Tests and screenings
A series of tests that might help to determine the mental conditions with related symptoms and differentiate the case of substance abuse is mandatory for a proper diagnosis. The doctor will also request imaging screening such as MRI or CT scans to diagnose a patient with schizophrenia.
Moreover, there is a specialized criterion for the determination of schizophrenia which the American Psychiatric Association has been establishing. A mental health professional or a doctor uses the diagnostic and statistical manual of mental disorder i.e., DSM-5 according to the American Psychiatric Association.