Longitudinal relationship between maternal depression and infant temperament in a Japanese population.

To investigate the relationship between maternal depression and infant temperament in a Japanese population, a prospective questionnaire survey was administered in the postpartum period. Postnatal depression was assessed by Zung's (1965) Self-Rating Depression Scale on two occasions (5 days and 12 months after delivery). At 6 months and 18 months after birth, infant temperament was assessed using the Revised Infant Temperament Questionnaire (RITQ; Carey & McDevitt, 1978) and the Toddler Temperament Scale (TTS; Fullward, McDevitt, & Carey, 1984), respectively. Of the five temperamental dimensions of the RITQ and TTS, "rhythmicity" and "attention span and persistence" showed reciprocal relationships with postnatal depression. Unidirectional effects of maternal depression on infant temperament were found for "frustration tolerance" and "fear of strangers and strange situations."