The prevalence of disorders among preschoolers was lower than in previous studies from the USA. Comorbidity was frequent and there was a male preponderance in ADHD and depression at this early age. These results underscore the fact that the most common disorders of childhood can already be diagnosed in preschoolers. However, rates of disorder in Norway may be lower than in the USA.

In this study, we explored informant characteristics as determinants of parent–teacher disagreement on preschoolers’ psychosocial problems. Teacher characteristics were included in the analyses, in addition to child and parent factors. Psychosocial problems of 732 4-year olds from a Norwegian community sample were assessed by parents and teachers (CBCL-TRF). Furthermore, teachers reported on their education, experience and relationship to the child. Parental stress and psychopathology were also measured. Teachers rated children considerably lower than their parents did, especially on internalizing problems. When teachers rated more child problems, this was strongly associated with conflict in the teacher–child relationship, which predicted disagreement more than other factors. The highest agreement was on boys’ externalizing problems. Girls’ behavior was rated much lower by teachers than boys’ behavior compared to parents’ ratings. Possible teacher perception biases are discussed, such as teacher–child conflict, non-identification of internalizing problems, and same-gender child preference.

The validity of the Student-Teacher Relationship Scale (STRS) was examined in a preschool community sample (N = 925) using confirmatory factor analysis (CFA). Factorial invariance across genders was also investigated as was concurrent and discriminant validity. Indicators of validity were teacher-rated social competence, problem behavior, and mental health, as well as the children's score on the Peabody Picture Vocabulary Test. Results showed that the original three-dimensional model of the STRS was not satisfactorily confirmed. However, a slightly modified 25 items, 3-factor version of the STRS showed an acceptable fit. Model fit was acceptable for both boys and girls. The modified three-factor model evidenced good concurrent validity. The discriminant validity of the dependency versus the conflict subscale was somewhat unsatisfactory, mainly due to imperfections in the dependency subscale.