**3. Results**

Table 2 presents the effect of measuring the frequency of the intensity of stress in the studied groups. The participants scored the PSS-10 scale from low (four raw points, three sten) to very high (35 raw points, 10 sten), and the mean result in the group approaching 19 raw points was within the range of six sten, indicating average severity of stress. The median for the stress level in the P1 group was 20 points and this result was four points higher than in the P2 group—this difference was statistically significant (Z = −2.665; *p* = 0.008). Differences in sten scores were also significant (Z = −2.768; *p* = 0.006). The stress level in the P1 group was higher than in the P2 group.


**Table 2.** Basic parameters of the distribution of stress measurement results in the study group (*n* = 188).

Then, the correlation between the intensity of pain and stress in the P1 group (*n* = 150) was analyzed. The measurement data presented in Table 3 indicate that with the increase in the severity of the sense of stress, the severity of headache (rho = 0.359; *p* < 0.001) and pain in the neck and girdle (rho = 0.240; *p* = 0.003) increased as well.

**Table 3.** Analysis of the correlation between the intensity of stress and the intensity of pain in the P1 group.


Table 4 presents the results of measurements of two variables: stress intensity (according to PSS10) and type D personality (according to DS14) among participants who reported one symptom of SS disorders. The analyses were carried out separately for the group of females and males. Males and females differ in this respect; females experiencing at least one SS symptom were characterized by a significantly higher level of stress and a type D personality (*p* < 0.05) compared to P2 group. Among males, these differences were not statistically significant (*p* > 0.05).

**Table 4.** Comparison of the mean results of the measurement of stress and type D personality among people suffering from one SS symptom, taking into account gender.


Table 5 summarizes the results of a hierarchical regression analysis explaining the intensity of stress experienced by the participants during the COVID-19 pandemic. In each of the five steps of the analysis, the model included successive groups of potential predictors of stress: coping strategies, occurrence of SS symptoms, pain intensity caused by these symptoms, type D personality index, and sociodemographic variables. Before the calculations were made, all data were standardized. It was assessed what percentage of the total variability (variance) in the observed stress intensity can be explained based on changes in individual potential predictors and which of the independent variables are statistically significant predictors. Ultimately, it was possible to explain more than half of the variability in the stress experienced by the participants during the pandemic.


**Table 5.** Hierarchical regression analysis explaining the intensity of stress among students during the pandemic.

(1) In the first step, the possibility to predict the level of stress severity during the pandemic by applying the strategies of coping with stress among the participants was assessed. Out of 14 strategies, four were significant predictors, which accounted for 33% of the stress variance.

The analysis showed that the higher the level of positive evaluation, the lower the level of stress. The other three strategies: discharging, taking psychoactive substances, and blaming oneself were positively related to the stress level.

(2) In the second step, after adding the presence of SS symptoms alone to the model, the explained variance increased to almost 37%, which was a statistically significant change (X2 (10.163) = 2.087; *p* = 0.002). The occurrence of headaches alone became a significant predictor of stress and caused its intensification. All remedial strategies detected in Model 1 as significant maintained their statistical significance (*p* < 0.05).

(3) In the third model, the intensity of the symptoms of the SS was added as a pool of potential predictors. Including them in the model did not significantly increase the percentage of the explained stress variance (X2 (4.159) = 1.468; *p* = 0.214; up to 38% of variance). The severity of pain in the neck and shoulder girdle was a significant predictor an increase in pain intensity in this area coexisted with a decrease in stress intensity. At the same time, after taking this predictor into account, the strategy of taking psychoactive substances and the occurrence of headaches became statistically insignificant.

(4) The fourth model included the results of measuring type D personality as a potential stress predictor, which resulted in a significant increase in the explained variance to 55% (X2 (1.158) = 64.591; *p* < 0.001). Of the temporary remedial strategies, only discharging and taking psychoactive substances remained relevant, and both previously diagnosed symptoms of SS lost their relevance. The result on the DS14 scale was the strongest predictor of stress, positively related to the explained variable. The increase in DS14 caused an increase in the level of stress.

(5) In the fifth model, additionally, a sociodemographic variable was introduced. The gender variable resulted in a significant increase in the explained variance of the stress intensity among students during the pandemic to 58% (X2 (3.155) = 4.109; *p* = 0.008). Among the implemented remedial strategies, the statistical significance was maintained by the discharging and taking psychoactive substances, and among the symptoms of SS, the increase in pain in the neck and shoulder girdle. The sum of type D personality indices was still the strongest predictor, while in the sociodemographic variable—gender—women were characterized by a greater intensity of stress than men.

Table 6 presents the results of the analysis of the correlation between the severity of stress and the styles of coping with it and DS14. It has been shown that the increase in type D personality manifestations was positively and moderately strongly associated with the overall intensity of stress (rho = 0.69; *p* < 0.001); participants with higher levels of stress were characterized by a greater number of type D personality symptoms. Moreover, this personality type was correlated with seven strategies for coping with stress. The severity of symptoms increased moderately with the increase in the tendency to blame oneself in problem situations (rho = 0.51; *p* < 0.001), and it also increased slightly with the increase in the tendency to denial (rho = 0.31; *p* < 0.001), discharging (rho = 0.27; *p* < 0.001), taking psychoactive substances (rho = 0.19; *p* = 0.009) and engaging in other activities (rho = 0.17; *p* = 0.019) and with a decrease in such constructive remedial strategies as positive reevaluation (rho = −0.29; *p* < 0.001) and sense of humor (rho = −0.19; *p* = 0.0010). The overall severity of stress moderately increased with the increase in tendency to blame oneself (rho = 0.46; *p* < 0.001) and weakly with the increase in ceasing activities (rho = 0.32; *p* < 0.001), discharging (rho = 0.31; *p* < 0.001), taking psychoactive substances (rho = 0.27; *p* < 0.001), denial (rho = 0.20; *p* = 0.007), engaging in other activities (rho = 0.15; *p* = 0.042), and with a decrease in the tendency to positively re-evaluate (rho = −0.27; *p* < 0.001), sense of humor (rho = −0.21; *p* = 0.004), active coping (rho = −0.17; *p* = 0.018), planning (rho = −0.16; *p* = 0.028), or seeking emotional support (rho = −0.14; *p* = 0.047).



*J. Clin. Med.* **2021** , *10*, 3872

\* *p* < 0.05; \*\* *p* < 0.01; \*\*\* *p* < 0.001.
