Utility of Temperament for Predicting Psychopathology in Infants with Early Signs of Autism Spectrum Disorder (ASD)

Background: High rates of internalizing and externalizing psychopathology are reported among individuals with a diagnosis of Autism Spectrum Disorder (ASD). However, the mechanism/s underlying this pattern of co-morbidity remain poorly understood. Abundant research on normative development suggests that individual differences in early temperament characteristics can promote either risk or resilience to the development of psychopathology. Surprisingly, only a handful of studies have explored the relation of temperament to psychopathology in the context of ASD. These existing studies explored associations between psychopathology and individual temperament traits, as opposed to multiple-trait configurations which more aptly describe each person as a whole. Further, existing studies restricted their focus to individuals with established ASD diagnosis, limiting generalizability to early development when behavioural features of ASD and psychopathology first emerge.

Objectives: To (a) identify distinctive temperament subgroups within a cohort of infants presenting with early signs of ASD and (b) explore the utility of these temperament subgroups for predicting variability in internalizing and externalizing symptoms.

Methods: Participants were a community-referred sample of 96 infants (67.7% male) aged 9-16 months (M = 12.38, SD = 1.94) showing early signs of ASD. Parents/carers completed the Infant Behavior Questionnaire-Revised (IBQ-R), a 191-item measure of infant temperament, and the Infant-Toddler Social and Emotional Assessment (ITSEA), a 161-item measure of social-emotional and behavioural problems. Latent profile analysis was used to identify temperament subgroups from IBQ-R subscale scores, and one-way ANOVA were used to explore between-subgroup differences across ITSEA domains/scales.

Results: Three temperament subgroups were identified: (1) well-regulated (n = 51), characterized by high cuddliness, falling reactivity, and soothability, (2) active/negative reactive (n = 23), characterized by high activity level, distress to limitations, sadness, fear, and low falling reactivity, and (3) inhibited/low positive (n = 22), characterized by low smiling and laughter, high intensity pleasure, vocal reactivity, approach, and perceptual sensitivity. Active/negative reactive infants had the highest levels of separation distress and broad externalizing symptoms, while inhibited/low positive infants had the highest levels of depression/withdrawal. Both active/negative reactive and inhibited/low positive subgroups had higher levels of broad internalizing symptoms than well-regulated infants, who had the lowest reported levels of co-morbid psychopathology. There were no differences between temperament subgroups with respect to age, sex, or developmental/cognitive ability. Inhibited/low positive infants presented with more ASD features than the other subgroups.

Conclusions: Temperament characteristics may contribute to variability in internalizing and externalizing symptoms in young children with early signs of ASD. This study provides an empirical foundation for the development of individualized interventions for the prevention and treatment of co-morbid psychopathology in ASD. The person-centered approach utilized in this study afforded a more nuanced understanding of temperament-psychopathology relations, and the broad inclusion criteria for participant infants extends the generalizability of results across the full continuum of ASD feature presentation.