Frequency and Length of Schizophrenia Admissions: Analysis by Icd-10 Defined Subtypes

The frequency and length of admissions over 50 years were analyzed in a sample of 10.268 schizophrenic patients according to ICD-10 subtypes of schizophrenia. The lowest yearly hospitalization frequencies during the risk period were observed in simple, catatonic, unspecified and hebephrenic schizophrenia. When the total sample was analyzed, unspecified schizophrenia exhibited a significantly higher length of hospitalization than paranoid and undifferentiated/other schizophrenia. However, after the exclusion of continuous hospitalizations, unspecified schizophrenia, in severe contrast, was identified as the subtype with lowest admission length. This indicates the need for further research in order to explore the homogeneity of that diagnostic category, i.e. whether unspecified schizophrenia encompasses two subgroups with significantly different courses. Despite the fact that paranoid schizophrenia is generally considered as having the best course and prognosis, this subtype did not have the lowest frequency, nor length of hospitalization. A weak, but significant, negative correlation was observed between admission rate and the length of hospitalization for the total sample, and particularly in the paranoid and residual schizophrenia subtypes. In conclusion, subtypes of schizophrenia differ both in hospitalization rate and length of admission. The introduction of additional factors such as age at onset, gender, subtype presented at initial course of disorder or subtype stability during further analyses could help to identify groups that are more homogenous in their course, prognosis, and, possibly, etiology.