From the Guidelines
Autism Spectrum Disorder (ASD) can be reliably diagnosed as early as 18-24 months of age. Early signs of autism may be detectable in some infants as young as 6-12 months, particularly in high-risk cases such as those with affected siblings. Diagnosis involves comprehensive developmental evaluations by specialists including developmental pediatricians, child neurologists, child psychologists, or child psychiatrists who assess social communication, behavior patterns, and developmental history. The American Academy of Pediatrics recommends autism-specific screening for all children at 18 and 24 months during regular well-child visits, in addition to ongoing developmental surveillance 1. Early diagnosis is crucial because it allows for earlier intervention, which can significantly improve outcomes by taking advantage of greater brain plasticity in younger children. While some mild cases might not be identified until school age when social demands increase, healthcare providers are increasingly focused on identifying signs earlier to maximize the benefits of early intervention services. Some key points to consider include:
- The importance of early screening and diagnosis for ASD, as highlighted in studies such as those published in Pediatrics 1
- The role of comprehensive developmental evaluations in diagnosing ASD, as noted in research on diagnostic stability 1
- The need for ongoing developmental surveillance and autism-specific screening at 18 and 24 months, as recommended by the American Academy of Pediatrics 1
- The potential benefits of early intervention for children with ASD, including improved outcomes and greater brain plasticity 1
From the Research
Age of Autism Diagnosis
The age at which Autism Spectrum Disorder (ASD) can be diagnosed is a topic of interest in the field of autism research.
- Studies have shown that ASD can be diagnosed with a high degree of reliability between the ages of 18 months and 2 years 2.
- Some research suggests that symptoms of autism can be detected as early as 6-12 months, although these symptoms may be of limited diagnostic interest at this stage 2.
- A study published in 2019 found that the diagnostic stability of ASD in toddlers starting at 12 months of age is relatively high, with a stability coefficient of 0.84, and that this stability increases with age, reaching 0.79 by 14 months and 0.83 by 16 months 3.
- Another study found that the diagnosis of autism at age 2 is more stable than the diagnosis of PDD-NOS at the same age, with social deficits and delays in spoken language being the most prominent characteristics evidenced by very young children with autism 4.
- Factors associated with earlier diagnosis of ASD include greater symptom severity, high socioeconomic status, and greater parental concern about initial symptoms, as well as geographic variation in access to community resources and state policies 5.
- The importance of early diagnosis is highlighted by the fact that it opens the door to early intervention programs, which can prevent many problems from occurring in later life 6.