📄 psychiatry and clinical psychology

Adults who suspect they may be autistic or have ADHD show corresponding neurodevelopmental polygenic effects

This study demonstrates that adults who suspect they have autism or ADHD exhibit polygenic profiles and genetic correlations closely resembling those of diagnosed individuals, suggesting that their self-identification is biologically grounded and that differences in diagnosis rates are likely driven by factors beyond genetic predisposition, such as access to care and co-occurring mental health conditions.

Original authors: Alhadeff, A., Warrier, V., Zhao, Y., Perry, L., He, Y., Ma, Q., Baron-Cohen, S.

Published 2026-08-04

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CC BY 4.0

Original authors: Alhadeff, A., Warrier, V., Zhao, Y., Perry, L., He, Y., Ma, Q., Baron-Cohen, S.

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ⚕️ This is an AI-generated explanation of a preprint that has not been peer-reviewed. It is not medical advice. Do not make health decisions based on this content. Read full disclaimer

Imagine your brain is like a massive, bustling city. For a long time, scientists thought that if you didn't have a "city planner's permit" (a formal medical diagnosis) for certain conditions like Autism or ADHD, you were just living in a different neighborhood entirely. But lately, more and more adults are looking at their own lives and thinking, "Wait a minute, I think I might live in that Autism or ADHD neighborhood, even though I never got the permit." This has sparked a big debate: Are these adults actually part of the neurodevelopmental community, or are they just experiencing a mix of other common mental health struggles that look similar? To answer this, scientists use something called "polygenic scores." Think of these scores like a genetic weather forecast. Instead of looking at one single gene, they look at thousands of tiny genetic clues scattered across your DNA to see if the "genetic storm" for Autism or ADHD is brewing. If the forecast for someone who suspects they have a condition matches the forecast for someone who has a confirmed diagnosis, it suggests they are indeed part of the same genetic family.

This is exactly what a team of researchers from the University of Cambridge set out to investigate. They looked at data from over 150,000 adults in the UK Biobank, a giant database of health information. They split these people into three groups: those with a formal diagnosis, those who suspect they have Autism or ADHD but haven't been diagnosed, and those who don't suspect anything. They then ran a genetic check-up to see if the "suspect" group shared the same genetic blueprint as the "diagnosed" group.

The results were like finding a missing puzzle piece that fit perfectly. The study found that adults who suspect they are autistic or have ADHD carry genetic profiles that are almost identical to people who were diagnosed with the same conditions later in life. In fact, the genetic link between the "suspected" group and the "diagnosed" group was so strong that it was statistically indistinguishable from being the same thing. The researchers also checked if these "suspects" were just a random mix of other mental health issues, like anxiety or depression. The answer was no; their genetic makeup was specifically tied to Autism and ADHD, not a general jumble of other conditions.

However, there was a twist in the story. While the genetic blueprints were nearly the same, the lived experience was slightly different. The group with formal diagnoses tended to have higher rates of co-occurring mental health conditions and reported more severe daily struggles than the "suspected" group. It's as if the "suspected" group and the "diagnosed" group are driving the same model of car (the same genetic engine), but the "diagnosed" group is currently driving through a much stormier, more difficult terrain. Even among the "suspected" group, those who scored very high on trait questionnaires (like the Autism Spectrum Quotient) looked genetically and phenotypically very similar to the diagnosed group, though they still had slightly fewer co-occurring mental health issues.

The study suggests that the reason so many adults remain undiagnosed isn't because they are "faking it" or just have general anxiety. Instead, it seems that factors like the severity of their daily struggles, their access to healthcare, or their willingness to seek help might be the deciding factors in who gets the official "permit." The researchers conclude that the genetic evidence strongly supports the idea that adults who suspect they are neurodivergent are genuinely part of the Autism and ADHD communities, and that the current system might need to shift to prioritize support based on a person's current needs and struggles, rather than just waiting for a formal diagnosis to arrive.

Technical Summary: Adult Suspected Autism and ADHD Show Corresponding Neurodevelopmental Polygenic Effects

Problem Statement
There is a growing population of adults who suspect they have autism or Attention Deficit Hyperactivity Disorder (ADHD) without a formal diagnosis. While rates of self-identification and suspected diagnosis have risen due to increased awareness and broadening criteria, a critical clinical and policy question remains unresolved: does this self-suspicion reflect the genuine polygenic architecture of neurodevelopmental conditions diagnosed in childhood, or does it instead represent a heterogeneous mixture of other psychiatric conditions and subclinical traits? Previous phenotypic studies comparing self-identified and formally diagnosed adults have yielded inconsistent results regarding mental health comorbidities and trait severity, largely due to small sample sizes and convenience sampling. Furthermore, adult diagnostic assessments are complicated by recall bias and the unavailability of developmental informants, making it difficult to determine if adult self-identification captures the same underlying etiology as childhood diagnoses.

Methodology
This study utilized genetic and phenotypic data from over 150,000 adults in the UK Biobank. Participants were classified into three groups based on self-report: "No Diagnosis," "Suspected" (those who believe they may have the condition but lack a formal diagnosis), and "Diagnosed" (those with a formal medical diagnosis).

Sample Sizes: The study analyzed 154,926 participants for autism traits (AQ-50) and 161,623 for ADHD traits (SWAN). The "Suspected" groups comprised 6,797 individuals for autism and 3,611 for ADHD, while the "Diagnosed" groups were smaller (296 autism, 207 ADHD).
Genetic Analysis: The authors conducted Genome-Wide Association Studies (GWAS) for suspected autism and suspected ADHD. They calculated genetic correlations ( $r_g$ ) between these suspected groups and external GWAS of autism and ADHD, specifically stratifying by age at diagnosis (earlier vs. later for autism; childhood vs. adulthood for ADHD). They also assessed correlations with other psychiatric conditions (e.g., depression, anxiety, schizophrenia).
Polygenic Scores (PGS): The study calculated PGS for neurodevelopmental and psychiatric conditions in the UK Biobank participants. They compared PGS distributions across the three diagnostic groups (No, Suspected, Diagnosed) and examined gradients within the "Suspected" group based on trait severity scores (AQ-50 and SWAN).
Phenotypic Analysis: The authors compared rates of co-occurring psychiatric diagnoses and continuous trait scores (depression, anxiety, neurodevelopmental traits) across the groups using logistic and linear regression models, adjusting for age, sex, and genetic principal components.

Key Contributions and Results

Genetic Correlation with Corresponding Conditions: The genetic correlation between suspected autism and external autism GWAS was not statistically less than 1, indicating a strong genetic overlap. Crucially, the genetic correlation was significantly stronger with later-diagnosed autism than with earlier-diagnosed autism. Similarly, suspected ADHD showed the strongest genetic correlation with adulthood-diagnosed ADHD compared to childhood-diagnosed ADHD.
Specificity of Genetic Profile: Genetic correlations between suspected neurodevelopmental conditions and other psychiatric conditions (e.g., depression, anxiety) were low to moderate. When conditioning on the polygenic effects of other mental health conditions, the genetic overlap between suspected status and the corresponding neurodevelopmental condition remained significant.
Polygenic Score Similarity: Polygenic scores for the corresponding neurodevelopmental conditions were elevated in both the "Suspected" and "Diagnosed" groups relative to the "No Diagnosis" group. There was no statistically significant difference in mean PGS between the "Suspected" and "Diagnosed" groups for most conditions, suggesting that the underlying genetic burden is similar regardless of formal diagnosis status.
Phenotypic Differences: Despite genetic similarity, the "Diagnosed" group exhibited higher rates of co-occurring mental health conditions and higher neurodevelopmental trait scores compared to the "Suspected" group. The "Suspected" group showed an intermediate profile between the "No Diagnosis" and "Diagnosed" groups.
Dosage Effects within the Suspected Group: Within the "Suspected" group, both polygenic scores and the odds of co-occurring psychiatric diagnoses increased linearly with increasing neurodevelopmental trait scores. Individuals in the "Suspected" group who scored above standard clinical screening thresholds (e.g., AQ-50 > 32) had PGS profiles and psychiatric comorbidity rates that were minimally different from the "Diagnosed" group, particularly for ADHD.

Significance and Claims
The paper claims that adults who suspect they are autistic or have ADHD possess polygenic profiles that are statistically indistinguishable from those of individuals diagnosed with the condition later in life (adolescence or adulthood). The findings refute the hypothesis that adult self-identification is primarily a manifestation of unrelated psychiatric conditions. Instead, the study suggests that the "Suspected" group represents a genuine neurodevelopmental cohort with a genetic architecture similar to late-diagnosed individuals.

The authors argue that the divergence between the "Suspected" and "Diagnosed" groups is likely driven by factors other than genetic risk, such as lower levels of functional impairment, fewer co-occurring psychiatric conditions, or differences in help-seeking behaviors. Consequently, the paper advocates for a shift in clinical prioritization: diagnostic access and support should be based on current psychiatric burden and functional need rather than solely on referral order or the presence of a formal childhood diagnosis. The study supports prioritizing adults who suspect they are neurodivergent and score above screening thresholds, as they share the same underlying genetic predisposition as formally diagnosed individuals.

Limitations
The authors acknowledge several limitations: the UK Biobank is not fully representative of the general population and suffers from participation bias; the small number of formally diagnosed individuals limits statistical power for certain PGS analyses; and the genetic analyses were restricted to individuals of European ancestry, limiting generalizability to other populations.

Technical Summary: Adult Suspected Autism and ADHD Show Corresponding Neurodevelopmental Polygenic Effects

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