Doctors sometimes miscode or misdiagnose **fetal alcohol spectrum disorder (FASD)** cases as **autism spectrum disorder (ASD)** due to overlapping symptoms and a lack of clear diagnostic pathways for FASD. This misclassification can lead to individuals with FASD not receiving the appropriate diagnosis or support tailored to their condition[1][3].
FASD is a complex neurodevelopmental disorder caused by prenatal alcohol exposure, which affects brain development and leads to a range of cognitive, behavioral, and physical impairments. Its symptoms often overlap with those of autism and attention deficit hyperactivity disorder (ADHD), such as difficulties with social interaction, attention, impulse control, and executive functioning[1][2][3]. Because autism is more widely recognized and diagnosed, and because FASD diagnostic services are limited or absent in many healthcare systems, clinicians may default to an autism diagnosis when faced with these overlapping symptoms.
In Ireland, for example, where FASD prevalence is among the highest globally (estimated between 2.8% and 7.4% of the population), there is a significant lack of diagnostic pathways and support services for FASD. This gap contributes to frequent misdiagnosis as autism or ADHD, leaving many individuals without the correct diagnosis or appropriate interventions[1][3]. The stigma and blame often placed on mothers for prenatal alcohol exposure further complicate diagnosis, as families may avoid seeking help due to fear of judgment[1][3].
The diagnostic challenge arises because FASD does not have a single biomarker or definitive test. Diagnosis typically requires a multidisciplinary assessment including medical history, neurodevelopmental evaluation, and confirmation of prenatal alcohol exposure. However, prenatal alcohol exposure is often underreported or unknown, making diagnosis difficult. In contrast, autism diagnosis relies on behavioral criteria and developmental history, which can be more straightforward to assess[2][4].
Recent research efforts aim to improve FASD diagnosis through advanced methods such as machine learning-driven biomarker profiling, which could help distinguish FASD from autism and other neurodevelopmental disorders more accurately[2]. Such innovations may reduce misdiagnosis in the future.
The consequences of misdiagnosing FASD as autism are significant. Individuals with FASD may not receive the specific supports they need, such as interventions targeting executive functioning deficits, sensory processing issues, or behavioral challenges unique to FASD. Moreover, misdiagnosis can affect access to services, educational accommodations, and social support systems tailored to FASD[1][3][4].
In summary, while autism and FASD share overlapping symptoms, the current lack of widespread awareness, diagnostic tools, and clinical pathways for FASD leads to frequent misclassification of FASD cases as autism. Addressing this requires improved education for healthcare professionals, better diagnostic resources, and public awareness campaigns about the risks of prenatal alcohol exposure and the distinct nature of FASD[1][3][4].
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Sources:
[1] RCSI University of Medicine and Health Sciences, “Foetal alcohol spectrum disorder in Ireland: ‘Mothers are blamed, but they’re not supported’,” 2025.
[2] Chung et al., “Machine learning-driven blood biomarker profiling and EGCG treatment in FASD,” Int J Clin Health Psychol, 2025.
[3] Drugs and Alcohol Ireland, “Foetal Alcohol Spectrum Disorder (FASD) in Ireland,” 202
