Sociodemographic form: Participants provided information on age, education, marital status, employment, income, smoking and alcohol use, emotional eating and weight loss product use.

Body Mass Index (BMI): Height and weight were measured using a calibrated scale and stadiometer. BMI was calculated as weight (kg) divided by height squared (m²).

Beck Depression Inventory (BDI): This 21-item scale assesses depression severity, with higher scores indicating greater depressive symptoms. It has been validated in Turkish populations [21].

Rosenberg Self-Esteem Scale (RSES): The 10-item self-esteem subscale of the RSES was used to evaluate self-esteem levels [22, 23]. The Rosenberg Self-Esteem Scale (RSES) is a Likert-type self-assessment tool measuring self-esteem, with response options ranging from “strongly agree” to “strongly disagree”. While the full scale consists of 63 items across 12 subscales, the 10-item self-esteem subscale is commonly used in research [23]. Higher scores indicate greater self-esteem. This study utilized the 10-item self-esteem subscale.

Body Satisfaction Scale (BSS): The Body Satisfaction Scale (BSS), developed by Berscheid et al. (1973) [24], was adapted to Turkish by Gökdoğan (1988) [25]. BSS was adapted with cultural considerations, ensuring validity through expert review and reliability via test-retest (r = 0.88). It includes 25 items for females and 26 for males, rated on a 5-point Likert scale from “extremely satisfied” to “not satisfied at all”. The scale assesses overall body appearance, face, body parts, and torso, with higher scores indicating greater body satisfaction. This study used the total BSS score to measure body satisfaction.

Obesity-Related Problems Scale (OP-S): The Obesity-Related Problems Scale (OP-S) was developed based on the Health-Related Quality of Life (HRQoL) scale to assess the impact of psychosocial functioning on the quality of life in individuals with obesity [20]. The OP-S consists of 8 items that assess the extent to which individuals feel burdened by their weight in various social situations. Scores range from 8 to 32 and are standardized (0–100). Higher scores indicate greater psychosocial impairment, categorized as mild (40), moderate (40–59), or severe ($\ge$60). In this study, the total OP-S score was calculated and converted into the OP-S-S score using the formula. The Turkish version of the OP-S used in this study was based on a previously conducted validity and reliability study by Polat et al. [26] (2014). In this adaptation study, the scale demonstrated good internal consistency (Cronbach’s $\alpha$ = 0.82) and a two-factor structure (social and psychological). Item-total correlations were within acceptable limits, and construct validity was supported by significant associations with measures of depression, body image, and psychological well-being.

Eating Disorder Examination Questionnaire (EDE-Q): The EDE-Q, developed by Fairburn and Cooper in 1993, is a self-report scale. Its Turkish validity and reliability were established by Yucel et al. [27] in 2011. A score of 4 or higher on any subscale is considered indicative of an eating disorder. In this study, participants with a score of 4 or higher were considered at risk for a probable eating disorder based on screening criteria, consistent with previous validation study [28].

All psychometric instruments used in this study had previously undergone Turkish validation and have demonstrated acceptable to excellent internal consistency. Reported Cronbach’s alpha coefficients from Turkish validation studies are as follows: BDI, $\alpha$ = 0.80–0.85 [21]; RSES, $\alpha$ = 0.76 [22]; BSS, $\alpha$ = 0.86 [29]; Eating Disorder Examination Questionnaire (EDE-Q), $\alpha$ = 0.90 [27]; and OP-S, $\alpha$ = 0.84 [20]. These coefficients support the reliability of the instruments used in the current study.

Participants completed self-report measures during their preoperative psychiatric evaluation. Of the 175 individuals approached, 11 declined to participate, and one withdrew after opting out of surgery. Data were analyzed using correlation and regression analyses to identify psychosocial predictors of preoperative functioning.

All statistical analyses were conducted using IBM SPSS Statistics for Windows, (Version 22.0; IBM Corp., Chicago, IL, USA). Descriptive statistics were used to summarize sociodemographic and clinical characteristics. Continuous variables are reported as means and standard deviations (SD), and categorical variables as frequencies and percentages. The assumption of normality was assessed for all continuous variables using the Shapiro–Wilk test. The results indicated that the distributions of key continuous measures, including the Obesity-Related Problems Scale standardized score (W = 0.983, p = 0.051) and Rosenberg Self-Esteem Scale (W = 0.987, p = 0.084), did not significantly deviate from normality. However, BDI scores significantly deviated from normality (W = 0.953, p 0.001). However, BDI scores significantly deviated from normality (W = 0.953, p 0.001). Despite this, parametric analyses were retained due to the sufficiently large sample size (n = 175) and the robustness of these methods to moderate deviations from normality. Given that the distribution of BDI scores deviated from normality, Spearman correlation was additionally performed as a non-parametric alternative. Furthermore, to assess the robustness of the Pearson correlation coefficients, a bootstrap analysis with 1000 samples was conducted. The results confirmed the reliability of the Pearson correlation between BDI and OP-S scores (mean r = 0.30, 95% CI: 0.19 to 0.41). Associations between OP-S subgroups and categorical sociodemographic and behavioral variables (e.g., gender, marital status, obesity classification) were examined using Pearson’s chi-square test. For the obesity classification variable, chi-square assumptions were violated ($>$20% of expected cell frequencies 5); therefore, Fisher’s exact test with Monte Carlo simulation (10,000 replications) was applied. For all other categorical comparisons, assumptions for Pearson’s chi-square test were met, with no expected frequencies below 1 and overall expected counts sufficient for valid interpretation given the total sample size (N = 175). The corresponding test statistics are reported in the Results section. Pearson correlation coefficients were calculated to explore bivariate associations among psychosocial functioning (OP-S standardized scores), depressive symptom severity, self-esteem, body satisfaction, and eating disorder symptoms. A multiple linear regression analysis was conducted to identify independent predictors of psychosocial functioning. Variables entered into the model included depressive symptom scores (BDI), self-esteem (RSES), body satisfaction (BSS), eating disorder symptoms (EDE-Q), BMI, and gender. A backward stepwise regression was also performed to assess the stability and parsimony of the model. All regression assumptions, including linearity, homoscedasticity, independence of residuals, and absence of multicollinearity, were examined. The level of significance was set at $\alpha$ = 0.05, and all p-values are reported to three decimal places. Analyses were two-tailed. To evaluate multicollinearity among predictors in the regression model, variance inflation factors (VIFs) were calculated. Furthermore, Harman’s single-factor test was performed to assess common method bias due to the use of self-report measures, using an unrotated principal component analysis.

The analysis of psychosocial functioning, as measured by the OP-S, revealed that the average score among participants indicated a moderate level of psychosocial impairment. This finding suggests that while individuals seeking bariatric surgery experience notable challenges related to their psychosocial well-being, the severity of impairment may vary significantly across different patients.

A previous study examining the psychosocial consequences of obesity and the impact of bariatric surgery on quality of life have reported inconsistent findings. Previous research has yielded results that align with the present study, demonstrating moderate impairments in psychosocial functioning and quality of life before surgery [30]. However, another study has indicated a more pronounced decline in psychosocial well-being, suggesting that individuals with severe obesity may experience greater psychosocial distress and functional impairments than observed in the current sample [31]. These discrepancies may stem from variations in quality of life measures and differences in assessed subdomains.

The analysis of depressive symptoms among study participants, as measured by the Beck Depression Inventory (BDI), indicated that the average score fell within the range typically associated with mild depressive symptomatology based on established cut-off points for the scale. This finding aligns with previous research indicating that depressive symptoms are relatively common among bariatric surgery candidates, with mild symptoms being among the most frequently reported [32]. The consistency of our results with the existing literature further supports the view that elevated levels of depressive symptoms are frequently present among individuals undergoing evaluation for bariatric surgery. Given the high rates of psychiatric comorbidities observed in individuals with severe obesity, it is not surprising that depressive symptoms emerge as a key factor influencing psychosocial functioning in this population.

A statistically significant relationship was identified between the psychosocial functioning component of quality of life and depressive symptoms, suggesting that individuals experiencing greater psychological distress tend to report poorer psychosocial well-being. Additionally, regression analyses confirmed that depressive symptom is a significant predictor of psychosocial functioning, indicating that higher levels of depressive symptoms are associated with greater impairments in overall quality of life. These findings are consistent with previous studies emphasizing the crucial role of depressive symptoms in preoperative adjustment [18, 32]. Based on the standardized coefficients, depressive symptoms ($\beta$ = 0.24) emerged as the strongest predictor of psychosocial functioning, having a slightly larger effect than disordered eating symptom severity ($\beta$ = 0.20), even when accounting for the different measurement scales [31]. Previous research highlights that depression before surgery is associated with lower postoperative quality of life [33] and increases the risk of less weight loss, weight regain, and the need for reoperation [34, 35]. In line with these findings, our results show that individuals with higher levels of depressive symptoms are more vulnerable to psychological distress, which has been linked to poorer postoperative outcomes. Additionally, depressive symptoms may contribute to prolonged hospital stays after surgery [35]. These findings emphasize the importance of early identification and treatment of depression during the perioperative period.

The strong association between depressive symptoms and psychosocial functioning may reflect a bidirectional relationship. On one hand, symptoms such as anhedonia, fatigue, and social withdrawal can diminish patients’ capacity to participate in meaningful interpersonal and occupational roles, thereby lowering their quality of life [15, 33]. On the other hand, ongoing functional impairments—particularly those arising from obesity-related stigma or physical limitations—may foster feelings of hopelessness, reduced self-efficacy, and affective dysregulation, which in turn exacerbate depressive symptomatology [13, 14]. These dynamics underscore the need to consider depressive symptoms not merely as a risk factor, but also as an outcome of impaired psychosocial functioning.

In our study, 52 participants (29.7%) were identified as having disordered eating sypmtoms based on EDE-Q results. While this rate is consistent with some previous findings, other studies have reported higher prevalence rates of disordered eating symptoms among bariatric surgery candidates [36, 37]. One possible explanation for the relatively lower rate observed in our study is the tendency of participants to present themselves in a more favorable light during the preoperative evaluation process. Given that approval from the health board is required for surgery, some individuals may underreport symptoms related to disordered eating behaviors in an effort to secure medical clearance. Conversely, studies reporting lower rates of eating disorders than ours have often focused exclusively on binge eating disorder, rather than assessing a broader spectrum of eating disorder pathology [38]. The variability in reported prevalence rates across different studies likely stems from methodological differences, including variations in diagnostic criteria, assessment tools, and sample characteristics. The absence of standardized and universally accepted screening protocols for disordered eating symptoms in bariatric surgery candidates further complicates direct comparisons across studies. Given the well-documented comorbidity between obesity and disordered eating symptoms, careful and comprehensive screening for disordered eating behaviors should be prioritized in preoperative evaluations to ensure that psychological factors influencing treatment outcomes are adequately addressed.

Our findings indicate that the presence of disordered eating symptoms is significant predictor of psychosocial functioning, particularly in relation to quality of life. Consistently, studies examining quality of life in individuals with obesity have reported a statistically significant negative impact of eating disorders on overall well-being [36]. In our study, the strong negative relationship observed between disordered eating symptoms and psychosocial functioning may be attributed to the specific nature of the psychosocial domain of quality of life assessments, which primarily captures the psychological and emotional consequences of obesity. This reinforces the importance of addressing disordered eating behaviors as part of a multidisciplinary approach to optimize psychosocial well-being and surgical outcomes in bariatric patients.

Disordered eating behaviors, particularly those characterized by emotional eating or binge episodes, may operate as maladaptive strategies for coping with negative emotions in bariatric populations [6]. These behaviors are frequently accompanied by feelings of shame and self-criticism, which can promote avoidance of social situations and impair psychosocial engagement [39]. Furthermore, internalized weight stigma may heighten vulnerability to both disordered eating and social isolation, creating a self-perpetuating cycle that undermines psychological well-being [13]. Addressing this cycle in preoperative interventions may be critical to improving long-term surgical and psychosocial outcomes.

Participants’ mean RSES scores aligned with some studies [15, 40] but were higher than those reported elsewhere [41, 42]. These variations may stem from differences in education, employment, expectations, stigma exposure, and medical or social factors.

Direct comparisons of body satisfaction are challenging due to variations in assessment tools. However, extensive research links obesity to body dissatisfaction [43]. While prior studies found significant negative correlations between self-esteem, body satisfaction, and quality of life [44, 45], our study did not identify them as predictors. This may be due to their complex interplay with depressive symptoms, where dissatisfaction lowers self-esteem, contributing to depressive symptoms, which emerged as the primary predictor in our regression model.

Although self-esteem was not a predictor in our study, literature suggests that enhancing self-esteem may improve surgical outcomes [16]. Research on obese women supports self-esteem and body satisfaction as predictors of psychosocial functioning [29]. While not identified as key factors in our analysis, their significant associations with psychosocial functioning underscore their relevance in treatment. A previously published study by Polat et al. [29] (2019), for example, also examined psychosocial functioning in individuals with obesity; however, it focused solely on voluntarily enrolled women in a non-surgical outpatient lifestyle program. In contrast, the present study includes both men and women undergoing mandatory psychiatric evaluation as part of a bariatric surgery protocol and integrates additional variables such as disordered eating symptoms. These differences in sample characteristics, clinical context, and analytical scope highlight the unique contribution of the current study. Addressing body image concerns, particularly through psychotherapy, may provide therapeutic benefits [39].

In our sample, psychosocial functioning was not significantly associated with gender, education level, income, or BMI. Although some studies have linked female gender and higher education to increased psychosocial distress in obesity [15, 45, 46, 47], these associations were not observed in our data, possibly due to the overriding influence of psychological factors such as depressive symptoms and disordered eating.

In our study, no significant differences in psychosocial functioning were observed between obese and morbidly obese participants, suggesting that BMI alone may not be a primary determinant of preoperative psychosocial well-being. While some studies have reported greater declines in mental health-related quality of life in individuals with class II obesity compared to those with class III obesity [48], others have linked higher preoperative BMI and comorbid depression/anxiety to increased postoperative BMI [49]. These discrepancies highlight the complex and multifaceted nature of psychosocial functioning in individuals with obesity, which extends beyond BMI classification alone. The lack of a significant BMI-related effect in our study suggests that psychosocial functioning is likely shaped by a broader range of psychological and social factors. This underscores the importance of adopting a more holistic approach in preoperative assessments, considering not only BMI but also the psychosocial and emotional context in which obesity-related distress occurs.

The rising prevalence of obesity as a global health concern and the difficulty in maintaining well-being after bariatric surgery highlight the critical need to address underlying psychosocial factors. Psychological predispositions that negatively affect quality of life are associated with suboptimal outcomes following bariatric surgery. Identifying these individuals during the preoperative phase or early postoperative period and providing targeted psychological interventions can significantly enhance both quality of life and surgical success [50]. Furthermore, evidence from other studies indicates that managing psychological distress before and after surgery leads to more favorable outcomes [51, 52]. In our study, Depressive symptom severity and disordered eating risk were identified as negative predictors of psychosocial functioning. Therefore, recognizing the potential impact of depressive symptoms and disordered eating symptoms on bariatric surgery outcomes and implementing psychiatric evaluation and interventions to improve psychosocial functioning are key to optimizing results.

The sample was selected from patients attending medical faculty hospitals, and this population may differ from those seeking care at state or private hospitals. Additionally, participants may have tended to present themselves more favorably to obtain approval for bariatric surgery. The cross-sectional design of our study is another limitation, as it does not allow for generalizations or the establishment of causal relationships. Moreover, the artificially created physical and psychological effects of the study environment may have led participants to exhibit atypical reactions, a phenomenon known as the Hawthorne Effect [53]. Reporting bias may also have influenced our results, given that the participants were a group actively seeking treatment. Although the OP-S is a validated and widely used measure of psychosocial functioning in obesity, it primarily assesses weight-related social impairment and may not capture broader emotional or cognitive dimensions of psychological distress. Its self-report format may also introduce social desirability bias, particularly in preoperative settings where patients may underreport difficulties in an effort to secure surgical approval. These limitations should be considered when interpreting the findings. Furthermore, although depressive symptoms and disordered eating symptoms were modeled as predictors of psychosocial functioning, some conceptual overlap with the OP-S scale cannot be fully ruled out. While the OP-S primarily targets social and behavioral impairments associated with obesity, certain items may be indirectly influenced by affective symptoms. This potential overlap should be acknowledged as a limitation of the current model and considered when interpreting the findings.