Affective Dynamics and Mean Levels of Preschool Irritability and Sadness: Predictors of Children's Psychological Functioning Two Years Later.

Although irritability and sadness are cardinal symptoms of depression, they are also common in preschoolers. The daily experiences of these emotions are not well-understood during early childhood, yet may provide insight into identification of early depressive symptoms. The current longitudinal study examined daily mean levels and emotion dynamics of preschool-aged children's irritability and sadness and psychiatric outcomes in early school-age. Parents (n = 291) completed 14 consecutive daily diaries about their preschoolers' emotions. Two years later, parents (n = 164) completed a semi-structured clinical interview and questionnaires about their children's psychological functioning. Strong correlations between mean and dynamic measures (rs = 0.65-0.91) were identified. Preschoolers' mean daily levels and dynamics of irritability (variability, instability, inertia) and sadness (instability, inertia) predicted symptoms and impairment 2 years later. Sadness instability and inertia continued to predict difficulties after adjusting for mean daily sadness. Fine-grained daily measures of preschoolers' affect may be help identify children at-risk for psychological problems.