Hyperactivity in context: comparing actigraphy and informant ratings across the school week

Background Hyperactivity is a core symptom of childhood attention deficit hyperactivity disorder (ADHD), yet no population‐based studies have compared objective and subjective hyperactivity measures across the school day. Methods This study used data from N = 6,518 seven‐year‐olds in the Millennium Cohort Study. Physical activity was objectively measured using actigraphy every 15 min (Monday–Friday), and hyperactivity was assessed via parent and teacher Strengths and Difficulties Questionnaire ratings, analysed both as continuous (0–10) and binary (≥7; possible ADHD) scores. The association between actigraphy and hyperactivity were assessed via repeated ANOVAs throughout the day, accounting for sex and linear regressions during three school lessons (Lesson 1: 9.00–9.45 am Lesson 2: 11.00–11.45 am and Lesson 3: 1.15–2.00 pm). The effect sizes and standard errors were compared between morning and afternoon lessons. Results Continuous ratings from both parents and teachers were positively associated with objective activity across the school day (effect sizes = .015 and .008, respectively, both p FDR < .001). For teacher ratings, associations with continuous hyperactivity were significantly stronger in Lessons 2 and 3 than in Lesson 1 ( Z = 3.24, p FDR = .005; Z = 2.80, p FDR = .020, respectively). Conclusions These results illustrate how objective activity measurement can augment subjective assessments by capturing richer behavioural patterns in naturalistic educational settings.