The association between likely ADHD and autism, and not being in employment, education, or training: a frequency-matched case-control study in working-age adults in the UK

Abstract Background To estimate the frequency of likely, often undiagnosed autism and attention deficit hyperactivity disorder (ADHD) in UK adults of working age (18-66 years) who are not in education, employment, or training (NEET), and to examine whether neurodivergent traits are associated with NEET status directly and indirectly via health burden and educational attainment. Design Frequency-matched online case-control study. Setting UK general population, recruited via online research platform Prolific. Participants Six hundred adults of working age (18-66 years); 300 NEET, 300 in education, employment, or training (EET) matched at the marginal level on age, sex assigned at birth, and ethnicity. Primary and secondary outcome measures Autistic traits (Ritvo Autism and Asperger Diagnostic Scale-14, RAADS 14) and ADHD traits (Adult ADHD Self Report Scale, ASRS 5) indexed likely autism and ADHD (cut off [≥]14 on each). Physical and mental health conditions were self reported and aggregated into composite indices of health burden. NEET status was the primary outcome; educational attainment and health burden were tested as parallel mediators of the association between neurodivergent traits and NEET status. Results NEET participants screened positive more frequently for likely autism (66.3% vs 49.0%; OR 2.05, 95% CI 1.48 to 2.85) and likely ADHD (34.3% vs 26.0%; OR 1.46, 95% CI 1.03 to 2.08) than EET participants, despite identical existing formal diagnosis rates. Physical (OR 2.00, 95% CI 1.38 to 2.90) and mental (OR 2.57, 95% CI 1.80 to 3.68) health conditions were also associated with higher odds of NEET status. In mediation analyses, neurodivergent traits predicted NEET status both directly (OR 1.33, 95% CI 1.13 to 1.68) and indirectly via greater health burden (indirect OR 1.13, 95% CI 1.02 to 1.35) and lower educational attainment (indirect OR 1.08, 95% CI 1.03 to 1.15). Conclusion NEET adults showed a marked excess of autism and ADHD traits, alongside elevated physical and mental health burden and lower educational attainment. Earlier recognition of neurodivergent traits, proactive provision of equitable requirements in education and employment, and integrated physical and mental health support may reduce NEET risk in this population. This has considerable implications for policy and practice in health, education, and wider society.