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Signs of ASD in Older Children and Adults


With so much focus placed on early diagnosis of Autism Spectrum Disorder (ASD), one area that is sometimes overlooked is the diagnosis of ASD in older children and adults. The reality is that many individuals with mild symptoms of ASD are able to blend in and avoid detection until they are in middle school, high school, or even adulthood. These individuals may have had early warning signs which were overlooked, mischaracterized, or ignored. Yet looking backward, something always seemed to be "off." Maybe the individual just seemed to prefer to be alone, or maybe they just appeared awkward to friends and family. These characteristics alone are not enough to diagnose someone with ASD. But if you are reading this post, you may be wondering if this awkwardness or loneliness, combined with other traits, could be attributable to ASD.

While the diagnostic criteria for ASD are no different for children and adults, there are certain traits that are more or less likely to be found in an adult receiving a diagnosis for the first time. For example, it is unlikely that an adult who has gone undiagnosed for a lifetime is unable to speak to the point of being considered nonverbal. Additionally, as children get older, there are higher expectations for social interactions. What was once considered tolerable in a child is no longer socially accepted in an adult, and while an individual may have had enough skills to manage the more basic social interactions of childhood or even adolescence, the nuances and complexities of adult relationships may be much more challenging. The demands of life become more complicated as an individual ages, and sometimes it is not until the individual is older that the full effect of ASD is observable to friends and family. Of course, there are adults who have been misdiagnosed as children, perhaps with schizophrenia or mental illness of another kind. In these situations, the misdiagnosis may have blinded medical professionals and others from looking at the true causes of symptoms, and may have even led to treatments which have been detrimental to the progress of the misdiagnosed individual.

The current diagnostic criteria for ASD contained within the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) are discussed in a separate article. Below is a list of some symptoms related to ASD that may be particularly observable and impairing in older children and adults who are as yet undiagnosed:

  • Difficulty picking up on social cues, including reading body language and understanding subtle differences in speech tone that may indicate sarcasm
  • Difficulty making conversation, especially taking turns speaking
  • Talking a lot, particularly about a preferred subject
  • Dislike of change
  • Difficulty adjusting the formality of language for the audience, for example, speaking differently to teachers or supervisors than peers
  • Tendency to avoid eye contact
  • Unusual or inappropriate facial expressions
  • Preoccupation with a special interest, particularly one that may seem odd to others
  • Awkward motor movements or poor handwriting
  • Over- or under-sensitivity to certain sounds, sights, or textures
  • Few or no friends
  • Easily frustrated, sometimes leading to emotional meltdowns, withdrawal from a situation, or aggression
  • Self-injurious behaviors
  • Anxiety or depression

While a few of these symptoms alone are not enough to indicate ASD, you may want to consult a professional diagnostician for a full evaluation. Even if they are not indicative of ASD, they may be symptoms of another condition, which could be treated effectively.

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The Center for Autism Research and The Children's Hospital of Philadelphia do not endorse or recommend any specific person or organization or form of treatment. The information included within the CAR Autism Roadmap™ and CAR Resource Directory™ should not be considered medical advice and should serve only as a guide to resources publicly and privately available. Choosing a treatment, course of action, and/or a resource is a personal decision, which should take into account each individual's and family's particular circumstances.