A road map for identifying autism spectrum disorder: Recognizing and evaluating characteristics that should raise red or “pink” flags to guide accurate differential diagnosis

Objective: Given the high population prevalence of Autism Spectrum Disorder (ASD) and overlapping symptoms with medically complex groups, ASD is a common rule out diagnosis for neuropsychologists even when not identified in the referral or initial presenting concerns. This paper presents practical guidance to support neuropsychologists in their ability to accurately assess, diagnose, and/or rule out ASD, especially in patients with more subtle presentations. Method: This paper combines clinical experience and empirical literature to highlight important assessment measures and related considerations, differential diagnostic considerations, common misconceptions about ASD and person/family characteristics, as well as variability in presentation and comorbidities that can obscure the diagnosis. Characteristics that may be considered “red flags” (clearly diagnostic, classic symptoms) and “pink flags” (associated features and symptoms that are suggestive of ASD but not quite definitive and that may overlap with symptoms seen in other neurodevelopmental or psychiatric diagnoses) will be discussed. Conclusions: Neuropsychologists in all clinical settings should be able to effectively screen for and/or diagnose ASD, even when its presentation is more subtle and/or when symptoms are masked by patient strengths in a way that makes their clinical presentation less obvious. Practical strategies for communicating the diagnosis and next steps/recommendations for interventions are reviewed.