A simple finger prick or cheek swab can't show whether you or someone you know has schizophrenia. Instead, your doctor will likely talk to you about your symptoms and rule out other disorders before they make a diagnosis. But there are also tests that help figure out how severe your symptoms are and point the way to the right treatment.
Your doctor may refer you to a licensed mental health professional (often a psychiatrist) for a psychological evaluation. First, they’ll make sure you don’t have any medical problems.
Your doctor will also ask you, your family, or both about your symptoms and psychiatric history.
Your family members or friends can help by giving the doctor a detailed history and information about things like:
- Changes in behavior
- Previous level of social functioning
- History of mental illness in the family
- Past medical and psychiatric problems
- Allergies (to foods and medications)
- Previous psychiatrists and other doctors.
A history of hospitalizations is also helpful. Your doctor can get the records at these facilities and review them.
Ruling Out Other Issues
Certain neurological disorders can sometimes cause symptoms that look like schizophrenia, such as:
- Brain tumors
- Endocrine and metabolic problems
- Infectious diseases
- Autoimmune conditions involving the central nervous system
Your doctor will do a physical exam. You might also need tests, sometimes including brain imaging techniques such as a CT scan or MRI of the brain.
Generally, lab results and imaging studies are normal in people who have schizophrenia. If you have a certain behavior as part of a mental disorder, such as drinking too much water, this might show up as a metabolic problem in your lab results.
Your doctor will look at whether your symptoms are from schizophrenia or if they could be caused by medications you’re taking.
Many drugs can trigger psychotic symptoms, including
- Certain over-the-counter and prescription drugs
A toxicology screen can help your doctor see if any substances in your body could have led to your psychotic symptoms. Symptoms can happen when you’re intoxicated and sometimes during withdrawal. If you’re dealing with substance abuse, your doctor can help figure out if the drug use is the reason for your psychotic symptoms or is simply another factor.
Some drugs can trigger a weakened immune response, which shows up as a low number of white blood cells.
Your doctor can also use psychological testing to further explore the symptoms of schizophrenia. These tests can include:
- Cognitive testing
- Personality testing
- Open-ended or projective testing such as the Rorschach (inkblot) test
Your doctor may prefer one specific test or use a combination of them. There's some overlap in what each test measures.
In general, the tests try to gauge how intensely your life is affected by three types of schizophrenia symptoms:
Negative symptoms are losses of normal function that cause problems such as flat emotions or expressions. Positive symptoms are feelings or behaviors that are normally not present, like psychotic symptoms that show some kind of break with reality. Cognitive symptoms include effects on your memory and attention.
For some of the tests, your doctor may talk with you for up to an hour and ask you specific questions about your symptoms. Other tests involve a few brief questions, and you may not even know that a test is going on.
Your doctor may use the results to decide if treatment can help, whether the therapy you get now needs to be changed, and whether your disease is getting better or worse.
Positive and Negative Syndrome Scale (PANSS)
This test has a reputation as the "gold standard" for measuring how well your treatment is working. Your doctor may use the PANSS test more than once over a period of time to check if a drug or therapy has made a real improvement in your symptoms.
For the PANSS test, your doctor will interview you for about 30 to 40 minutes. They'll also ask your family members or caregivers about your behavior.
In the first section of the test, your doctor will ask about your medical history and symptoms. In the second part, you may get questions that try to find out how severe your symptoms are. For instance, your doctor may ask things like, "How do you compare to the average person?" and "Do you have special or unusual powers?"
In the third section of the interview, focused questions like "How are a train and bus alike?" check to see how well you can reason. You may also get other questions about mood.
Based on your answers and your doctor's observation of your behavior, they'll give you a score on 30 items on the PANSS scale. Each item gets ranked from 1 (absent) to 7 (extreme), giving a score between 30 and 210.
SANS and SAPS Tests
These two tests analyze the effects of positive and negative symptoms.
SANS stands for Scale for the Assessment of Negative Symptoms. It measures 25 negative symptoms of schizophrenia, including:
- Lack of facial expressions
- Social inattentiveness
- Lack of interests and relationships
The full name of the SAPS test is Scale for the Assessment of Positive Symptoms. It checks 34 positive symptoms, including:
- Hallucinations (seeing or hearing things that aren't there)
- Delusions (strong belief in things that aren't true)
In both scales, each symptom is scored from 1 (none) to 5 (severe).
Brief Psychiatric Rating Scale (BPRS)
It's one of the most common tests that psychiatrists use when they want to check how severe someone's schizophrenia is.
The test looks at 18 symptoms or behaviors, such as hostility, disorientation, and hallucination. It ranks each on a scale of 1 (not present) to 7 (extremely severe).
The scores are based on a 20- to 30-minute conversation that your doctor has with you, your family members, or other caregivers.
Clinical Global Impression-Schizophrenia (CGI-SCH)
Doctors have adapted this test for people with schizophrenia from the more general Clinical Global Impression score, which is used to diagnose other psychiatric illnesses.
Like the PANSS test, doctors mostly use CGI-SCH when they want to see how well a schizophrenia treatment is working, either for one person or a group of people who are in a clinical trial.
The CGI-SCH measures two things:
- How severe your schizophrenia is
- How much the symptoms have changed since your last checkup
Each result is measured on a scale of 1 to 7, with 7 being the more severe form of schizophrenia or the greatest increase in schizophrenia symptoms.
While other tests involve a long interview with set questions, the CGI-SCH can be calculated by a psychiatrist in just a few minutes. The appointment includes questions about your symptoms over the previous 7 days.
Calgary Depression Scale for Schizophrenia
Doctors use this test to check you for symptoms of depression that could affect your daily life or might even lead you to have thoughts of suicide.
The scale relies on the answers to just nine questions, including "How would you describe your mood over the last 2 weeks?" and "Have you felt that life wasn't worth living?"