Evaluation of the Effectiveness of Topiramate in Preventing the Transformation From Episodic Migraine to Chronic Daily Headache.

Inclusion Criteria: * To qualify for this study you must be 18-65 years old * have a history of migraine headaches for at least 1 year * experience at least 10 but less than 15 migraine headache days and less than 15 total headache days/month * able to take oral medication * able to understand and sign the informed consent and to complete headache diaries. Exclusion Criteria: * You will not be able to participate in the study if you previously discontinued Topiramate because it did not make you feel better or it made you feel different * have migraine aura without headache * have a positive urine drug screen * have a history of kidney stones * have a history of suicide attempt * pregnant females * already on a migraine preventive medicine.