Objective For the treatment of obesity, both conservative and surgical procedures are available. Psychological factors are likely to influence the choice of treatment; however, to date, systematic studies that investigate these factors are few in number. The aim of our study was to analyze whether patients who undergo a surgical treatment differ from those who require a conservative treatment in regard to psychological factors, regardless of their somatic conditions. Furthermore, predictors of treatment choice will be examined. Methods A total of 244 patients (189 women), with a mean body mass index of 45.1 kg/m2, underwent a weight reduction treatment, with 126 patients undergoing bariatric surgery and 118 patients participating in a conservative, multimodal outpatient weight reduction program. Differences in the results of the psychological questionnaires between conservatively and surgically treated patients were evaluated through the use of t-tests, χ2-tests and an ANCOVA. For the analysis of the predictors, logistic regression models were calculated. Results Surgically and conservatively treated obese patients differ in psychological, somatic, and socio-demographic factors. The psychological differences between the groups are independent of obesity- related co-morbidities, such as body mass index (BMI), type 2 diabetes mellitus, hypertension and coronary heart disease. The following psychological and somatic factors equally predict the choice of bariatric surgery: apathy, delegated active coping, a sense of coherence, complaints, type 2 diabetes mellitus, BMI, and age. Conclusion Longitudinal studies are required to assess the predictive value of the psychological factors in regard to the postsurgical weight course to improve the pre-surgical screening and treatment selection process. The pre-surgical identification of psychological predictors should result in a more personalized medicine course and may ensure long term outcomes.
