*4.1. Preliminary Analyses*

To investigate any differences between groups in terms of the age and gender variables, we conducted a one-way ANOVA and a Chi-Squared test, respectively. No significant differences were found for the age variable (*F*(3, 453) = 0.58, *p* = 0.63). A Chi-Squared test showed a gender difference between groups (χ<sup>2</sup> (23, *N* = 454) = 12.8, *p* = 0.005). In particular, the Adjusted Standardized Residual (ASR), an index based on the difference between the observed counts and expected counts, suggests a significant number of males in the Quarantine group (ASR = 2.8) and a significant number of females in the Third group (ASR = 2.4). Considering the different distribution of male and females across groups (Table 2), we decided to conduct group comparison analyses differently for the male and female groups.

**Table 2.** Gender by group.


#### *4.2. Symptomatology*

As shown in Table 3, students' mean scores were below the pathological cut-off in every clinical dimension. However, it is noteworthy that the percentage of students who scored above the cut-off was considerable. For example, about 35.2% of students reported an elevated level of depressive symptomatology, and 32.5% of students reported obsessivecompulsive symptomatology. Moreover, about 28.6% of students presented an elevated level of psychological distress and 32.8% of students reported intensive symptomatology.

**Table 3.** Mean scores (*SD*) of SCL-90-R and percentage of pathological students.


SCL-90-R = Symptom Checklist-90-Revised; GSI = Global Severity Index; PSDI = Positive Symptom Distress Index; PST = Positive Symptom.

#### *4.3. Group Comparison*

A series of one-way ANOVAs were conducted to investigate differences between four female groups: BeforeCOVID vs. Quarantine vs. SecondPhase vs. ThirdPhase. As shown in Table 4, one-way ANOVA showed a significant difference between groups on obsessive-compulsive symptomatology (*F*(3, 385) = 3.51, *p* = 0.015, partial-η<sup>2</sup> = 0.03). A further post hoc test found that participants in the Quarantine group scored higher than participants in BeforeCOVID group (*p* = 0.005), in the SecondPhase group (*p* = 0.002) and in ThirdPhase group (*p* = 0.014). Results indicated a significant difference between groups in

interpersonal sensitivity symptoms (*F*(3, 385) = 5.11, *p* = 0.002, partial-η<sup>2</sup> = 0.04). A further post hoc test found that feelings of personal inadequacy and inferiority were significantly higher in the Quarantine group than in BeforeCOVID group (*p* < 0.001), in the SecondPhase group (*p* < 0.001) and in ThirdPhase group (*p* < 0.001). Analyses showed a significant difference between groups on depression symptomatology (*F*(3, 385) = 4.20, *p* = 0.006, partial-η<sup>2</sup> = 0.03). Post hoc analyses suggest that the level of depression in the Quarantine group was statistically higher than the BeforeCOVID group (*p* < 0.001), SecondPhase group (*p* = 0.006) and higher than the ThirdPhase group (*p* = 0.004). There was a statistically significant difference between groups in the paranoid ideation dimension as determined by one-way ANOVA (*F*(3, 385) = 3.76, *p* = 0.011, partial-η<sup>2</sup> = 0.03). Post hoc analyses suggest that hostility and suspiciousness thoughts in the Quarantine group were statistically higher than BeforeCOVID group (*p* = 0.014), SecondPhase group (*p* = 0.002) and statistically higher than ThirdPhase group (*p* = 0.003). Moreover, analysis showed significant differences in the psychoticism dimension (*F*(3, 385) = 3.96; *p* = 0.008, partial-η<sup>2</sup> = 0.03). A post hoc test revealed that withdrawal and isolation behaviours, in the Quarantine group were statistically higher than the BeforeCOVID group (*p* = 0.01), the SecondPhase group (*p* = 0.005) and statistically higher than the ThirdPhase group (*p* < 0.001). One-way-ANOVA showed a significant difference between groups on the level of psychological distress (*F*(3, 385) = 3.65, *p* = 0.013, partial-η<sup>2</sup> = 0.03). Post hoc analysis indicated that the level of overall psychological distress in the Quarantine group was significantly higher than the BeforeCOVID group (*p* = 0.004), SecondPhase group (*p* = 0.004) and ThirdPhase group (*p* = 0.004). Lastly, analysis showed a significant difference between groups on the number of self-reported symptoms (*F*(3, 385) = 4.41, *p* = 0.005, partial-η<sup>2</sup> = 0.03). Post hoc analyses indicate that the number of self-reported symptoms in the Quarantine group was statistically higher than the BeforeCOVID group (*p* < 0.001), SecondPhase group (*p* = 0.003) and statistically higher than the ThirdPhase group (*p* = 0.002). There were no statistically significant differences between group means as determined by one-way ANOVA in the other dimensions. See Figure S1 in Supplementary Materials for a graphic representation of descriptive analyses.

**Table 4.** Mean (*SD*) score by female groups; ANOVA analysis.


SCL-90-R = Symptom Checklist-90-Revised; GSI = Global Severity Index; PSDI = Positive Symptom Distress Index; PST = Positive Symptom.

A series of Kruskal–Wallis analyses were conducted to investigate differences between four male groups: BeforeCOVID vs. Quarantine vs. SecondPhase vs. ThirdPhase. As shown in Table 5, the results showed no significant differences between the male groups. See Figure S2 in Supplementary Materials for a graphic representation of descriptive analyses.


**Table 5.** Mean (*SD*) score by male groups; Kruskal–Wallis analysis.

SCL-90-R = Symptom Checklist-90-Revised; GSI = Global Severity Index; PSDI = Positive Symptom Distress Index; PST = Positive Symptom.
