Introduction: The purpose was to expand the understanding of schizophrenia development in children and adolescents. An age- and gender-specific analysis of children and adolescents diagnosed with schizophrenia (F20.xx) was performed. The analysis included calculation of incidence rates of schizophrenia, schizophrenia subtypes, and an account of occurrence of any registered psychiatric diagnoses prior to first schizophrenia diagnosis.
Material and methods: Patients aged 0-21 years diagnosed with schizophrenia (F20.xx) and registered in the Danish Psychiatric Central Research Register in 1994-2007 were included.
Results: The cohort consisted of 3,065 patients aged 6-21 years. Incidence rates vary with age and gender, and have been increasing in recent years. Boys have earlier onset and higher incidence rates than girls. The most common schizophrenia subtypes were paranoid (F20.0; 44.0%) and unspecified (F20.9; 28.7%). Three in every four patients had contact with the psychiatric hospital system prior to first schizophrenia diagnosis.
Conclusion: Schizophreniform symptomatology tends to overlap with other psychiatric disorders, and diagnostic stability is low. The diagnosis schizophrenia should be systematically included in diagnostic deliberations. Qualitative studies describing and analysing early psychopathology in children and adolescents with schizophrenia will improve the present knowledge.