To diagnose a mental illness a doctor will consult a classification system, which lists all clinical characteristics also known as symptoms for a diagnosis to be made.
Having an agreed set of symptoms INCREASES RELIABILITY and DECREASES SUBJECTIVITY by psychiatrist.
Many systems but often lay used in UK is DSM V
Distinguishes between POSITIVE and NEGATIVE symptoms of schizo
POSITIVE = added behaviour like hallucinations which weren't present before
NEGATIVE = removed behaviour like loss of emotions,speech or motivation
In DSM V person is diagnosed with schizo in 4 stages:
1.SYMPTOMS show 2 or more one from 1-3
1.DELUSIONS incorrect beliefs
ppl out to get you — delusions of persecution
believe ur gr8 — delusions of grandeur