The SDS is a well-established (Zung 1965) screening measure of adult depression severity that has been used in a variety of mental health areas including primary care, psychiatric, drug trials, and related clinical, institutional, and research settings. 

Number of items: 20

Procedure/Adminstration:  Self-report format. Respondents rate each symptoms “over the past several days” according to a 4-point scale from 1 (little or none of the time) to 4 (most or all of the time). (total possible of 80 points). Half of the items are worded positively and half are worded negatively.

How scored: A total score is obtained by summing the score of each item. Scores range from 20 to 80.

Interpretability: Higher scores indicate increased depressive symptoms. Scores over 50 suggest depression. Scores over 69 indicating severe depression

Acceptability: Sensitivity for correctly identifying when depression is present (using clinician ratings as gold standard) was 86% in SCI population. The SDS has been criticized due to its focus on symptom frequency rather than severity, though its intent is to assess the latter.

Languages: English, Chinese, Russian, Thai, Czech, Farsi, Indonesian, Lithuanian.

Usability: Easy to administer and score. The positive and negative item wording may be confusing for some individuals.

Time to administer: Less than 10 minutes.

Time to score: Time is unknown, but is likely minimal.

Training required: None

Availability: Measure widely available in PDF versions (with scoring key) at: http://healthnet.umassmed.edu/mhealth/ZungSelfRatedDepressionScale.pdf. An online version is available at: http://www.afraidtoask.com/depression/depressionzung.htm.

Equipment required: None

Summary:

• Since 1980, the SDS has been cited in approximately 25 investigations of adjustment to SCI.
• In some clinical applications the Beck Depression Inventory or the PHQ-9 may be preferable as they survey a two week period and include an item specific to suicidal ideation (this is consistent with DSM–IV criteria for major depression).

Psychometric Summary:

Note: TR= Test re-test; IC= Internal Consistency; Inter-O= Inter-observer; Intra-O= Intra-observer; SS= Sensitivity/Specificity.

Red light= A single study involving SCI subjects which has less than adequate findings of reliability, validity, and/or responsiveness.

Yellow light= A single study involving subjects with SCI which has adequate to excellent findings of reliability, validity, and/or responsiveness.

Green light= At least 2 studies involving subjects with SCI which have adequate to excellent findings of reliability, validity, and/or responsiveness.

N/a= No information.

*compared to the BSI, MEDS, and Ilfeld-PSI

References

• Tate D. Alcohol Use Among Spinal Cord Injured Patients. Am J Phys Med Rehabil 1993;72:175-183.
• Tate DG, Forcheimer M, Maynard F, Davidoff G, Dijkers M. Comparing Two Measures of Depression in Spinal Cord Injury. Rehabil Psychol 1993;38:53-61.
• Zung WWK. A self-rating depression scale. Arch Gen Psychiatry 1965;12:63-70.