Association between severity of erectile dysfunction and SIEDY Scale 1, Scale 2 and Scale 3 (organic, relational and intrapsychic pathogenetic components of erectile dysfunction, respectively). Data are derived from a population of 1,873 men aged 18–44 years, representing the first tertile of age in a population of patients consulting the Sexual Medicine and Andrology Unit of the University of Florence for erectile dysfunction. Data are adjusted for age, smoking habits, alcohol intake and education. Erectile dysfunction is defined according to a previously validated definition (21) using the sum of the scores obtained from question 1A (Do you have full erection sufficient for penetration? Rating 0= always, 1= often, 2= quite often and 3= sometimes) and question 2 (Does it occur to have a normal erection which you are not able to maintain? Rating 0= sometimes, 1= quite often, 2= often, and 3= always) of SIEDY, which reproduce the definition of erectile dysfunction as “The persistent inability to achieve and/or maintain an erection adequate for satisfactory sexual activity” (1). SIEDY, Structured Interview on Erectile Dysfunction.