Clinical characteristics and risk factors for Kraepelinian subtype of schizophrenia: replication of previous findings and relation to summer birth.

The aims of the study were: (1) to replicate findings that patients with Kraepelinian schizophrenia constitute a distinct subgroup and (2) to examine the relationship between season of birth and the Kraepelinian subtype. Thirty-one Kraepelinian patients, defined on the basis of a longitudinal criterion--at least 5 years of continuous and complete dependence on others to maintain the basic necessities of life, including food, clothing and shelter--were compared with 279 non-Kraepelinian schizophrenic patients. All patients met ICD-10 criteria for schizophrenia and were evaluated with the Positive and Negative Syndrome Scale. Kraepelinian schizophrenic patients had more negative symptoms and were more disorganized than non-Kraepelinian patients. Positive and anxious-depressive symptoms did not differ between the two groups. Among Kraepelinian patients, there was an excess number of births in the month of July. These findings are consistent with previous reports that Kraepelinian patients could have a disease with an etiopathophysiology separate from that of other schizophrenic patients.