Treatment for binge-eating disorder (BED) is directed towards either the physical or psychopathological impairments, and often does not cover all the alterations characterizing the disease. In 30 BED patients, we monitored the effects of three types of 6-month treatment, randomly assigned to one of the three treatment groups, each consisting of 10 patients. Group 1 received a 1700-kcal diet (21% proteins, 27% lipids, 52% carbohydrate), cognitive-behavioural therapy (CBT), sertraline (50–150 mg/day) and topiramate (25–150 mg/day); group 2 received the same diet, CBT, sertraline; and group 3 received nutritional counselling and CBT. Binge frequency and weight were assessed every month. The Eating Disorder Inventory-2, the Symptoms Check List-90-Revised (SCL-90-R) and the Personality Diagnostic Questionnaire-4-Revised (PDQ-4-R) were administered before and after treatment. Binge frequency and excessive weight decreased significantly only in group 1 patients, in whom improvement was noted in total Eating Disorder Inventory-2 scores and the subitems ‘bulimia’, ‘drive for thinness’, ‘maturity fear’, ‘ascetism’, in total SCL-90-R scores and in the subitem ‘somatization’, in PDQ-4-R subitems ‘schizotypic personality’ and ‘dependent personality’. Group 2 patients improved on the SCL-90-R subitems ‘depression’ and ‘interpersonal relationship’ and in the PDQ-4-R ‘schizoid personality’. Combination therapy seems to be the only fully effective treatment in BED patients.