Abstract Introduction Irritability has both mood and behavioral manifestations. These frequently co-occur, and it is unclear to what extent they are dissociable domains. We used confirmatory factor analysis and external validators to investigate the independence of mood and behavioral components of irritability. Methods The sample comprised 246 patients (mean age 45 years; 63% female) from four outpatient programs (depression, anxiety, bipolar, and schizophrenia) at a tertiary hospital. A clinical instrument rated by trained clinicians was specifically designed to capture irritable mood and disruptive behavior dimensionally, as well as current categorical diagnoses i.e., intermittent explosive disorder (IED); oppositional defiant disorder (ODD); and an adaptation to diagnose disruptive mood dysregulation disorder (DMDD) in adults. Confirmatory factor analysis (CFA) was used to test the best fitting irritability models and regression analyses were used to investigate associations with external validators. Results Irritable mood and disruptive behavior were both frequent, but diagnoses of disruptive syndromes were rare (IED, 8%; ODD, 2%; DMDD, 2%). A correlated model with two dimensions, and a bifactor model with one general dimension and two specific dimensions (mood and behavior) both had good fit indices. The correlated model had root mean square error of approximation (RMSEA) = 0.077, with 90% confidence interval (90%CI) = 0.071-0.083; comparative fit index (CFI) = 0.99; and Tucker-Lewis index (TLI) = 0.99, while the bifactor model had RMSEA = 0.041; CFI = 0.99; and TLI = 0.99 respectively). In the bifactor model, external validity for differentiation of the mood and behavioral components of irritability was also supported by associations between irritable mood and impairment and clinical measures of depression and mania, which were not associated with disruptive behavior. Conclusions Psychometric and external validity data suggest both overlapping and specific features of the mood vs. disruptive behavior dimensions of irritability.

Irritability is defined as a low threshold to experience anger in response to frustration. It is one of the most common symptoms in youth and is part of the clinical presentation of several disorders. Irritability can present early in life and is a predictor of long-term psychopathology; yet, the diagnostic status of irritability is a matter of intense debate. In the present article, we address two main components of the debate regarding irritability in youth: the misdiagnosis of chronic irritability as pediatric bipolar disorder, and the proposal of a new diagnosis in the DSM-5, disruptive mood dysregulation disorder, whose defining symptoms are chronic irritability and temper outbursts.

Objetivo: Descrever a adaptação transcultural do Affective Reactivity Index (ARI) para o português do Brasil e investigar propriedades psicométricas preliminares da versão adaptada. Método: A adaptação transcultural foi baseada na investigação das equivalências teórica e operacional da versão original do ARI no contexto brasileiro, seguida do processo de tradução, retrotradução e revisão por comitê de especialistas. A análise dos dados foi realizada em uma amostra comunitária de 133 escolares com idade entre 8 e 17 anos para investigar as seguintes características do ARI: 1) estrutura fatorial; 2) consistência interna; 3) validade do construto, comparando as relações diferenciais entre irritabilidade e as dimensões de ansiedade e prejuízo; e 4) parâmetros de teoria da resposta ao item (TRI). Resultados: Uma versão final em português do Brasil do instrumento foi definida e é apresentada. A consistência interna foi boa, e nossa análise confirmou a estrutura unifatorial original do ARI. As correlações do ARI com as dimensões de ansiedade relacionadas a sofrimento foram maiores do que com as dimensões de ansiedade relacionadas a fobias, reforçando a validade do construto. Além disso, escores mais altos no ARI foram associados a maior prejuízo relacionado à irritabilidade. A análise do TRI enfatizou a frequência de perda de controle como essencial para determinar estados patológicos de irritabilidade. Conclusão: A versão em português do Brasil do ARI parece ser muito semelhante ao instrumento original em termos de equivalência conceitual, de itens, semântica e operacional. Nossa análise preliminar reproduz e estende evidências anteriores que confirmam propriedades psicométricas promissoras para o ARI.

Objective: To describe the cross-cultural adaptation of the Affective Reactivity Index (ARI) to Brazilian Portuguese and to investigate preliminary psychometric properties of the adapted version. Methods: Cross-cultural adaptation was based on the investigation of the theoretical and operational equivalences of the original ARI in the Brazilian context, followed by a process of translation, back-translation, and review by a committee of experts. Data analysis was carried out in a community sample of 133 schoolchildren aged 8 to 17 years to investigate the following characteristics of the ARI: 1) factor structure; 2) internal consistency; 3) construct validity comparing differential relationships between irritability and anxiety dimensions and impairment; and 4) item response theory (IRT) parameters. Results: A final Brazilian Portuguese version of the instrument was defined and is presented. Internal consistency was good, and our analysis supported the original single-factor structure of the ARI. Correlations of the ARI with distress-related anxiety dimensions were higher than with phobic-related anxiety dimensions, supporting its construct validity. In addition, higher ARI scores were associated with higher irritability-related impairment. IRT analysis underscored frequency of loss of temper as essential to inform about pathological states of irritability. Conclusion: The Brazilian Portuguese version of the ARI seems to be very similar to the original instrument in terms of conceptual, item, semantic, and operational equivalence. Our preliminary analysis replicates and extends previous evidence confirming promising psychometric properties for the ARI.