DSK-5 needs only 1 positive symptom and 1 negative symptom.
Types of SZ
Paranoid SZ is characterised by powerful delusions and hallucinations
Hebephrenic SZ involves mainly negative symptoms.
Catatonic SZ involves disturbances in movement, leaving the sufferer immobile.
Positive Symptoms of SZ
Symptoms that are not present in non-schizophrenic individuals and include hallucinations and delusions.
Negative Symptoms
The loss of usual abilities and experiences, such as a volition and speech poverty.
Cheniaux et al. (2009)
100 patients were diagnosed by independent psychiatrists using both ICD-11 and DMS-5.
Results showed poor reliability,
Validity of SZ Diagnosis
Diagnosis suffers form a number of validity issues, including : Co-morbidity ; Symptom overlap ; Gender Bias ; Cultural Bias.
Co-Morbidity
The extent which two or more conditions occur together, calling into question the validity of diagnosis.
It could be that very severe depression can present as schizophrenia because the signs look a lot like it.
Buckley et al. (2009)
Found that around half of all patients diagnosed with SZ also had a diagnosis of depression. This factor is called into question the ability to tell the difference between the two conditions and diagnose accurately.
Symptom Overlap
Refers to the extent to which the symptoms of one disorder are also present in a different disorder.
E.G: SZ and Bipolar both include symptoms such as delusions and avolition.
Gender Bias SZ
A disproportionate number of men are diagnosed with SZ in comparison to women.
Cotton et al. (2009)
While it could be that men are more commonly diagnosed as they are genetically vulnerable, it may be that women are able to function better with the disorder than men.
Cultural Bias SZ
A higher number of African American and Afro-Caribbean descent are diagnosed with SZ compared to in Africa and the West Indies.
Some African cultures have different attitudes to some positive symptoms, such as hearing voices, which may be acceptable due to their believes with communicating to ancestors.
Escobar (2012)
Because the psychiatric profession is dominated by white people, psychiatrists might be over-interpreting symptoms and distrusting the honesty of black people for diagnosis.
Māori Culture
Some symptoms of schizophrenia are seen as acceptable in some cultures. For example, a study of 80 Māori people showed they deemed hearing voices to be completely normal.
Pinto et al (2017).
Investigate the risk of schizophrenia in Black Caribbean people and their descendants, as a meta-analysis of databases from 1950-2013.
Elevated incidence rates in Black Caribbean groups were found, present across all major psychotic disorders.
Copeland et al (1971).
An investigation into cultural variations in the diagnosis of schizophrenia.
In an experiment, Copeland (1971) gave 134 US and 194 British psychiatrists a description of a patient.
69% of the US psychiatrists diagnosed SZ but only 2% of the British ones gave the same diagnosis.
Diagnosis of SZ in not reliable between cultures.
Family Dysfunction
Family relations, communication patterns and though processes that do not support upbringing.
Theory of Expressed Emotion SZ
If family of high levels of negative expressed emotion cause greta deals of stress, this can be an initial onset factor for schizophrenia.
This is also correlated to relapses in SZ patients.