Topiramate Augmentation in Bulimia Nervosa Partial Responders

Inclusion Criteria: * Male or female subjects meeting Diagnostic and Statistical Manual IV edition (DSM-IV) diagnostic criteria for bulimia nervosa (BN). * Subjects must be between the ages of 18 and 60 years. * Subjects must currently demonstrate partial response to a standard BN pharmacotherapy treatment. * Women of child-bearing potential must be practicing an accepted method of birth control (barrier method or oral contraceptive) and have a negative pregnancy test at baseline. * Subjects must be of good general health by history, laboratory assessment and physical exam. * Subject's BMI must be \>20 and \<27 kg/m\^2. Exclusion Criteria: * Subjects who are allergic to topiramate. * Subjects who meet DSM-IV criteria for anorexia nervosa. * Women who are pregnant or nursing at the time of study. * Subjects experiencing clinically significant, unstable neurological, cardiac, hepatic or renal disease or narrow angle glaucoma. * Subjects with a history of nephrolithiasis. * Subjects with a serum potassium \<3.0 mmol/L * Subjects cannot start psychotherapy during the study. * Subjects currently or with a past history of meeting DSM-IV diagnostic criteria for schizophrenia, schizoaffective disorder, or bipolar disorder. * Subjects receiving antipsychotic agents, mood stabilizers, antianxiety agents or other non-antidepressant psychotropic agent currently. * Subjects currently or with a history within the past year of meeting DSM-IV diagnostic criteria for substance abuse. * Subjects who are experiencing clinically significant suicidal ideation (subjects will be referred to appropriate caregiver). * Subjects who have participated in an investigational drug study in the past 30 days. * Subjects who are receiving any prescription medications other than oral contraceptives that will interact with any of the study medication.