The present invention provides methods of diagnosing migraine attacks and determining predisposition of an individual to the development of migraine based on sodium level in the cerebrospinal fluid (CSF) and/or brain extracellular fluid. The invention also provides methods of treating migraine, wherein the individual is selected for treatment based in the individuals sodium level in the CSF and/or brain extracellular fluid. The CSF sodium level may be based on the sodium concentration in the saliva.
