Time Changes in Teacher-Rated Emotional and Behavioural Problems in Children in 1999–2021

Background: research on secular trends provides important information for understanding and prediction of developmental processes in child mental health. Global stresses, such as the COVID-19 pandemic, superimpose on time trends, resulting in specific levels of child mental health in each gender and age group. Teacher reports are clinically significant and may substantially add to the existing evidence on time changes in common emotional and behavioural problems. The aim of study was to examine time changes in teacher-rated child emotional and behavioural problems using identical measures over a 23-year period, taking age, gender and the COVID-19 pandemic into account. Methods: in 1999-2021, teachers completed the Strengths and Difficulties Questionnaire (SDQ) designed for a quantitative assessment of common emotional and behavioural problems in children and adolescents. The study included 5987 children (48% male) from 2 to 18 years of age (mean age M = 9.9 years, SD = 3.9). Time changes were examined using Generalized Estimating Equations (GEE) to account for clustering, child gender and age, urbanization and the COVID-19 pandemic. Results: teachers reported progressively lower levels of child emotional and behavioural problems. Among boys, levels of hyperactivity-inattention, externalising and total mental health problems increased from 1999 to 2004, the subsequent decline was significantly larger among boys than girls. In 2020-2021, during the pandemic crisis, levels of all mental health problems were higher than expected from time trends. Teachers reported higher levels of emotional and behavioural problems and lower levels of prosocial behaviour in boys compared to girls. Levels of emotional problems increased with age among girls, and did not differ among boys. Conclusions: teacher reports showed generally positive time changes in child emotional and behavioural problems over the 23-year period. During the global stress linked to the COVID-19 pandemic, teachers reported higher levels of all mental health problems in children. Further studies are needed to identify possible causes of secular trends and to predict developmental pathways in child mental health.