Temperament and sleep-wake behaviour from infancy to toddlerhood

Sleep-wake behaviours and temperament were examined longitudinally for trait stability and relationship to behavioural state regulation from infancy to early childhood. Subjects were 120 low-risk, full-term infants from a middle class sample. At 6 weeks, parents completed three consecutive days of the Baby's Day Diary which measures sleep, wake, fuss, feed and cry states and the Infant Characteristics Questionnaire. At 16 months, parents assessed sleep behaviours with the Sleep Habits Inventory and temperament with the Toddler Symptom Checklist. At 24 months, parents repeated 3 days of the Baby's Day Diary. Structural Equation Modelling was used to examine the cross-age hypotheses for sleep-wake and temperament associations. From early infancy to toddlerhood, sleep-wake behaviours and irritable temperament were notably stable but independent in this cohort.