Social motivation in infancy is associated with familial recurrence of ASD

Area of Science:

• Neurodevelopmental disorders
• Autism Spectrum Disorder (ASD) research
• Child psychology and development

Background:

• Autism Spectrum Disorder (ASD) is a heritable neurodevelopmental condition.
• Pre-diagnostic deficits in social motivation are hypothesized to play a role in ASD development.
• Understanding early markers of ASD is crucial for timely intervention.

Purpose of the Study:

• To evaluate the psychometric properties of a parent-report Social Motivation Index (SMI).
• To determine if lower SMI scores in infancy are associated with a later ASD diagnosis.
• To examine how social motivation changes in relation to familial ASD risk.

Main Methods:

• Utilized parent-report data from 597 infant siblings in a prospective high- and low-risk cohort for ASD.
• Assessed the Social Motivation Index (SMI) at 6, 12, and 24 months of age.
• Analyzed the association between SMI scores, ASD diagnosis, and familial ASD liability.

Main Results:

• The SMI demonstrated good internal consistency and temporal stability.
• Children diagnosed with ASD showed lower mean SMI T-scores at all assessed ages (6, 12, 24 months).
• A significant decline in SMI T-scores across age was observed in children with ASD, with steep declines associated with a 10-fold increased odds of diagnosis in high-risk infants.

Conclusions:

• Infant social motivation is quantifiable via parental report and can serve as an early marker for ASD.
• Lower social motivation by 6 months of age differentiates infants who later receive an ASD diagnosis.
• The course of social motivation tracks with familial ASD liability, supporting its role as a potential diagnostic and susceptibility marker for ASD.