*2.3. Mental Health Well-Being*

For resilience assessment, two different questionnaires were used, that are based on different definitions of resilience in the scientific literature. Resilience can be defined as the ability of an individual to recover, or "bounce back" from a stressful situation [43–45]. Hence, Smith et al. introduced a Brief Resilience Scale (BRS), that consists of 6 different statements that could be answered through a 5-point Likert scale (ranged from "strongly disagree" to "strongly agree") [45]. Results of points 1–5 were assigned considering the response, and the total score is formed as an arithmetic mean of the answers of all 6 items. Therefore, the total score on BRS ranged from 1.00–5.00, with higher scores representing a higher resilience trait. Based on a final result, FPs were put in three different categories, with the result of 1.00–2.99 representing "low resilience", 3.00–4.30 "normal resilience", and 4.31–5.00 "high resilience". BRS is a widely used scale and already validated in different languages and population samples [46,47]. It was introduced and adapted to the Croatian language as well, with Cronbach's alpha coefficient of 0.82, indicating acceptable internal consistency [48]. In our study population, the calculated Cronbach's alpha coefficient was 0.84.

Furthermore, the second used questionnaire in our study that measures resilience is the Brief Resilience Coping Scale (BRCS), as resilience can be described as an ability to cope with stressful situations [49]. BRCS is translated and adapted to various languages and population samples as well, with acceptable measures of reliability [50,51]. It consists of 4 different statements to which participants expressed their agreement on 5-point Likert scale (ranging from "strongly disagree" to "strongly agree"). Points from 1 to 5 were assigned to each of the statements, with the total sum indicating the final score. Results from 4 to 13 represented "low resilient copers", from 14 to 16 "medium resilient copers" and from 17 to 20 "high resilient copers". Proper translation of BRCS was established with a back-translation technique by an English language expert. In our sample, Cronbach's alpha coefficient was 0.79, indicating adequate internal consistency.

Burnout symptoms were evaluated with the Oldenburg Burnout Inventory (OBI), a validated and widely used questionnaire from Demerouti and Bakker [52]. This scale is conceptualized to measure two different dimensions of burnout—emotional exhaustion (OBI-E) and cognitive and somatic expressions of disengagement (OBI-D) [53]. Each of the subscales consists of 8 different statements to which subjects expressed agreement with a 4-point Likert scale (from "strongly disagree" to "strongly agree"). Each item was given 1–4 points, with consideration to items that were reversibly scored, with an increasing score indicating a higher level of burnout symptoms. Thus, the score for each of the subscales could range from 8 to 32 points. For the purposes of this study, as we did not find universal cut-off values that would determine different OBI groups, respondents were divided into tertile groups based on their score. OBI was adapted into the Croatian language as well, with good reliability results [48], while in our sample, the Cronbach's alpha coefficient was 0.78 for the OBI-E subscale, and 0.85 for the OBI-D subscale, indicating good internal consistency as well.

The concept of satisfaction with life in our population was measured with the Satisfaction with Life Scale (SWLS), developed by Diener et al. [54]. It is one of the most commonly used and most reliable tools for this purpose [55]. It consists of 5 statements that describe different standards and expectations with life, to which participants subjectively respond using a 7-point Likert scale (from "strongly disagree" to "strongly agree"). Points from 1 to 7 were assigned to each answer, with higher scores indicating higher overall content with life. Furthermore, based on a final score, participants were put into 6 different groups: "extremely dissatisfied" (5–9 points), "dissatisfied" (10–14 points), "slightly below average" (15–19 points), "average" (20–24 points), "high score" (25–29 points) and "highly satisfied" (30–35 points). SWLS was translated using the back-translation technique, and it showed excellent internal consistency in our population sample (Cronbach's alpha coefficient was 0.91).

Job satisfaction levels were assessed with the commonly used and validated Warr– Cook–Wall scale, with confirmed good psychometric properties [56,57]. The scale originally consists of 15 items; however, in the current paper, an abbreviated 10-item version was used, adapted specifically to be more appropriate for FPs [57]. Participants can describe their satisfaction with different aspects of work through the 7-point Likert scale (from "extremely dissatisfied" to "extremely satisfied"), with the total score ranging from 10 to 70 points, and higher scores indicating better overall job satisfaction. Proper translation of the scale was ensured with the back-translation technique, with Cronbach's alpha coefficient of 0.86 indicating a good internal consistency measure.

Finally, physical, social and psychological aspects of a healthy lifestyle were assessed with the Fantastic Lifestyle Questionnaire (FLQ), an instrument developed originally by Wilson and Ciliska, and later adapted by the Canadian Society for Exercise Physiology to involve a more comprehensive view for each individual [58,59]. The questionnaire consists of a total of 25 questions that addresses the individual's behavior in the last month, that are distributed into 9 different domains (F: family/friends; A: activity; N: nutrition; T: tobacco/toxins; A: alcohol; S: sleep/seatbelt/stress/safe sex; T: type of behavior; I: insight; C: career). Most of the items have 5 possible answers on a Likert scale, while two of them are dichotomous. After calculation, the final score can range from 0 to 100 points, with a higher score indicating healthier lifestyle behavior. Finally, according to the results, subjects were distributed into 5 different groups (0–34 points "needs improvement"; 35–54 points "fair"; 55–69 points "good"; 70–84 "very good" and 85–100 "excellent"). The questionnaire was translated with the back-translation technique, and has shown good reliability in other studies [60], as well as in ours, where the Cronbach's alpha coefficient was 0.81.
