Children's Depression Inventory in Estonia. Single items and factor structure by age and gender.

The aim of study was to estimate the score of symptoms of depression with the Children's Depression Inventory (CDI) among Estonian schoolchildren aged 7-13-year-old, according to age and gender differences, and to identify the components in factor analysis characterising self-reported childhood symptoms of depression. The applicability of the CDI in 7-year-old children was also estimated. The number of subjects in the study was 725 (342 girls and 383 boys), and the mean age was 10.2 (SD 1.7). The mean total score of the CDI for the whole sample was 9.96 (SD = 6.3, range 0-39, median 9.0). The mean scores of symptoms of depression among children did not differ by gender or age. There were no significant differences in the CDI mean scores between 7-year-old compared to older schoolchildren in the present study. Factor analysis obtained five factors: anhedonia, ineffectiveness, negative self-esteem, negative mood and interpersonal problems. Significant gender and age differences were found: girls reported more symptoms of anhedonia and negative self-esteem, and boys reported more symptoms of ineffectiveness. Younger children reported more symptoms of anhedonia and ineffectiveness, and older children negative self-esteem. The study serves as baseline data before intervention of the EC project "European Alliance Against Depression".