Perceived stress
Perceived stress is how stressful people judge their own lives to be. It is most often measured with the Perceived Stress Scale (PSS), which asks how far people appraise situations in their lives as uncontrollable and overloaded.
What it means in practice
Perceived stress is a self-report. The PSS measures the degree to which individuals appraise situations in their lives as excessively uncontrollable and overloaded [1]. One review defines stress itself as a person's interaction with their environment that is thought to threaten or affect their potential, resources and well-being [2].
The scale comes in a 14-item version (PSS-14) and a 10-item version (PSS-10) [2]. A meta-analytic factor analysis of 76 samples from 57 studies, with 28,632 people for the PSS-14 and 46,053 for the PSS-10, found that a correlated two-factor model best explained the scale's structure [2]. Internal consistency was high, and the scale showed strict measurement invariance across age and clinical status, meaning it behaved the same way in those groups [2].
A 2019 validation study noted there was no agreement on the scale's factor structure [1]. In 11,939 German adults, a model with one general and two specific factors fitted the PSS-10 [1]. It showed strong measurement invariance across gender and, in a second study, strong invariance over time [1].
Why it matters when reading nootropics research
The PSS is widely used, including to evaluate intervention effects in stress management studies [1]. When a supplement trial reports a change in perceived stress, check which version of the scale it used, since the 10-item and 14-item versions were analyzed as separate scales [2].
Because people rate themselves, blinding matters. Check whether participants could tell which group they were in and how the placebo group's scores moved. On NootropicsWork, perceived stress is one of the outcomes marked as subjective.
A trial might also report a stress hormone such as cortisol. That is a different kind of measure, taken from the body rather than from a questionnaire, and a change in one does not stand in for a change in the other.
References
- Reis D, Lehr D, Heber E, et al. The German Version of the Perceived Stress Scale (PSS-10): Evaluation of Dimensionality, Validity, and Measurement Invariance With Exploratory and Confirmatory Bifactor Modeling. Assessment. 2019.
- Yılmaz Koğar E, Koğar H. A systematic review and meta-analytic confirmatory factor analysis of the perceived stress scale (PSS-10 and PSS-14). Stress Health. 2024.