What is the Perceived Stress Scale Questionnaire (PSS) and how does it work

The PSS asks patients to share how often stress-related thoughts or feelings occurred in the past month. For example, one item asks “In the last month, how often have you felt that you were unable to control the important things in your life?”

Adding up the responses on the PSS results in a total score, with higher scores indicating greater stress. In CBS Health’s implementation of the questionnaire, patients with scores from 14 to 25 are considered to have moderate stress, and scores above 27 indicate high perceived stress.

The PSS specifically asks about subjective symptoms, hence the “perceived” part of its name. Two patients may have had the same experiences or events happen to them, but some individuals may not perceive them as stressful, while others would—the PSS aims to capture that stress level rather than any particular experiences.

The strong reliability of the PSS has been demonstrated by several studies (see Lee, 2012), and validity has been established by showing that PSS scores predict a broad range of outcomes known to be associated with stress, such as mental health, psychosomatic symptoms, and health service utilization (see Cohen & Williamson, 1998, and Baik et al., 2019).

Scores on the PSS do not suggest a particular diagnosis or course of treatment, but are meant as an aid to quantify a patient’s level of perceived stress and measure improvement over time.