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 pFDR < .001). For teacher ratings, associations with continuous hyperactivity were significantly stronger in Lessons 2 and 3 than in Lesson 1 (Z = 3.24, pFDR = .005; Z = 2.80, pFDR = .020, respectively). CONCLUSIONS: These results illustrate how objective activity measurement can augment subjective assessments by capturing richer behavioural patterns in naturalistic educational settings.