• Diagnostic rates of routine hospital first and total admissions in various categories of functional mental illness in three strongly Schneider-oriented German psychiatric clinics over 40 years were examined. No matter how centers and categories were compared, statistically significant inconsistency was almost always found. Only first admissions for schizophrenia and mania in Munich and Heidelberg, as well as total schizophrenic admissions in Munich and Homburg/Saar, showed no significant diagnostic differences. However, from a practical point of view, actual percentage differences found in schizophrenia and mania were really not that great; indeed, rather similar diagnostic rates were apparent. This was in contrast to actual large percentage discrepancies shown between Munich on the one hand and Heidelberg and Homburg/Saar on the other with respect to manic-depressive illness and psychotic depression.
Koehler KG, Steigerwald F. Consistency of Kurt Schneider-Oriented Diagnosis Over 40 Years. Arch Gen Psychiatry. 1977;34(1):51–55. doi:10.1001/archpsyc.1977.01770130053005