The German version of the Perceived Stress Scale – psychometric characteristics in a representative German community sample

Stress and its consequences on health has been a major research topic over the last decades. Psychological Stress is considered as a crucial factor in the onset, course and exacerbation of various diseases, e.g. depression, cardiovascular diseases, immune-related disorders, and it has been related to higher overall mortality [1–5]. Overall, perceived stress is linked to reduced life satisfaction [6, 7]. While there is agreement on the substantial impact of stress on health, the conceptualization and assessment of stress, however, have not been consistent. In line with different definitions, the concept of stress has been assessed from environmental, biological, and psychological perspectives [8]. Besides the environmental and biological approach, the psychological approach has focused on the person’s appraisal of the significance of the stressor (primary appraisal) and the individual coping abilities (secondary appraisal) within a person-environment transaction [9].

The Perceived Stress Scale (PSS) developed by Cohen, Kamarck and Mermelstein [10] is a well-established self-report measure based on the psychological conceptualization of stress. The scale assesses “the degree to which situations in one’s life are appraised as stressful” (p. 387; [10]). It measures the degree to which life has been experienced as unpredictable, uncontrollable and overloaded in the past month. Cohen and Williams [11] defined perceived stress as a unidimensional construct. As the questions are general in nature, the scale is considered broadly applicable for any population subgroup [12]. The original scale consists of 14 items (PSS-14), however, four items were dropped because of low factor loadings revealed by a principal components analysis. The shortened 10-item scale (PSS-10) showed slightly improved reliability (Cronbach alpha = .78 vs. Cronbach alpha = .75) and equivalent validity [11] and has therefore been recommended for epidemiological and clinical research [11, 13]. For settings with a limited time frame, e.g. telephone interviews, a brief 4-item version (PSS-4) has been developed [11]. However, a recent study exploring the structure of the PSS-4 in a community sample showed insufficient internal validity of the brief four-item version [14].

The PSS has been applied in diverse samples and in numerous studies investigating the association of perceived stress, for example, with human reproduction [15], coping profiles and health-related behavior [16], and cortisol level [17]. In a recent review evaluating the psychometric properties of the PSS across studies from different cultures and countries [13], Cronbach’s α for the 10-item version ranged from .78 to .91. Furthermore, the PSS demonstrated satisfactory test-retest reliability. Concerning construct validity, the PSS correlated moderately to strongly with depression and anxiety. In contrast to the theoretical one-dimensional conceptualization of perceived stress, findings of studies conducting factor analysis suggested and subsequently confirmed a two-factor structure for the PSS-10 across cultures. Regarding demographic characteristics, PSS scores were significantly lower in younger, married, and employed participants with higher income and fewer children. Interestingly, religion was not considered in the studies reviewed although religious coping has been a research topic in the investigation of psychological adjustment to stress [18, 19]. Although Lee [13] claimed that results for sex were inconsistent, the finding of higher perceived stress among women compared to men has been repeatedly replicated [20–22]. Women tend marginally to report more stressful life events [23] and suffer slightly more often from burn-out [24]. In a national US survey using the PSS-10 Cohen and Janicki-Deverts [25] found that women reported more perceived stress than men and stress increased with lower age, education and income. The inconsistent findings on age in this survey compared to the reviewed studies may have been due to different age compositions in the different samples. In regard to employment status, the level of stress was highest among unemployed participants, and lowest among retired persons. In contrast to this study, the majority of the studies reviewed by Lee [13] assessed college students or working populations. Therefore, the author stressed the importance of validating the PSS in representative samples and in various cultures in future studies.

Although the Perceived Stress Scale has become a well-established, world-wide used tool for assessing perceived stress since its introduction in 1983, the PSS-10 has not yet been validated in the German population. Therefore, the purposes of the present paper were (1) to assess the psychometric properties of the PSS-10 (reliability and validity, confirmatory factor analysis), (2) to compare demographic subgroups concerning general perceived stress, and (3) to provide norm values of a representative sample of the German population across the full age range from 14 to 95 years.

In line with previous research, we expected that perceived stress was associated with heightened distress (depression, anxiety, fatigue) and reduced quality of life. The association to procrastination, putting off intended action, as a personal trait consistently linked to stress [26], was also explored in the current study. We assumed that the scale was based on two latent factors. Additionally, PSS scores were hypothesized to be higher in younger age, females, unemployed and single participants.

This is the first study evaluating psychometrically the established PSS-10 in a representative German community sample covering a broad spectrum of demographic characteristics.

The results of the current study indicated good internal consistency and construct validity of the PSS-10. Perceived stress correlated strongly positively with depression, anxiety, fatigue, and procrastination and negatively with life satisfaction. Consistent with previous research [10, 13], the findings support the construct validity of the PSS. The suggested bi-dimensional model of the PSS-10 was confirmed by CFA consistent with previous studies (e.g. [36]). While Cohen and Williams [11] considered the distinction between the two factors as irrelevant and defined perceived stress as an unidimensional construct, Hewitt and colleagues [21] suggested that the scale covered two separate factors, measuring general stress and the ability to cope. Thus, Roberti and colleagues [37] labelled the first factor “perceived helplessness” and the second factor “perceived self-efficacy”. In line with the concept of primary and secondary appraisal within the process of coping with stressful events [9], the first factor emphasizes the individual’s reaction to stress, while the second factor refers to the self-assessed ability to cope with these stressors. In line with the multidimensional conceptualization of perceived stress, norm values are presented separately for both factors.

The level of general perceived stress differed between demographic groups. As psychological stress is associated with various diseases, the identification of highly stressed subpopulations is essential. As hypothesized, women reported more perceived stress than men. Perceived stress was highest among younger, unmarried and divorced, unemployed and less educated participants.

The reported higher level of stress among females is consistent with results of other studies in diverse countries [4, 20–22, 36, 38], although Cohen and collogues found no differences in their original study from 1983. Possible explanations for this finding have been discussed controversially taking social, biological and psychological hypotheses into account (e.g. [23, 39]). We found that women with higher income reported more stress than men with comparable salaries. Working women do not seem to feel more stressed at work per se, but are more likely exposed to non-work stressors compared to males [40]. Hence, from a social-psychological perspective, defined gender roles and expected demands in society may have an impact on perceived stress. However, the experience of stress seems to differ between sexes: women tend to feel emotionally exhausted, whereas men feel more depersonalized [24]. As the PSS includes no item assessing psychological stress as depersonalization, the level of stress among men might be underestimated in the current study. Therefore, further research is required to improve the understanding of the association between sex and perceived stress and its causes by measuring different ways of stress experiences.

In regard to age, in the current study younger participants felt significantly more stressed than their older counterparts in agreement with Cohen and Janicki-Devert’s [25] findings assessing the PSS in a national survey. A possible explanation for this result is provided by Carstensen's Socioemotional Selectivity Theory [41, 42]: Aging people prioritize to satisfy their social and emotional goals by focusing more on positive and less on negative emotions (e.g. reduced exposure to daily hassles [43]). The finding, that married persons feel less stressed, is consistent with evidence that social support reduced psychological stress (e.g. [44]). Regarding religion Muslim participants showed higher scores on the PSS-10 than Christians and participants unaffiliated with any religion. As a minority group, Muslims might be more exposed to social and psychological stressors including discrimination (e.g. [45, 46]) suggesting that rather the minority status than the denomination itself is linked to higher stress. In accordance with previous findings [25], and our hypotheses, the present study has demonstrated that perceived stress increased with lower education, income and employment status. This result may be explained by findings that unemployment, which is associated with lower income and lower education [47], may lead to declined psychological and physical well-being, and increased exposure to stressful events ([48]; see for a meta-analysis: [49]). In this context coping strategies and coping resources play a crucial role whose development and adaptive use can be impaired by socioeconomic status [50, 51]. Interestingly, the results of the present study suggested that people in training and students reported a slightly higher level of stress. Considering Lee’s [13] objection that the PSS has been mainly explored in students’ samples, this result underlines the importance to validate the scale in a representative sample in order to avoid misinterpretations. Moreover, in contrast to a former study [38], participants with children did not feel more stressed than their childless counterparts. This inconsistency may be due to the different samples as Lesage and colleagues assessed the PSS only in a working population. No differences were found regarding migration background. Interestingly, multiple regression revealed procrastination as a significant predictor for perceived stress giving further evidence for the association between procrastination and perceived stress [26, 52].

Finally, important limitations need to be considered. Data are limited to self-report which can lead to a response bias. Although significant differences were found, effect sizes were small. The effect of religious denomination is to be interpreted with caution due to a low number of Muslims in the sample. Because of the cross sectional study design the results do not allow drawing any causal conclusion. Therefore future longitudinal studies are needed to detect developments and changes of perceived stress over the time. However, to the best of our knowledge, the present study provided norm values for the PSS-10 basing on a large and randomly selected population, which so far only exists for the American [4, 11] and Swedish population [20].

In summary, the PSS-10 is a reliable and valid instrument for assessing perceived stress. The scale is easy to complete and can be administered in only a few minutes providing an economic measure for research and practice. It is important, however, to bear in mind that some subpopulations are more likely to experience stress as the present study showed. The dependency of the perceived stress level on socio-demographic variables, particularly age and sex, implies to use differentiated norm values, which are provided in this paper.