• Change in the Number of Moderate to Severe Headache Days Within a 28 Day Average Period in Six Months Compared to Baseline [ Time Frame: Baseline (pre-randomization), months 5 and 6 post randomization ] [ Designated as safety issue: No ]
  (Number of moderate to severe headache days (as defined by the International Headache Society Guidelines (2006)) counted over a 28 day diary period at baseline (before treatment with propranolol or placebo)) minus (the number of moderate to severe headache days counted over a 56 day diary period (weeks 16-24 post treatment) divided by 2).
  
  

• Number of Subjects Experiencing at Least a 30% Reduction in 28-day Moderate to Severe Headache Days [ Time Frame: 6 months post randomization ] [ Designated as safety issue: No ]
  
• Number of Subjects Experiencing at Least a 50% Reduction in 28-day Moderate to Severe Headache Days [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  
• Change From Baseline in Beck's Depression Inventory FastScreen Score at 6 Months [ Time Frame: Baseline and 6 months ] [ Designated as safety issue: Yes ]
  Total score from Beck's Depression Inventory FastScreen at 6 months minus total score from Beck's Depression Inventory FastScreen at baseline. Scale scores range from 0 to 21 with higher values indicating worsening depression. the following categories separate participants into groups of depression levels: Minimal (Score 0-3), Mild (Score 4-8),Moderate (Score 9-12),Severe (Score 13-21).
  
  
• Change From Baseline in Migraine Disability Assessment (MIDAS) Score at 6 Months [ Time Frame: Baseline and 6 months ] [ Designated as safety issue: No ]
  MIDAS scoring ranges from 0 to 270. The scores are divided into ranges of disability with higher scores indicating increased disability as follows: 0-5 (Grade I - Minimal or infrequent disability); 6-10 (Grade II - Mild or infrequent disability); 11-20 (Grade III - Moderate disability); and 21+ (Grade IV - Severe disability).
  
  
• Change From Baseline in Migraine Specific Quality of Life (MSQ)-Role Restrictive Score at 6 Months [ Time Frame: baseline and 6 months post randomization ] [ Designated as safety issue: No ]
  The MSQ (version 2.1 copyrighted 1992, 1996, 1998 by Glaxo Wellcome Inc., Research Triangle Park, North Carolina) is a 14 item questionnaire. Item responses are summed and scored as a total score and three domains: Role Preventive, Role Restrictive, Emotional Function. Scores within each domain are rescaled to range from 0 to 100. A lower score indicates a poorer quality of life associated with that domain or in total. Because of the observed interaction within a domain, only domain scores were used as outcome measures for this study.
  
  
• Change From Baseline in Migraine-Specific Quality of Life (MSQ)-Role Preventive at 6 Months [ Time Frame: Baseline and 6 months ] [ Designated as safety issue: No ]
  The MSQ (version 2.1 copyrighted 1992, 1996, 1998 by Glaxo Wellcome Inc., Research Triangle Park, North Carolina) is a 14 item questionnaire. Item responses are summed and scored as a total score and three domains: Role Preventive, Role Restrictive, Emotional Function. Scores within each domain are rescaled to range from 0 to 100. A lower score indicates a poorer quality of life associated with that domain or in total. Because of the observed interaction within a domain, only domain scores were used as outcome measures for this study.
  
  
• Change From Baseline in Migraine-Specific Quality of Life (MSQ) - Emotional Function at 6 Months [ Time Frame: Baseline and 6 Months ] [ Designated as safety issue: No ]
  The MSQ (version 2.1 copyrighted 1992, 1996, 1998 by Glaxo Wellcome Inc., Research Triangle Park, North Carolina) is a 14 item questionnaire. Item responses are summed and scored as a total score and three domains: Role Preventive, Role Restrictive, Emotional Function. Scores within each domain are rescaled to range from 0 to 100. A lower score indicates a poorer quality of life associated with that domain or in total. Because of the observed interaction within a domain, only domain scores were used as outcome measures for this study.
  
  

Chronic migraine affects about 2 percent of all adults. Currently there are no effective preventative treatments to deal with this disabling condition. Three randomized, placebo-controlled trials found that topiramate was an effective, safe and generally well-tolerated drug for treating chronic migraine. As a result of these trials, topiramate is becoming the standard treatment among headache specialists. Experts agree that treatment with combinations of preventive agents is required in the majority of individuals with chronic migraine for maximal headache relief. No randomized trials have assessed the value of frequently used combinations of preventive agents for chronic migraine.

The goal of this trial is to determine if adding a second drug to topiramate treatment will further reduce the headache burden for people with this condition. In the study, 250 participants with chronic migraine will be randomized to two groups - treatment with topiramate and propranolol or topiramate and placebo. Participants will be followed for six months.