Prevalence of Attention-Deficit/Hyperactivity Disorder Across Gender and Sexual Identity Groups in Youth: A Whole-of-Population Study

PURPOSE: To estimate attention-deficit/hyperactivity disorder (ADHD) prevalence across gender identity, transgender status, and sexual identity using whole-population linked data in Aotearoa New Zealand (NZ). METHODS: A nationwide cohort study using the 2023 NZ Census linked to administrative health data within Stats NZ's Integrated Data Infrastructure. Individuals aged 5 to 24 years were included. ADHD was identified from lifetime diagnosis and treatment records. Modified Poisson regression models estimated adjusted incident rate ratios (IRRs) by gender, transgender status, and sexual identity. RESULTS: Among 1,266,456 individuals, 43,095 (3.4%) had ADHD. ADHD prevalence was higher among those identifying with another gender (10.3%) than males (4.6%) or females (2.0%), and among transgender (9.9%) than non-transgender individuals (3.4%). Among those aged 15 to 24 years, ADHD prevalence was higher in non-heterosexual (8.0%) than heterosexual individuals (3.6%). Adjusted analyses showed similarly elevated rates. CONCLUSION: ADHD prevalence was substantially higher among gender-diverse, transgender, and sexual diverse populations, highlighting the need for inclusive and equitable assessment and care pathways.