Four-year course of teacher-reported internalising, externalising and comorbid syndromes in preadolescent children.

The aim of this study was to elucidate the nature of comorbidity between internalising and externalising syndromes and its meaning in the course of these syndromes from 8 to 12 years of age in a school setting. The children in the cohort (N = 1320) were born in 1981. They were first surveyed in second grade (N = 1284) and followed up in sixth grade (N = 906). Teachers were the informants, and the study was carried out by means of a questionnaire. Data from both points of time were available on 861 subjects. The Rutter Teacher Questionnaire (RB2) measured behavioural and emotional symptoms at Time 1, and the Teacher Report Form (TRF) at Time 2. Comorbidity was more prevalent in boys than girls. Childhood comorbidity predicted externalising syndrome and comorbidity, but not internalising syndrome in early adolescence. It changed the course of boys' internalising syndromes to an externalising direction over time. The data suggest a gender difference in the pattern of comorbidity. When comorbidity was partialled out, it was very rare for internalising and externalising syndromes to develop into contrasting syndromes over time. The recovery rate for childhood comorbidity was poor. Special attention should be paid to making schools recognise and help these children.