Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jul 1;17(1):35.
doi: 10.1186/s11689-025-09627-3.

Pathways to autism diagnosis in adulthood

Isabelle Dufour  1   2 , Yohann Chiu  3   4 , Sébastien Brodeur  5   6   7 , Mireille Courteau  3 , Josiane Courteau  3 , Émilie Dubé  8 , Alain Lesage  9 , Éric Fombonne  10 , Mélanie Couture  8
Affiliations

Pathways to autism diagnosis in adulthood

Isabelle Dufour et al. J Neurodev Disord. .

Abstract

Background: This study explored Trajectories of Diagnoses (TDs) preceding a first diagnosis of autism in adulthood.

Methods: This retrospective cohort study used health administrative data from Quebec, Canada, and included all adults with a first recorded diagnosis of autism between 2012 and 2017. A TDs was defined as a succession of medical records of psychiatric and/or neurodevelopmental conditions over time. These TDs were retrospectively analyzed from 2002 to 2017, using a state sequence analysis of diagnoses, in order: Autism, Intellectual or developmental disabilities (IDDs), Schizophrenia spectrum disorder (SSD), Bipolar Disorder (BD), Depressive Disorder (DD), Anxiety Disorder (AD), Attention-deficit/hyperactivity disorder (ADHD), and Other psychiatric and/or neurodevelopmental conditions.

Results: The cohort included 2799 adults with a first recorded diagnosis of autism between 2012 and 2017. Several psychiatric and/or neurodevelopmental conditions were recorded since 2002, including AD (77.5%), DD (58.0%), SSD (49.4%), BD (48.3%), and IDDs (33.2%). Results revealed 5 distinct types of TDs. Types 1 (63.8%), 2 (17.6%) and 3 (6%) represented individuals in younger age groups with similar characteristics but with very different sequences of diagnoses, characterized by mixed diagnoses in type 1, SSD and AD in Type 2, and IDDs, DD, AD, and ADHD in type 3. Types 4 and 5 (9.0% and 3.6%), representing middle-aged/older groups, displayed distinctive TDs associated with high healthcare use, almost entirely associated with SSD (Type 4) and BD (Type 5).

Conclusion: This study proposes a complementary examination of the multiple pathways to diagnosis experienced by adults, highlighting the need to address differential diagnosis and co-occurring psychiatric and neurodevelopmental conditions.

Keywords: Autism spectrum disorder; Healthcare use; Mental healthcare; Neurodevelopmental disorder; Psychiatric disorder; State sequence analysis.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: This study was approved by the Research Ethics Board Committee of the Université de Sherbrooke and by the Commission d'accès à l'information of Quebec. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Study cohort flow diagram. *The study cohort consists of patients diagnosed with ASD in adulthood (n = 2799), representing 28% of all patients diagnosed with ASD (n = 9882) between January 2012 and December 2017
Fig. 2
Fig. 2
a State Distribution Plots and b Sequence Index Plot of the typology of Trajectories of Diagnoses (TDs). State Distribution Plots show the distribution of states (proportion) for each trimester of follow-up (69 semesters between 2002 and 2017) while the Sequence Index Plots show the individual’s sequence of registered diagnoses
Fig. 3
Fig. 3
Mean number of days spent in each state by types of Trajectories of Diagnoses (TDs) during the 16-year follow-up period
See this image and copyright information in PMC

References

    1. Lewis LF. Identifying autism spectrum disorder in undiagnosed adults. Nurse Pract. 2018;43:14–8. - PubMed
    1. Lord C, Elsabbagh M, Baird G, Veenstra-Vanderweele J. Autism spectrum disorder. Lancet. 2018;392:508. Available from: https://pmc.ncbi.nlm.nih.gov/pmc/articles/PMC7398158/. [cited 2023 Dec 21]. - PMC - PubMed
    1. Rosen NE, Lord C, Volkmar FR. The Diagnosis of Autism: From Kanner to DSM-III to DSM-5 and Beyond. J Autism Dev Disord. 2021;51:4253–70. Available from: https://link.springer.com/article/10.1007/s10803-021-04904-1. [cited 2024 Jan 13]. - DOI - PMC - PubMed
    1. Fusar-Poli L, Brondino N, Politi P, Aguglia E. Missed diagnoses and misdiagnoses of adults with autism spectrum disorder. Eur Arch Psychiatry Clin Neurosci. 2022;272:187–98. Available from: https://pubmed.ncbi.nlm.nih.gov/32892291/. [cited 2023 Dec 5]. - PMC - PubMed
    1. Zeidan J, Fombonne E, Scorah J, Ibrahim A, Durkin MS, Saxena S, et al. Global prevalence of autism: A systematic review update. Autism Res. 2022;15:778–90. Available from: https://onlinelibrary.wiley.com/doi/full/10.1002/aur.2696. [cited 2023 Dec 20]. - DOI - PMC - PubMed

LinkOut - more resources