Issues surrounding the classification and diagnosis of Schzophrenia
Diagnosing a mental disorder is very different to diagnosing a physical disorder, as it cannot be seen in a biological sense. It's therefore more of a judgement call based on the psychiatriasts view on whether the patient meets the requirements of the classification system (CS) - it's more of a subjective procedure, there are issues to consider because of this.
Two issues are reliability and validity.
Reliability refers to how consistent comething is. In this case, whether the diagnosis is consistent or not. This can be consistency over time and consistency between doctors.
Kleitman (1961) identified 3 factors which may make the disgnosis of shizophrenia unreliable: