Inclusion Criteria:

Subjects (aged 12 to 23) were included if they

• Met the criteria of bulimia nervosa or eating disorder NOS with binge-eating behavior in DSM-IV-TR,
• Had weight > or = 100th % of expected body weight for their age,
• Engaged in binge eating at least once a week for 9 out of the 12 weeks prior to the study entry, and
• Were judged by a clinician to be stable enough to be treated for their psychiatric condition as an outpatient (i.e, no acute suicidality, hallucination, unstable vital signs or persistently abnormal laboratory results due to eating disorder).

Exclusion Criteria:

• Subjects whose psychotropic medications had been changed within 4 weeks prior to the entry or who had started psychotherapy within 3 months prior to the entry were excluded.
• Subjects were also excluded if they were taking carbonic anhydrase inhibitors, carbamazepine, phenytoin, phenobarbital, valproic acid, evening primrose oil or oral contraceptives.
• Other exclusion criteria were: history of substance use disorders within the 6 months prior to study, IQ < or = 70, medical conditions causing weight loss (i.e., hyperthyroidism, diabetes mellitus type 1, malignancy) or that contra indicate treatment with topiramate (nephrolithiasis or glaucoma), history of non response or poor tolerance to topiramate in the past and history of non-adherence to medication treatment.