UNA BEGAN GETTING headaches when she was thirteen. "At first," she explains, "they were few and far between but [over time] . . . they became worse and more frequent. I went to my doctor and was diagnosed with migraine [a type of headache]."During the next few years, Una's headaches worsened. By the time she reached her final year of high school, she had been hospitalized twice due to debilitating headaches and missed over six weeks of school in one year. In fact, because of her headaches, Una doubted whether she would be able to pass her final exams and graduate.

Like Una, over 45 million Americans suffer from habitual, recurring headaches. This is more than the number of Americans with either heart disease, asthma, or diabetes. Indeed, at any one time, an estimated 20 million Americans are experiencing a headache.

Although headaches are...