Manic-depressive psychosis in children younger than 15 years: a register-based investigation of 39 cases in Denmark.

Using a nationwide psychiatric case register covering a background population of 5.1 million inhabitants, 39 children (23 boys, 16 girls) were identified who got the diagnosis of manic-depressive psychosis between 1970 and 1986 before the age of 15. The frequency of manic-depressive psychosis in this child psychiatric population was 1.2%. The mean age for first-time admission with this diagnosis was 12.7 years. There was no sex difference. Twenty-six of the children got the diagnosis of manic-depressive psychosis during their first admission. Survival analysis was used to describe the prognosis and the diagnostic development of the group. As a whole, the group had a poor prognosis with many readmissions. The most common differential diagnoses were other types of psychosis in boys and oppositional and emotional disorders in girls.