Is It Autism or Another Diagnosis?

Many concerned parents seek a diagnostic assessment to see whether their child’s social communication and behavior meet the diagnostic criteria for autism spectrum disorder (ASD), or in response to concerns about their child’s emotional or sensory challenges.

Some parents can be unaware that there are many conditions that, at face value, share common characteristics with autism and can present quite similarly. This is understandable given that the presentation of autism is very heterogeneous and not only has characteristics that overlap with many other conditions, but also are present in the neurotypical population. I wrote this post to support parents who are considering an ASD assessment to be aware of a few common differential diagnoses that share similarities to ASD and gain clarity about what constitutes criteria for ASD, to empower them in seeking answers about how to support their children.

When making an ASD diagnosis, it is important to go on a journey of investigating whether an individual meets the entire diagnostic criteria for ASD (as outlined in the most recent Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, or in the World Health Organization’s International Classification of Diseases, 10th Edition).

This includes a dyad of characteristics relating to social communication and restrictive and repetitive patterns of behavior, that are further broken down into more specific categories within the DSM. The DSM-5 criteria also include a rating of severity of symptoms and an acknowledgement of the impact of atypical sensory processing. The autistic characteristics have to be present in the early developmental period of an individual.

To meet diagnostic criteria relating to social communication, the clinician investigates whether an individual meets the criteria for all three of (1) deficits in social-emotional reciprocity, (2) deficits in nonverbal communication behaviors used for social interactions, and (3) deficits in developing, maintaining, and understanding relationships. These must be demonstrated across multiple contexts.

Many individuals experience difficulties with social relationships, which may present as autism at face value, however, have various underlying reasons. For instance, children with an underlying language delay may not know what to say to peers when joining in play activities, which may manifest as anxiety and social withdrawal. In addition, children with (for instance) developmental language disorder have been found to experience higher rates of anxiety disorders, social challenges, emotional regulation challenges, and repetitive/restrictive behaviors (Burnley et al., 2023). However, if they demonstrate awareness of aspects of nonverbal communication such as demonstrate a pattern of being aware of nonverbal cues from peers, spontaneously make use of nonverbal gestures to communicate with others, and appearing to intuitively infer emotions of others, even in one setting, they may not meet all of the criteria relating to social communication.

Another example of a diagnosis that may involve social communication challenges however for reasons other than an underlying diagnosis of autism is borderline personality disorder (BPD). BPD and ASD are frequently confused with one another, with many autistic individuals being diagnosed with BPD and vice versa. The two diagnoses can alco co-occur. Individuals with BPD oftentimes experience challenges with social communication, however the underlying process relates to cognitive biases associated with rejection/abandonment and anxious attachment. These may appear at face value as withdrawal from social interactions, defensiveness, vulnerability, and social anxiety.

Other conditions associated with social communication challenges include ADHD, where children may miss social cues due to inattention, as opposed to atypical comprehension of nonverbal cues (Sokolova, 2017); hearing impairments (Simms, 2017); and numerous genetic conditions such as Fragile X syndrome or Rett syndrome (Simms, 2017).

The other half of the dyad of ASD characteristics relates to repetitive patterns of behavior. Just as is the case for social communication characteristics, numerous conditions share this common characteristic with autism, some examples include developmental language disorder, global developmental delay, or ADHD.

The ASD diagnostic process relies on a clinician’s “best estimate clinical judgement based on behavioral presentation of the individual in the context of their developmental and medical history,” as autism does not have identified biological markers as yet (Whitehouse et al., 2018).

To help differentiate between the various differential diagnoses clinicians make use of standardized assessments for initial screening and to support their investigation into how an individual’s behavior aligns with the diagnostic criteria. Some examples of instruments that help clinicians investigate social communication and repetitive and restrictive behaviors include the Autism Diagnosis Interview–Revised (ADI-R), Autism Diagnostic Observation Schedule (ADOS), Autism Rating Scale (CARS), Gilliam Autism Rating Scale–Second Edition (GARS-2), Social Communication Questionnaire (SCQ), or Social Responsiveness Scale (SRS-2).

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In addition to the above assessments, other information collected during a diagnostic assessment (as recommended by the National Guideline for the Assessment and Diagnosis of Autism Spectrum Disorders in Australia) includes medical and health history, family history, developmental and educational history, functioning abilities (in a variety of settings), or observed and expressed support needs, to name a few. Clinicians additionally review existing assessments and make observations of an individual in a multitude of settings (or collect information about an individual’s functioning in various contexts) including informal observation during the assessment process.

The National Guideline for the Assessment and Diagnosis of ASD highlights the importance of identifying “strengths, skills, interests, resources and support systems of an individual and their support network” in addition to identifying an individual’s challenges (Whitehouse et al., 2018). It stresses the importance of a person-centered and family-centered approach, acknowledging the family’s unique insights into the needs and strengths of the family unit.

In addition to establishing whether an individual meets the criteria for ASD, an additional assessment goal is to identify and prioritize support needs and goals, including recommending appropriate follow-up services.

The diagnostic ASD process is amongst the most comprehensive and extensive assessment journeys. The more parents are informed about the specifics of ASD's diagnostic criteria and aware of commonly occurring suggestions for differential diagnoses, the more empowered they are to ask questions about the particulars of the child's symptoms and ultimately find well-matched supports that meet their child's and family's needs.

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