Schizophrenic disorders in childhood are rare. Only about 0.5 to 1% of all such disorders have their onset before age 9 and about 4% before age 14. In puberty and early adolescence, however, there is a marked increase in the frequency of such disorders. In childhood more boys seem to be affected, but during adolescence this difference seems to disappear. Possible etiological factors currently under discussion are genetic factors, neurointegrative deficits, attentional deficits, communication deficits and conspicuous premorbid features. With regard to the latter, the authors could show that positive and negative symptoms appear months or even years before the first manifestation of the disorder requiring inpatient treatment. From this perspective schizophrenic disorders in general and those with early onset in particular fit a dimensional model of illness better than a categorical one. In the development of preventive measures more attention to premorbid features is essential.