Diagnostic Tests for Schizophrenia

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 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
  • Positive
  • Cognitive

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 different items on the PANSS scale. Each gets ranked from 1 (absent) to 7 (extreme), giving a score between 30 to 210.

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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:

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 9 questions, including "How would you describe your mood over the last 2 weeks?" and "Have you felt that life wasn't worth living?"

WebMD Medical Reference Reviewed by Smitha Bhandari, MD on October 16, 2018

Sources

SOURCES:

Mayo Clinic: "Schizophrenia."

Journal of Addiction Research and Therapy: "An Assessment of Five (PANSS, SAPS, SANS, NSA-16, CGI-SCH) commonly used Symptoms Rating Scales in Schizophrenia and Comparison to Newer Scales (CAINS, BNSS)."

British Journal of Psychiatry Supplement: "Symptom rating scales and outcome in schizophrenia."

Schizophrenia Bulletin: "The positive and negative syndrome scale (PANSS) for schizophrenia."

Psychiatric University Hospital Zurich: "Scale for the Assessment of Negative Symptoms."

BMC Psychiatry: "Is There a Linear Relationship Between the Brief Psychiatric Rating Scale and the Clinical Global Impression-Schizophrenia Scale? A Retrospective Analysis."

Psychiatric Times: "BPRS Brief Psychiatric Rating Scale."

Psychiatry: "The Clinical Global Impressions Scale, Applying a Research Tool in Clinical Practice."

Schizophrenia Research: "Reliability and Validity of the Calgary Depression Scale for Schizophrenia (CDSS) in Youth at Clinical High Risk for Psychosis."

University of Calgary: "The Calgary Depression Scale for Schizophrenia."

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