Objective: The study begins by analysing the psychometric properties of the Nepean Dyspepsia Index-Short Form (NDI-SF), before moving on to study quality of life in patients with functional dyspepsia (FD) and the psychopathological features that underlie the disorder in three groups of subjects: patients with eating disorders (ED), psychiatric patients (non-ED), and a group of students, all of whom fulfilled Rome III criteria for FD. The analysis specifically focused on the relationship between thought-shape fusion (TSF) and functional dyspepsia, and hence on the potential repercussions this could have on the quality of life of patients with eating disorders. Methods: The sample comprised 78 ED outpatients, 77 non-ED outpatients, and 90 university students, all of them with associated FD (Rome III criteria). The mental disorders (ED and non-ED) fulfilled the diagnostic criteria of DSM IV-RT. In all cases, the symptoms of dyspepsia, the related quality of life, anxiety, depression, and TSF were determined. Results: Satiation and bloating were significantly higher in ED patients. Correlations between dyspepsia and TSF were initially positive and significant in all cases, but significance was only maintained in the group of ED patients after controlling for the other psychopathological variables. Regarding the ED group, the regression analysis revealed the following predictors of quality of life: dyspepsia, depressive symptomatology, TSF-conceptual, TSF-interpretative and total TSF. Discussion: The cognitive distortion of TSF appears to constitute a general bias common to all eating disorders, with specific effect on the characteristic symptoms of FD.