The Zung Self-Rating Anxiety Scale (SAS)
THC Editorial Team January 24, 2022
- What Is the Zung Self-Rating Anxiety Scale (SAS)?
- What Does the Zung Self-Rating Anxiety Scale (SAS) Measure?
- Zung Self-Rating Anxiety Scale (SAS) Scoring Guidelines
- Zung Self-Rating Anxiety Scale (SAS) Validity and Reliability
What Is the Zung Self-Rating Anxiety Scale (SAS)?
Developed in 1971 by Dr. William Zung, a professor of psychiatry at Duke University, the Zung Self-Rating Anxiety Scale (SAS) is a self-administered, 20-item tool that helps screen people for anxiety symptoms—both psychological and somatic.1
Anxiety disorders are among the most prevalent mental health disorders in the general population of the United States. According to the World Health Organization (WHO), the global estimated lifetime prevalence and 12-month prevalence for any anxiety disorder is approximately 16% and 11%, respectively.2 By enabling health care providers and patients to identify and quantify anxiety levels, the SAS offers a critical tool to assist in the global attempts to understand anxiety levels among different populations.
What Does the Zung Self-Rating Anxiety Scale (SAS) Measure?
The SAS groups anxiety manifestations into cognitive, autonomic, motor, and central nervous system symptoms. Psychological and somatic items on the scale address negative experiences such as unwarranted fear and positive experiences such as the ability to breathe easily.3 For example, some items that refer to cognitive symptoms include “I feel afraid for no reason,” “I feel like I’m falling apart and going to pieces,” and “I get upset easily or feel panicky.” Items that refer to the motor and central nervous system symptoms include “My arms and legs shake and tremble,” “I am bothered by headaches, neck and back pain,” and “I feel weak and get tired easily.”
This scale screens for anxiety disorders and assesses whether someone should seek counseling for their anxiety.3 It should not be considered a replacement for a professional diagnosis, but it should help indicate how severe an individual’s symptoms may be. Although this scale shows high sensitivity and accurate severity ratings, the diagnoses given are based on the self-reported items rather than clinician-directed interviews. Thus, a mental health provider should always be consulted for a professional diagnosis.3
Zung Self-Rating Anxiety Scale (SAS) Scoring Guidelines
Each of the 20 items is answered on a four-point Likert scale ranging from 1 to 4:4
1 – A little of the time
2 – Some of the time
3 – A good part of the time
4 – Most of the time
A person’s score is calculated by adding up all the values selected. Higher scores indicate greater levels of anxiety. According to Zung, the total raw scores are converted to an anxiety index number using a conversion chart. The anxiety index numbers are interpreted as follows:5
Less than 45: Normal range
45–59: Mild to moderate anxiety levels
60–74: Marked to severe anxiety levels
75–80: Extreme anxiety levels
Zung Self-Rating Anxiety Scale (SAS) Validity and Reliability
Researchers assess the reliability and validity of their work in order to evaluate the quality of their research. Reliability refers to how consistently reproducible the results of their research are, meaning if something is reliable, it is statistically consistent. Validity refers to how well the results measure what they are intended to measure, meaning if findings are valid, they are statistically accurate.6
This scale has good psychometric properties, including good internal consistency, concurrent validity, convergent validity, and the ability to discriminate between clinical and nonclinical samples.3 There is some confusion regarding this scale’s cutoff values, or the values that indicate clinical levels. However, a great deal of research has been conducted to establish the recommended cutoff score further.7