Sex differences in ADHD symptoms point to possible barriers in diagnosis
Although ADHD is more often diagnosed in males during childhood, our new study shows that females report a larger difference in symptom severity between those with and without an ADHD diagnosis. Using data from large Norwegian population‑based and clinical cohorts, we highlight potential barriers for females in the recognition and diagnosis of ADHD.
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Attention‑deficit/hyperactivity disorder (ADHD) is more frequently diagnosed in males than in females, especially during childhood. However, research suggests that females may experience substantial ADHD‑related difficulties that are not always reflected in diagnostic rates. In this study, we examined sex differences in self‑reported ADHD symptoms across adolescence and adulthood using large Norwegian population‑based and clinical cohorts.
We analysed data from the Norwegian Mother, Father, and Child Cohort Study (MoBa), the youth@hordaland study, and the ADHD in Norwegian Adults (ANA) project, comprising more than 100,000 participants. ADHD symptom severity was measured using the Adult ADHD Self‑Report Scale Screener (ASRS‑6), allowing us to compare symptom levels in individuals with and without a self‑reported ADHD diagnosis across sex and age.
Across all cohorts, participants with ADHD reported higher symptom levels than those without ADHD. Symptom scores were highest among younger participants, particularly adolescent females. Importantly, the difference in symptom severity between individuals with and without an ADHD diagnosis was consistently larger among females than among males. This pattern was observed across both population‑based and clinical samples and was statistically significant in the adolescent and adult clinical cohorts.
These findings suggest that females who receive an ADHD diagnosis may, on average, report a greater symptom burden compared with females without ADHD than is observed among males. One possible interpretation is that females face higher thresholds for referral, assessment, or diagnosis, potentially because their symptoms are less likely to present as overt hyperactivity or disruptive behaviour.
Overall, our results indicate that sex differences in ADHD extend beyond prevalence rates and may reflect differences in symptom recognition and diagnostic practices. Increased awareness of these differences may help improve identification and access to care for individuals with ADHD, particularly females.