This study was conducted at the Bariatric Centre of Excellence IFSO-EC of “La Sapienza” University of Rome, in collaboration with the Department of Dynamic, Clinical Psychology and Health Studies of “La Sapienza” University of Rome.
The participants were recruited among patients attending the psychological assessment for bariatric surgery eligibility in the Bariatric Centre of Excellence IFSO-EC of “La Sapienza” University of Roma, between November 2020 and July 2021. Informed consent was obtained from all individual participants included in the study. The recruitment has been carried out by a trained clinical psychologist one month before surgery and the patients completed the self-reported anonymous questionnaires alone in a private room.
The exclusion criteria were (a) not being Italian citizen; (b) presence of psychopathology; (c) presence of drugs or alcohol abuse; (d) Ineligibility for surgery according to the European Guidelines on Metabolic and Bariatric Surgery ; (e) undergoing primary bariatric procedures. The exclusion criteria were evaluated during the preoperative psychological assessment.
This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of University Department of Dynamic, Clinical Psychology and Health Studies of “La Sapienza” University of Rome (11/27/20, No 0001118).
Patients underwent an interview conducted by the clinical research psychologist where they were asked socio-demographic information such as gender, age, weight, hight and BMI, marital status, education level and work status. The questionnaires administered were the following.
The Symptom Checklist-90-Revised (SCL-90-R)  is a widely used checklist that measures levels of psychological symptoms experienced in the past week, on a five-point Likert scale ranging from "not at all" to "extremely." The global measures are the Global Severity Index (Global Severity Index), the Positive Symptom Total (PST) and the Positive Symptom Distress Index (PSDI). In addition, there are nine subscales describing different psychological aspects. The Italian version was used  and the reliability coefficients of internal consistency were good for this study (Cronbach's alpha values = .76-.87).
The Body Uneasiness Test (BUT)  is a self-administered questionnaire for the clinical assessment of body image disorders and related psychopathologies. It consists in two parts: BUT-A is a 34-item scale which indicates the presence of body uneasiness, and its’ global measure is the Global Severity Index (BUT-A GSI) and, in addition, there are five subscale scores regarding specifics uneasiness on body image; the BUT-B is a 37-item scale assessing specific worries about body parts, shapes, or functions. The global measures are the Positive Symptom Total (BUT-PST), and the Positive Symptom Distress Index (PSDI). Also, the eight subscales subdivide different parts of the body. The validity of BUT demonstrated good internal consistency (BUT-A Cronbach’s α values=.57-.88; BUT-B Cronbach’s α values=.64-.88)
The 12-item Short Form Survey (SF-12)  is a generic quality of life (QoL) instrument that includes a subset of 12 items from the 36-item Short Form Survey. The global measure is Total Score (SF-12 Total), with the subscales of Physical Health and Mental Health. Higher scores indicate an improvement in QoL. For this study, the Italian version was used  and the internal consistency reliability coefficients were good (Cronbach’s α value =-.63).
The Beck Inventory Scale II (BDI II)  assesses the presence and severity of depressive symptoms. A total score above 10 is the beginning of the presence of depression. High scores show greater severity of depression. For this study, the Italian version was used  and it showed good internal consistency with a Cronbach coefficient α of .84.
The Beck Hopelessness Scale (BHS)  assesses the presence of hopelessness and negative expectations about the future, indicating the risk of suicide. It consists of 20 items in the form of yes-no questions and higher scores indicate more severe despair. For this study, the Italian version was used  and internal consistency was good with a Cronbach's α of .73.
Continuous variables (age, weight, SCL-90-R, BUT, SF-12, BDI II and BHS) are presented as mean ± standard deviation, counts or percentages. Categoric variables (sex, BMI, education level, work, and marital status) are presented as counts and percentages.
Correlational analyses (Pearson's r) between weight, BMI, BUT and the psychological outcomes were performed. Moreover, multiple regression analyses were performed including BMI, BUT-A Global Severity Index and BUT-B Positive Symptom Distress Index as predictors of psychological outcomes.
All analyses were performed with STATISTICA 8.0 software (StatSoft Inc.) and criterion for statistical significance was p < 0.05.