Zung Self-Rating Anxiety Scale (SAS)

Abstract

The Zung Self-Rating Anxiety Scale (SAS) is a highly regarded 20-item self-report psychometric instrument designed to accurately quantify the severity of anxiety disorders in adult populations. Developed by William W.K. Zung in 1971, the scale utilizes a comprehensive approach, assessing symptomatic manifestations across four key domains: cognitive, autonomic, motor, and central nervous system functions. The SAS is routinely employed in clinical settings for both initial diagnosis and monitoring treatment efficacy, while also serving as a valuable screening tool for anxiety levels within diverse research cohorts.

Keywords

Anxiety, Zung Self-Rating Anxiety Scale, SAS, self-report, psychometrics, affective disorders, cognitive symptoms, somatic anxiety, psychological assessment, clinical screening.

Authors

William W.K. Zung

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Purpose

The primary objective of the Zung Self-Rating Anxiety Scale (SAS) is to offer a standardized and objective measure of the level of anxiety experienced by an individual. This tool is crucial for distinguishing between clinically significant levels of anxiety requiring intervention and normal, transient emotional reactions to stress. Its structured format contributes to reliable assessment across various clinical environments.

Furthermore, the SAS is extensively utilized for longitudinal monitoring, enabling clinicians and researchers to track fluctuations in anxiety severity over time. This capability is essential for evaluating the effectiveness of various therapeutic interventions, including pharmacological treatments and psychological therapies. The scale’s straightforward administration process ensures its high practicality for routine clinical screening and large-scale research studies.

Construct

The SAS is specifically designed to measure the psychological construct of anxiety severity. Unlike instruments that may narrowly focus on generalized worry or fear, the SAS captures a broad spectrum of symptomatic expressions, making it highly applicable to the multifaceted nature of generalized anxiety and panic disorders. The 20 items are meticulously structured to address symptoms across four core conceptual clusters originally identified by Zung:

• Cognitive Symptoms: Items relating to internal psychological distress, such as worry, fear, feeling easily upset, or experiencing panic.
• Autonomic Symptoms: Items concerning physical manifestations mediated by the autonomic nervous system, including physiological responses like heart rate acceleration or episodes of dizziness.
• Motor Symptoms: Items related to physical tension and restlessness, encompassing observable symptoms such as tremors, shaking, and general motor agitation.
• Central Nervous System Symptoms: Items addressing generalized systemic disturbances, including disruptions to sleep patterns and persistent feelings of physical weakness or fatigue.

This holistic methodology ensures that the scale provides a robust measure encompassing both the psychological distress and the somatic complaints frequently associated with clinical anxiety.

Validity

The Zung SAS has consistently demonstrated robust psychometric properties across numerous empirical investigations. Evidence of high Concurrent validity exists through strong correlations observed between the SAS scores and those obtained from other well-established anxiety measures, notably the Hamilton Anxiety Rating Scale (HARS) and the Taylor Manifest Anxiety Scale (TMAS).

The scale also exhibits strong criterion validity, successfully discriminating between patients who have received a clinical diagnosis of an anxiety disorder and non-anxious control groups. Additionally, studies focusing on specialized populations, such as adults with intellectual disabilities, have confirmed the scale’s utility and cross-contextual validity, supporting its widespread application in diverse clinical and research settings (Ramirez & Lukenbill, 2008).

Reliability

The reliability of the SAS is generally considered excellent, indicating strong internal consistency and temporal stability. Internal consistency, typically assessed using Cronbach’s alpha, frequently ranges from 0.85 to 0.93 in clinical populations. This high coefficient confirms that the 20 individual items cohere effectively in measuring a single underlying construct of anxiety severity.

Furthermore, Test-retest reliability studies conducted over short intervals have reported strong coefficients, confirming the measure’s stability over time. This suggests that provided the respondent’s actual state of anxiety does not significantly change, the scale will produce consistent results upon repeated administration.

Factor Analysis

While the Zung Self-Rating Anxiety Scale was originally conceptualized as a unidimensional instrument designed to yield a single, global anxiety score, subsequent explorations using factor analysis have often suggested a multi-factor structure. The most frequent finding supports a two-factor model, clearly separating symptoms into somatic anxiety (encompassing physical manifestations) and psychic anxiety (covering cognitive and emotional symptoms).

More complex factor analyses occasionally reveal four factors, which closely align with Zung’s initial conceptual framework (cognitive, autonomic, motor, and central nervous system symptoms). Despite these structural findings, the scale remains predominantly used in clinical practice by relying on the total raw score, which serves as a highly reliable and practical index of overall anxiety severity.

Instrument

Test Type: Self-Report Inventory

Format: 20 items rated on a 4-point Likert scale.

Language Available: English, Spanish, Arabic, and numerous other translations worldwide.

Population Group: Adults (Clinical and Non-Clinical)

Age Group: 18 years and older

Population Details: The scale is broadly applicable across diverse adult populations, including individuals with diagnosed psychiatric conditions, general medical patients, and non-clinical research samples.

Test Methodology: Respondents are required to rate how often they experience each symptom. The four response options are: A little of the time, Some of the time, Good part of the time, and Most of the time. Items are scored numerically from 1 to 4. To counteract potential response bias, ten items are worded positively and are subsequently reverse-scored during calculation. The total raw scores (ranging from 20 to 80) are often converted into an Anxiety Index score (typically multiplied by 1.25 to yield a 25-100 scale), although the raw score range is also widely used for clinical interpretation.

The standard scoring ranges for the raw score (20-80) are:

• 20-44 Normal Range
• 45-59 Mild to Moderate Anxiety Levels
• 60-74 Marked to Severe Anxiety Levels
• 75-80 Extreme Anxiety Levels

Keywords

Psychological assessment, anxiety measurement, William Zung, somatization, clinical screening, psychodiagnostics, self-assessment, Zung Self-Rating Anxiety Scale, psychometric properties.

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Authors

Author ORCID Identifier: N/A (Information not publicly available for the original author)

Affiliation Email addresses: N/A

Correspondence Address: N/A

Permissions & Fee and Test Year

The Zung Self-Rating Anxiety Scale (SAS) was first published in 1971. As a classical and foundational psychological instrument, it is generally considered to be widely available for both research and routine clinical use. While proper academic citation is always required, the scale is typically accessible without proprietary fees, although specific licensed versions or recent translations may be subject to licensing agreements.

Reference’s

• Zung, William W.K. (1971). A Rating Instrument for Anxiety Disorders. Psychosomatics, 12(6); 371-379.
• Ramirez, S., & Lukenbill, J. (2008). Psychometric Properties of the Zung Self-Rating Anxiety Scale for Adults with Intellectual Disabilities (SAS-ID). Journal of Developmental and Physical Disabilities, Vol. 20, No. 6, pp. 573-580.

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Items of the Zung Self-Rating Anxiety Scale (SAS)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

1. I feel more nervous and anxious than usual.
2. I feel afraid for no reason at all.
3. I get upset easily or feel panicky.
4. I feel like I’m falling apart and going to pieces.
5. I feel that everything is all right and nothing bad will happen.
6. My arms and legs shake and tremble.
7. I am bothered by headaches neck and back pain.
8. I feel weak and get tired easily.
9. I feel calm and can sit still easily.
10. I can feel my heart beating fast.
11. I am bothered by dizzy spells.
12. I have fainting spells or feel like it.
13. I can breathe in and out easily.
14. I get numbness and tingling in my fingers and toes.
15. I am bothered by stomach aches or indigestion.
16. I have to empty my bladder often.
17. My hands are usually dry and warm.
18. My face gets hot and blushes.
19. I fall asleep easily and get a good night’s rest.
20. I have nightmares.