Associations between Fear and Later Anxiety and Internalizing Symptoms in Very Young Children with ASD

Background: Seventy percent of school-age children with ASD have at least one comorbid disorder, anxiety among the most common (Simonoff et al., 2008). Anxiety disorders in the general population are often preceded by the presence of behavioral inhibition, a characteristic that includes fear and reticence (Biederman et al., 2001; Rosenbaum et al., 1993). Although a previous study reported lower levels of fear in toddlers with ASD compared to TD and DD peers (Macari et al., 2018) and another investigated concurrent relationships between fear and anxiety in preschoolers with ASD (Scherr et al., 2017), links between fear and later comorbid anxiety in young children with ASD have not yet been examined.

Objectives: To examine the associations between fearful emotional expression and temperament in the second year and comorbid anxiety and internalizing symptoms at age 3.

Methods: Participants included 95 children (Time1: M_age=22mo, range: 13-30mo; Time2: M_age=39mo, range: 33-47mo): 53 with ASD and 42 typically-developing (TD). At Time1, fear was assessed both via parent report (ECBQ-Fear) and direct assessment (Laboratory Temperament Assessment Battery (Lab-TAB); Goldsmith & Rothbart, 1999). Intensity of emotional expression of fear (iEE-Fear) across facial and vocal channels was coded during three Lab-TAB episodes designed to elicit fear. At Time2, parents completed the Preschool Anxiety Scale (PAS-R; Total Anxiety Symptom score) and the Early Childhood Inventory-4 (ECI-4; Internalizing composite).

Results: In the children with ASD, iEE-Fear expressed during the Lab-TAB at Time1 was associated with Time2 ECI-4-Internalizing symptoms (r(29)=.50, p<.01), but not with PAS-R Anxiety symptoms. Conversely, iEE-Fear in the TD group marginally predicted later PAS-R Anxiety symptoms (r(27)=.34, p=.08), but not ECI-4-Internalizing symptoms. In the ASD group, parent-reported ECBQ-Fear at Time1 was associated with both PAS-R Anxiety symptoms (r(53)=.41, p<.01) and ECI-4-Internalizing symptoms (r(48)=.29, p<.05) at Time2. In the TD group, ECBQ-Fear at Time1 was associated with later PAS-R Anxiety symptoms (r(42)=.29, p=.05) only.

Conclusions: This study suggests a significant role for fear in the development of anxiety and internalizing symptoms for young children with ASD as well as TD children. Our study also indicates that at age 2, direct and parent-reported measures of fearful emotional expression provide somewhat complementary accounts of behavior relevant to later emotional difficulties. In toddlers with ASD, both directly-assessed fear and parent-reported fear predicted a broad set of internalizing symptoms including anxiety at age 3. This differed from TD children, for whom both indices of fear predicted later anxiety symptoms only, consistent with previous studies. Divergent longitudinal patterns of association indicate that pathways to comorbid anxiety and other internalizing symptoms may be different in each group. The data also underscores the importance of a multi-method approach in understanding the development of anxiety and other internalizing symptoms in ASD, and thus, potential treatment targets.