*2.2. Sample Size*

The sample size was calculated using the single proportion equation in the Raosoft software package (Raosoft Inc., Seattle, WA, USA) [31] with a margin of error of five percent at the 95% confidence range. Based on a study published in Saudi Arabia the estimated prevalence of alexithymia was 49% [13]. The required sample size was approximately 296 students. The sample size was expanded due to a predicted lower response to an online questionnaire.

#### *2.3. Sampling Technique*

A stratified sampling technique was used to choose the participants. We used Google Forms and Excel sheets for data collection and entry. In addition, we sent the questionnaire via students' university email to the participants. Prior to being asked to provide consent to participate, each participant was briefed on the study's goal and objectives. Participants were also given the assurance that their replies to the questionnaire would remain anonymous. The participants were also told that they could withdraw from the study at any time and that it was not a requirement for their course.

#### *2.4. Survey*

The questionnaire (see Supplementary Materials) consisted of three parts: the first one being the demographics section, where participants were asked to identify their age, gender, smoking status, BMI, academic phase, marital status, income, and type of housing. They were then asked if they have a chronic disease and how often they engage in physical activities. The variables included in the statistical analysis were determined through the literature, and their applicability to the Saudi Arabian setting was assessed. The second part consisted of the Toronto Alexithymia Scale (TAS-20), which is used to assess the prevalence of alexithymia [32]. The TAS-20 is a self-report scale comprising 20 items that are rated using a five-point Likert scale where 1 = strongly disagree and 5 = strongly agree. The cut-off scores on the TAS-20 are ≤51 for the low end (meaning no alexithymia) and ≥61 for the high end (alexithymia). Scores between 52 and 60 indicate possible alexithymia. There is no relevant validation and adaptation research of this scale for the population of Saudi Arabia based on statistics. However, this scale has been utilized in a number of studies in Saudi Arabia and has shown that they had an acceptable level of internal consistency for the Saudi population [13,20,30,33]. We also found an acceptable level of internal consistency in this part of the questionnaire (Cronbach's alpha: 0.77). The third part consisted of the Patient Health Questionnaire-9 (PHQ-9), which is a self-administered questionnaire used to screen for depression and assess its severity. The items were scored on a four-point scale rated from nil (not at all) to three (nearly every day) [34]. As for the PHQ-9, the overall score was obtained by totaling all discrete scores for the items that ranged from 0–27 points. The PHQ-9 scales indicated that those who had a score of 0–4 were considered normal, 5–9 was mild depression, 10–14 was moderate depression, 15–19 was moderately severe, and 20–27 was severe depression. This scale was adapted and validated in the Saudi population [35–38].

### *2.5. Ethical Consideration*

All ethical considerations were assured before, during, and after conducting the study. Approval to conduct the study was obtained from the Institutional Review Board committee at the KKU (HAPO-06-B-001).

#### *2.6. Statistical Analysis*

The data were collected, reviewed, and then fed to the Statistical Package for Social Sciences version 21 (SPSS: An IBM Company). All statistical methods used were two-tailed with an alpha level of 0.05, considering significance if the *p*-value is less than or equal to 0.05. Descriptive analysis was conducted by prescribing frequency distribution and percentage for study variables including students' bio-demographic data, grade, Grade Point Average (GPA), medical data, TAS-20, and PHQ-9. Alexithymia and depression prevalence and severity were graphed. Crosstabulation for factors associated with alexithymia among medical students was determined with Pearson's chi-square test for significance and an exact probability test for small frequency distributions. A multiple logistic regression model was used to assess adjusted relationships with an odds ratio as effect size for relationships.

#### **3. Results**

#### *3.1. Particpitants Demographic Chractristics*

A total of 333 students were included. The students' ages ranged from 18 to 27 years with a mean age of 22.3 years old. A total of 215 (64.6%) students were in their clinical years, and 171 (51.4%) were females. A total of 290 (87.1%) were single. As for BMI, 80 (24%) complained of being overweight, 48 (14.4%) had class I obesity, 22 (6.6%) had class II obesity and 6 (1.8%) had class III obesity. A total of 94 (28.2%) students were smokers, and 108 (32.4%) exercised once weekly; however, 95 (28.5%) never exercised. A total of 67 (20.1%)

of students' parents were divorced. Ninety-one students (27.3%) had a monthly income of 10,000–15,000 Saudi Riyal (SAR), while 133 (39.9%) had a monthly income exceeding SAR 15,000. A total of 114 (34.2%) had chronic health problems (Table 1).


**Table 1.** Demographic data of medical students at King Khalid University, Saudi Arabia, 2022.

SAR = Saudi Riyal (SAR 1 = USD 3.75).
