DASS-21: Depression Anxiety Stress Scales

What is the DASS-21?

The DASS-21 is a 21-item self-report questionnaire developed by Sydney H. Lovibond and Peter F. Lovibond at the University of New South Wales. It measures three related but distinct negative emotional states: depression, anxiety, and stress, with 7 items dedicated to each subscale.

The key advantage of the DASS-21 is its ability to differentiate between depression, anxiety, and stress within a single brief instrument. In clinical practice, these conditions frequently co-occur, and the DASS-21 helps clinicians identify which dimensions are most elevated for each client rather than relying on separate screening tools for each condition.

The DASS-21 is freely available for clinical and research use with no licensing requirements. It takes approximately 5 to 10 minutes to complete and has been validated across many languages and cultural contexts.

DASS-21 Scoring

Each item is rated on a 4-point scale from 0 (did not apply to me at all) to 3 (applied to me very much or most of the time), based on the past week. Raw subscale scores (sum of 7 items each) are multiplied by 2 to enable comparison with the full 42-item DASS normative data.

All scores shown above are after doubling the raw subscale totals (raw score × 2). This is the standard scoring convention for the DASS-21.

Clinical Applications

The DASS-21 is particularly valuable in settings where comorbidity between depression and anxiety is common, which describes the majority of outpatient therapy caseloads. Rather than administering separate instruments like the PHQ-9 and GAD-7, a single DASS-21 administration provides scores across all three dimensions simultaneously.

The three-subscale structure helps clinicians identify the primary treatment target. A client presenting with elevated depression and stress but normal anxiety scores may benefit from a different treatment approach than one with elevated anxiety and stress but normal depression. The DASS-21 makes these differential profiles visible in a way that single-construct measures cannot.

When administered repeatedly, the DASS-21 tracks treatment response across all three dimensions. This is especially useful when treating conditions where improvement in one area (e.g., depression) may unmask or coexist with continued elevation in another (e.g., stress).

Reliability & Validity

The DASS-21 demonstrates excellent internal consistency across all three subscales: Depression (Cronbach's alpha = 0.94), Anxiety (alpha = 0.87), and Stress (alpha = 0.91). Good discriminant validity between the three subscales supports their use as distinct clinical dimensions rather than a single composite.

The measure has been validated in clinical, non-clinical, and community populations across dozens of languages. Factor analyses consistently support the three-factor structure, confirming that the subscales measure meaningfully different constructs.