What are the behavioral clues or signs of Autism Spectrum Disorder (ASD) in an infant?

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From the Guidelines

Infants with Autism Spectrum Disorder (ASD) often exhibit reduced social attention and social communication, increased repetitive behavior with objects, abnormal body movements, and temperament dysregulation between 12 and 24 months of age. According to the study published in Pediatrics in 2015 1, these early markers can be indicative of ASD. Some key behaviors to watch for include:

  • Reduced social smiling by 12 months
  • Limited eye contact
  • No babbling by 12 months
  • No gesturing (pointing, waving) by 12 months
  • Repetitive movements (hand flapping, rocking)
  • Unusual sensory sensitivities or interests
  • Limited interest in interactive play
  • Abnormal body movements
  • Temperament dysregulation

Another study published in Pediatrics in 2015 1 also found that declining trajectories of social communicative behaviors, such as gaze to faces, directed vocalizations, and social smiling, were predictive of ASD diagnoses at 24 months. If you notice several of these signs, it is recommended to consult a pediatrician for evaluation and further autism screening, as early intervention is crucial for better outcomes. Remember, these behaviors alone don't necessarily indicate autism, as development varies among children, and a professional assessment is needed for diagnosis.

From the Research

Behavioral Clues of Autism Spectrum Disorder (ASD) in Infants

  • Early signs of ASD can be detected in infants, and pediatricians play a crucial role in recognizing these signs 2.
  • Infants with ASD may exhibit abnormalities in social communication and repetitive behaviors, which can emerge during the second year of life 3.
  • Additionally, "prodromal features" such as motor and sensory abnormalities can emerge in the first year of life 3.
  • Standardized screening for ASD at 18 and 24 months of age is recommended, as early identification and intervention can improve outcomes 4.

Importance of Early Identification and Intervention

  • Early identification of ASD is critical for promoting improved outcomes related to early intervention 5.
  • Preventive and early intervention strategies in infancy are essential for improving outcomes over the lifespan, with significant cost savings 6.
  • A transdiagnostic perspective can help identify early indicators that may overlap across ASD and other commonly co-occurring disorders, expanding the impact of early identification and intervention research and clinical efforts 6.

Signs and Symptoms of ASD in Infants

  • Core deficits in social communication/interaction and restrictive, repetitive patterns of behavior are common in infants with ASD 4.
  • Infants with ASD may also exhibit co-occurring medical and behavioral conditions, such as disorders of sleep and feeding, gastrointestinal tract symptoms, obesity, seizures, attention-deficit/hyperactivity disorder, anxiety, and wandering 4.
  • Pediatricians should be familiar with the diagnostic criteria for ASD, appropriate etiologic evaluation, and co-occurring medical and behavioral conditions that affect the child's function and quality of life 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Future Directions for Infant Identification and Intervention for Autism Spectrum Disorder from a Transdiagnostic Perspective.

Journal of clinical child and adolescent psychology : the official journal for the Society of Clinical Child and Adolescent Psychology, American Psychological Association, Division 53, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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