How does the doctor go about diagnosing schizophrenia?
The diagnosis of schizophrenia is based on the clinical pattern of the symptoms. There is no blood test, lab test or radiological investigation like a brain scan which is needed to confirm the diagnosis of schizophrenia.
The psychiatrist will usually make the diagnosis from the history and further directed questioning to ellicit the typical signs. The physical examination, blood tests and brain scans are done to exclude a treatable cause of the psychosis. Urine drug screens are needed to exclude illicit drugs.
An EEG (electro encephalogram) is done to exclude a seizure disorder (epilepsy). It is usually done if the presentation is atypical.
The typical clinical picture is usually one of chronic changes in behaviour from what was normal for the patient. A sudden acute change in behaviour or personality should alert the clinician to a physical cause for the symptoms.
There is a long list of possible diagnoses which include substance abuse, cancer, endocrine disorders such as thyroid and adrenal glands, nutritional and vitamin deficiency disorders, organ (liver, kidney) failure, chronic alcohol abuse, connective tissue inflammatory disorders, and vasculitis (inflammation of blood vessels.Further considerations are still needed in diagnosing schizophrenia. Neurological disordes such as a seizure disorder, Huntington Disease, multiple sclerosis, dementia and Brain tumours, brain abscesses, and brian strokes must be excluded. Heavy metal intoxication can also lead to psychosis.
Important infective causes to exclude are neurosyphilis and HIV.
Other psychiatric disordes such as Bipolar Disorder also need to be considered.