Developmental shifts in irritable behaviors from preschool to school age: Longitudinal network analysis of heterotypic and homotypic continuity.

Background: Irritability comprises a set of behaviors that span normal:abnormal proneness to anger. When dysregulated and developmentally atypical, irritability indicates neurodevelopmental vulnerability for mental health problems. Yet, mental health risk indicators such as irritability likely present differently during specific developmental stages, especially across the crucial transition from preschool to early school age, when the presence of sustained elevated irritability predicts psychiatric disorders, increased impairment, and service use in school-age children. The goal of this study is to chart how behavioral manifestations of irritability unfold and shift across the developmental transition from preschool to early school age and identify key irritability behaviors that are most strongly predictive of other irritability behaviors in the next developmental stage.

Methods: The sample was drawn from the Multidimensional Assessment of Preschoolers Study (MAPS, N=382), a diverse early childhood sample enriched for psychopathology via oversampling for disruptive behavior and family violence exposure. Objective frequency of normative to severe irritability captured as tantrum features and irritable mood across contexts were longitudinally measured at preschool- (M_age=4.49 years, SD=0.83) and early school-age (M_age=7.08, SD=0.94) using the developmentally specified Multidimensional Assessment Profile Scales-Temper Loss. A cross-lagged panel network was estimated to depict the longitudinal predictive connections between individual irritability items from preschool to early school age.

Results: The strongest cross-lagged association was hit/bit/kick during a tantrum at preschool predicting tantrums in normative contexts at early school age. Severe tantrum behaviors (e.g., hit/bite/kick) and difficulty recovering from anger/tantrums at preschool age are key irritability behaviors that predict the development of widespread irritability features in early school age, including severity and length of tantrums, tantrums across contexts, and irritable mood expressions. As development unfolds, severe and violent irritable behaviors in preschool age influence a wide range of less dysregulated irritable behaviors, yet expressed at developmentally abnormally high frequencies, during early school age.

Conclusions: Highlighting the central behavioral indicators of irritability and how expressions change over the crucial transition from preschool to early school age can inform pragmatic clinical screening measures to identify children who experience high levels of key irritability behaviors (i.e., severe tantrums or difficulty recovering from anger or tantrums in preschool-age) and novel interventions to target these behaviors and interrupt the clinical cascade toward entrenched psychiatric disorders.