The Complexities of Late Diagnoses in Autism Spectrum Disorder

Liv Mace

In our recent discussion in neuroscience, we discussed the social and professional implications of late autism diagnoses. We read a systematic review by Russell et al. (2025), which revealed that the definition of a “late" diagnosis proved remarkably inconsistent across research literature, with studies presenting age ranges from 3 to 18 years. We think this was due to the paper’s consideration for inclusive samples. The average age of diagnosis across all the studies mentioned in the paper was 11.5, which surprised some of us as we had assumed most would have been diagnosed shortly after entering elementary school at the latest. We looked at the significance of diagnostic timing, and we agree that early intervention can optimize brain development and support if sought out early enough by the age of 3.  

We also explored the value of late diagnosis by recognizing they offer more than just clinical categorization. While an early diagnosis is preferred, for many individuals a later diagnosis still provides crucial validation, explaining lifelong experiences of differentness. A diagnosis at any stage offers a framework for understanding their own personal experiences. Late diagnoses can also be valuable for individuals to afford healthcare since a diagnosis is necessary for treatment and interventions.  
Additionally, the emerging trend of self-diagnosis, which we believe has been amplified through social media platforms and an abundance of time available to people during COVID-19, brought a shift in our discussion. We talked about the delicate balance between respecting individual experiences while also maintaining scientific integrity. We do believe that self-identification can provide meaningful personal insights, but it can also present challenges for standardized research methodologies that require precise diagnostic criteria. Lastly, we discussed the outcome of self-diagnoses compared to traditional diagnoses and how this can contribute towards stereotypes. 
Ultimately, diagnoses need to be based on the DSM5 to uphold scientific integrity. We agree that diagnoses, especially in autism spectrum disorder, is not a simple process of checking diagnostic boxes but an exploration of individual experiences best guided by the help of a licensed professional. The process of diagnosing autism is complex, and our discussion this week aimed to acknowledge this to better understand and communicate with individuals who participate in our studies. 
 
Russell, A. S., McFayden, T. C., McAllister, M., Liles, K., Bittner, S., Strang, J. F., & Harrop, C. (2025). Who, when, where, and why: A systematic review of “late