest strength centrality values were angry, followed by argue. It therefore follows that for parent ratings, angry and argue may be most important ODD symptoms. For teacher ratings, the highest strength centrality values were angry, followed by defy, thereby indicating that for teacher ratings, angry and defy may be the most important ODD symptoms.
For both parent and teacher ratings, there was high connectivity between the symptoms, thereby raising the possibility that many of the ODD symptoms are closely connected with each other. For both parent and teacher ratings the edge weights with at least medium effect sizes were for temper and argue, defy and argue, blames others and annoy, and spiteful and angry. For teacher ratings only, this was also so between annoy and defy. For both parent and teacher ratings, the edge weights between defy and argue, and spiteful and angry, were of large effect sizes. Overall, therefore, there was high degree of comparability in terms of the centrality and edge weights of the symptoms across parent and teacher ratings.
Comparison of Current and Past ODD Network Findings
Although there have been three studies that have examined networks that included the OSS symptoms (Hukkelberg & Ogden, 2018, Preszler & Burns, 2019, Smith et al., 2017), only the Smith et al. study focused exclusively on DSM-5 ODD symptoms, based on parent ratings. Preszler and Burns (2019) examined the network structure of DSM-5 ODD symptoms together with ADHD symptoms, and Hukkelberg and Ogden (2018) examined the network structure of ten relevant ODD symptoms and not the eight DSM-5 ODD symptoms. Given this, only the network for ODD in the Smith et al. study provides an appropriate comparison with the findings in the current study, and that with the findings derived from parent and not teacher ratings. In both studies, for parent ratings, all the symptoms were relatively evenly disbursed in the network. However, as already noted, in the current study, the two symptoms (in descending sequence) with the highest strength centrality values were angry, and argue parent ratings. In contrast, the findings in the Smith et al. study showed that the symptoms for angry, annoys, and argues were central in the network, with anger being most central. Thus, although there were some differences, there was reasonable comparability in the findings in the current study and that reported in the Smith et al. study. This is so, despite major differences across these studies. In contrast to the current study that examined primary-school age children from the general community in an Asian country (Malaysia), Smith et al. examined the network of the ODD symptoms in a group of preschool children with and without ODD in a US sample. Additionally, the Smith et al. study used zero order correlations in the network analysis, whereas the current study used regularized partial correlation. Taking all these into consideration, it can be argued that existing findings from network analysis of ODD symptoms are robust.
Novel Clinical Implications
Our findings have novel implications for theory, classification, assessment and diagnosis, and treatment and prevention. We focus here on the major implications.
Firstly, in a network, symptoms with high centrality values are considered most influential in producing or maintaining the disorder. For parent ratings, the highest strength centrality values were angry, followed by argue, and for teacher ratings, it was angry, followed by defy. Thus it can be argued that the angry, argue, and defy symptoms are especially important for understanding and diagnosis of ODD. Individuals with serious problems related to angry and/or argue are likely to demonstrate or to be at risk for more serious ODD presentations. Thus clinicians may wish to pay special attention to the presence of these symptoms during assessment and diagnosis of ODD. For both respondents, the spiteful symptom had the lowest centrality value, and therefore this symptom may not be critical for ODD.
Secondly, the theoretical importance of a symptom is traditionally viewed in terms of its severity which is ascertained in terms of its mean score. The two most severely rated symptoms were temper and touchy for parent ratings, and angry and temper for teacher ratings. However given that in the network analysis for parent ratings, the highest two centrality symptoms were angry and argue, and for teacher ratings, it was angry and defy, different conclusions about what are core symptoms in ODD are found when looking at symptom centrality compared to symptom severity (Mullarkey et al., 2019). Thus it will be useful for clinicians to also consider symptom centrality when assessing and treating children with ODD.
Thirdly, because the symptoms with high centrality values are considered most influential, intervening on these symptoms could maximize the impact of an intervention, including reducing the effects of other symptoms. This, therefore, could mean that focusing intervention efforts on angry, argue, and defy symptoms rather than the other symptoms could maximize treatment effects, and also likely cascade to reduce the effects of other symptoms. Where relevant, focusing on the symptoms with high centrality values (angry, argue, and defy in the case of ODD) may also prevent the on-set and development of ODD in the context of primary prevention protocols implemented in the community.
Fourthly, the edge weights for parent ratings showed zero values for argue with touchy and angry, and annoy with touchy. For teacher ratings, the values were zero for temper with spiteful, argue with blames others and spiteful, defy with blames others, annoy with anger, and blames others with spiteful. The absence of a connection between two symptoms in a network implies that they are conditionally independent of each other given the other symptoms in the network. Thus the absence of connections for these pairs of symptoms could mean that the symptoms in these relations are conditionally independent of each other. This is a novel finding and indicates that there may be a need to review the relevance of some of the DSM-5 symptoms for ODD.
Fifthly, for both parent and teacher ratings there was one group of closely linked symptoms comprising touchy, angry, and spiteful symptoms (group 1), and another group of closely linked symptoms comprising temper, argue, defy, annoy, and blames others symptoms (group 2). Viewed in terms of how the ODD symptoms are grouped in DSM-5, the first group for both respondents can be considered as an irritability/spiteful group, and second group can be considered as a defiant group. For parent ratings, the highest strength centrality values were angry, followed by argue. As angry and argue are symptoms in the irritability/spiteful and defiant groups, respectively, it follows that for parent ratings, angry may be the most important symptom for the irritability/spiteful group, and argue may be most important symptom for the defiant group.
For teacher ratings, the highest strength centrality values were angry, followed by defy. As angry, and defy are symptoms in the irritability/spiteful and defiant groups, respectively, it follows that for teacher ratings, angry may be most important symptom for the irritability/spiteful group, and defy may be most important symptom for the defiant group. Thus, there was some degree of comparability in terms of the centrality of the symptoms across parent and teacher ratings, especially for the irritability/spiteful group. Also, across the two symptom groups, the dominant connections were temper and argues for parent ratings, and spiteful and angry for teacher ratings.
Sixthly, as the irritability/spiteful group comprised the irritability and spiteful DSM-5 ODD symptoms, and the defiant group comprised the DSM-5 ODD defiant symptoms, the findings suggest the possibility that unlike how the ODD symptoms are grouped in DSM-5, the spiteful symptom could be placed in the angry/irritable symptom group, rather than on its own. Also, when ODD symptoms are viewed in terms the latent variable framework, a two-factor model (with latent factors for irritability/spiteful and defiant) may be most appropriate. To date ODD models with one symptom group comprising touchy, angry, and spiteful, and another symptom group comprising temper, argue, defy, annoy, and blames others, has not been proposed (see Supplementary Table S1). This model may be worthy of exploration in future studies.
Summary of Findings in the Study
The most central ODD symptom for parent ratings was angry, followed by argue. For teacher ratings, it was angry, followed by defy. For both parent and teacher ratings, the networks revealed at least medium effect size connections for temper and argue, defy and argue, blames others and annoy, and spiteful and angry. Overall, the findings were highly comparable across parent and teacher ratings, thereby attesting to their robustness. Also worthy of note is that the stability and accuracy of indices for centrality and edges were supported.
Limitations and Directions for Further Studies
Despite the positive value of the findings in the current study, the results in the study have to be interpreted in the light of a number of limitations. Firstly, as the study showed only moderate stability and accuracy for edge weights, the edge weight findings need to be interpreted with some caution. Secondly, network analysis assumes that mental disorders (and therefore ODD) are causal systems. However as we used cross-sectional data in the current study, causality cannot be securely assumed. At best, we were able to eliminate spurious candidates for causal relations. Causality assessment would require longitudinal data, collected repeatedly. Further studies may wish to examine such concerns, using longitudinal network analysis. Thirdly, as we conducted the network analysis using a normative-community sample, the findings cannot be directly generalized to other samples, like specific racial and clinical groups. Fourthly, as we used parent and teacher rating measures, the findings may not be applicable to data collected via clinical interviews, or from other sources. Fifthly, as our findings are based on group-level analyses, it may not be directly applicable at the individual level. It is possible that some of the associations found in the current study may not be applicable to some individuals. Clearly, we need more network studies of the ODD symptoms, using longitudinal data, collected using multiple sources and methods and different racial and clinical groups. Individualized networks would also be beneficial for a comprehensive understanding of the ODD network. Despite these limitations, our findings do offer novel insights on the structure of ODD symptoms, their relative importance that can be used effectively for theorizing, assessing and treating ODD.