Individuals with body dysmorphic disorder (BDD) are excessively preoccupied with an imagined or slight defect in appearance. Higher aesthetic sensitivity in facial proportions may explain why BDD patients are severely disturbed by a small defect in their appearance.Aesthetic sensitivity can be defined as an awareness and appreciation of beauty and harmony, with three components: i) perceptual (ability to differentiate variations in aesthetic proportions); ii) emotional (degree of emotion experienced when viewing beauty or ugliness); iii) evaluative (aesthetic standards, values and identity).Fifty BDD patients were compared with two non-clinical control groups; 50 art & design controls and 50 non-art controls. A facial photograph of the participant was manipulated using computer graphic techniques, to create a 9-image symmetry continuum. Presented with the continuum on a computer, participants selected and rated images representing their self-actual, self-ideal, idea of a perfect, most physically attractive, most pleasure and most disgust. Control symmetry continua examined the specificity of the disturbance.As predicted, BDD patients displayed increased accuracy in their self-actual estimation and greater sensitivity to aesthetic proportions. BDD patients were not distorted in their perceptual processing but appeared exclusively disturbed in their negative emotional/evaluative processing of their own face. However, BDD patients did not express a higher aesthetic standard of beauty compared to controls. A significant discrepancy between BDD patients' self-actual and self-ideal, resulting from an absent self-serving bias in their self-actual estimation, a bias notably exhibited by controls, may be the crucial determining factor and potential source of their disturbance. BDD patients also overvalued the importance of appearance and self-objectified. These aesthetic evaluations may interact with aesthetic perceptions and emotions to predispose them to and/or maintain the disorder.Investigating the role of personality/psychological factors, path analyses suggested that body shame mediates the relationship between aesthetic sensitivity and BDD symptomatology. Clinical implications are discussed.3