Irregularities in hormones produced by the hypothalamus, the area of the brain that regulates such basic functions as hunger and body temperature, may underlie chronic migraines. The findings provide hope for the 2% to 3% of the general population who suffer from the debilitating headaches, since drugs that regulate these hormones could prevent or reduce the severity of the headaches, according to Dr. Mario Peres, the study's lead author.
According to the report, chronic migraine sufferers had higher levels of cortisol, a stress hormone that is involved in the control of blood pressure and blood sugar metabolism, and were more likely to have delayed peak levels of melatonin, the hormone that controls sleep cycles. Nearly half of patients with migraines had a delay in peak melatonin levels, compared with none of the healthy volunteers, and those with migraines and insomnia had lower peak melatonin concentrations.
Normally, melatonin levels are highest 6 to 8 hours after sunset but levels were found to peak after 3 AM in people with chronic migraines. Levels of prolactin, a hormone that rises during pregnancy to stimulate milk production, were lower among those with migraines, the report indicates. Peak levels of prolactin were low in 53% of patients compared with 22% of those without headaches. This hormone is partially regulated by a brain chemical called dopamine.
Chronic migraines may occur with other conditions such as depression, anxiety disorder and insomnia. While the headaches take a toll on patients' quality of life and place an economic burden on society, little is known about their cause. Overall, these results support the involvement of the hypothalamus in the pathophysiology of chronic migraine.