Links between Positive Emotionality and Later Comorbid Symptoms in Toddlers with ASD

Background: Although generally, positive emotions are protective against both stressors and the development of psychopathology (Hernandez et al., 2015; Rutter, 1987), more intense positive emotionality in infancy may predict later internalizing and externalizing behaviors (Stifter et al., 2008). Positive emotionality in response to real-world situations in toddlers with ASD appears comparable to that of peers with typical development (TD) and developmental delay (Macari et al., 2018), but prospective links between joy and later psychopathology remain unexplored. By preschool age, many children with ASD exhibit internalizing and externalizing symptoms (Gadow et al., 2004; Simonoff et al., 2008); thus the present study aimed to address this gap in knowledge.

Objectives: To examine relationships between directly-assessed and parent-reported positive emotional expression in the second year and symptoms of internalizing and externalizing problems at age 3 in young children with and without ASD.

Methods: Participants included 94 toddlers (Time1: M_age=22mo, range:13-30mo; Time2: M_age=39mo, range:33-47mo), 52 ASD and 42 TD. At Time1, frequency of joy was characterized via parent report (Early Childhood Behavior Questionnaire (ECBQ): Low-Intensity Pleasure subscale (ECBQ_LIP)). Intensity of joyful emotional expression (iEE-Joy) was characterized via direct observation (Laboratory Temperament Assessment Battery (Lab-TAB); Goldsmith & Rothbart, 1999). iEE-Joy across facial and vocal channels was coded during three Lab-TAB episodes designed to elicit joy. At Time2, parents completed the Preschool Anxiety Scale (PAS-R; Total Anxiety score) and the Early Childhood Inventory (ECI-4; Internalizing and Externalizing composites).

Results: In TD children, greater iEE-Joy expressed during the Lab-TAB at Time1 was associated with higher Time2 ECI-4-Internalizing symptoms (r(22)=.665, p<.001) and PAS-R Anxiety (r(27)=.396, p=.041) but not Externalizing symptoms. In the ASD group, iEE-Joy was positively associated with ECI4-Externalizing symptoms (r(30)=.363, p=.049) but not Internalizing or Anxiety symptoms. In the TD children, parent-reported ECBQ-LIP scores at Time1 were negatively associated with ECI-4-Externalizing (r(34)= -.479, p=.002) and PAS-R Anxiety (r(42)= -.360, p=.019) but not Internalizing symptoms. In the ASD group ECBQ-LIP did not significantly predict any later symptoms (ps>.443).

Conclusions: Positive emotionality is a largely neglected area of study in autism research. In toddlers with ASD, directly-assessed intensity of joy was associated with later externalizing symptoms. This finding contrasted with the results for typically-developing toddlers, where, as in previous literature, expression of joy appeared to serve as both a risk and a protective factor: directly-assessed intensity of joy was associated with later internalizing symptoms, while parent-reported frequency of joy during calm activities predicted lower externalizing and anxiety symptoms. Although preliminary, these results suggest that directly-assessed intensity of joy in toddlerhood may be a risk marker for later internalizing and externalizing symptoms in children with and without ASD, while parent-reported frequency of joy during low-key situations may serve as a protective factor against development of externalizing and internalizing symptoms such as anxiety only in typically-developing children. Thus, this study suggests that the pathways to affective and behavioral psychopathology are different for children with and without ASD. Finally, the results underscore the value of a multi-method approach to understanding the development of comorbid symptoms in very young children with ASD.