P: Different manuals are used to diagnose schizophrenia in different countries

E: For example, the DSM is commonly used in America, whereas the ICD is more commonly used in European countries.

E: As there are differences between the criteria in each manual, the diagnosis will be different depending on the country the patient is being assessed, therefore making the diagnosis unreliable.

P: Diagnosis can change over time as the criteria for the DSM and ICD are constantly updated

E: This could mean that people may no longer meet the criteria for diagnosis of schizophrenia, even though their symptoms haven't changed.

E: Therefore, someone diagnosed with schizophrenia in the past, may no longer receive the same diagnosis, resulting in low reliability

P: There can be gender bias present when diagnosing schizophrenia

E: For instance, men are far more likely to be diagnosed with schizophrenia than women. This may be because women are seen as better able to cope with their symptoms

E: Therefore, this suggests that the classification of schizophrenia lacks validity

P: There are issues with co-morbidity affecting the validity of research

E: For instance, Buckley found that 50% of schizophrenia patients also had a diagnosis of depression

E: This supports the idea that there are problems with validity as it could mean that the two disorders the patient is diagnosed with are one disorder

P: Diagnostic criteria are updated over time, affecting reliability.

E: Updates to the DSM and ICD mean that individuals previously diagnosed with schizophrenia may no longer meet the new criteria despite no change in symptoms.

E: This temporal inconsistency leads to low reliability in diagnosis.

P: Gender bias affects the validity of schizophrenia diagnoses.

E: Men are more frequently diagnosed with schizophrenia than women, possibly because women are seen as better able to cope with symptoms.

E: This suggests that the classification system may not validly reflect the true prevalence of schizophrenia across genders.

P: Co-morbidity challenges the validity of schizophrenia diagnoses.

E: Research by Buckley found that 50% of schizophrenia patients also had a diagnosis of depression.

E: This high rate of co-morbidity suggests that what is diagnosed as two separate disorders might be manifestations of a single disorder, questioning the validity of the diagnosis.

P: Symptom overlap further complicates the validity of schizophrenia diagnoses.

E: Schizophrenia and bipolar disorder share symptoms such as delusions and avolition.

E: This symptom overlap can lead to patients receiving different diagnoses depending on the clinician, undermining the validity of the classification system.