For some individuals prone to migraine, this susceptibility may not necessarily interfere with their sex life and may in fact improve their libido, according to research published in the journal Headache.

"The goal of this research was to understand migraine better," lead author Dr. Timothy T. Houle told Reuters Health. "By better understanding how the brain is altered with this syndrome, we can develop better drugs in the future."

"Migraines have other commonly associated symptoms, such as sleep abnormalities and a higher risk of depression. Altered sex drive may be another quirk of being a migraine," he added.

Although it is commonly believed that sex drive is reduced by headaches, and sexual intercourse can cause specific types of headaches, Houle and his associates note, other research has suggested that sexual intercourse may alleviate the pain of migraine in some patients.

Houle, from Wake Forest University School of Medicine in Winston-Salem, North Carolina, and his associates tested the theory that migraine and sexual desire may both be associated with serotonin. Evidence for this is the reduced libido that often accompanies depression treatment with a selective serotonin reuptake inhibitor, which increases brain levels of serotonin, whereas migraine is associated with reduced serotonin levels.

To investigate this complex relationship, Houle, and his associates recruited 59 adults who had at least 10 headaches annually. Twenty-three subjects (7 men and 16 women) were classified as having migraine, and 36 (18 men and 18 women) as having tension-type headache.

The subjects completed the self-administered Sexual Desire Inventory (SDI), which includes nine items measuring dyadic desire and five measuring solitary sexual desire. "It allowed the subjects to rate how much they think about sex and how much they desire sex," Houle told Reuters Health.

"Men reported about 24-percent higher sex drive than did women," the researcher said, "and the difference between migraine and tension-type headache was almost equivalent -- 20 percent." Thus, women with migraines reported about the same relative levels of sex drive as men with tension type headaches.

On the nine-point scale the subjects specifically rated their own sexual desire compared with that of others of the same age and sex. The migraine patients reported the highest level (5.0), which is "above the expected median (4.0) on this item," Houle and his colleagues note. Those with tension-type headaches gave themselves an average rating of 3.7 for this item.

What was even more interesting, Houle said, was that the migraine patients were aware that they rated their sexual desire higher than that of other patients in the group.

However, he added that "there was no evidence that their sexual desire was beyond that of high normal or that they are hypersexual."

"It can now be hypothesized that a serotonergic link may be implicated in both migraine headaches and sexual desire," the researchers conclude. Also, serotonin receptors also appear to be involved in several aspects of sexual functioning.

On the other hand, they point out that there are multiple classes and subtypes of serotonin receptors. Therefore, they conclude that "any neurochemical mechanism(s) that might link serotonin and migraine would likely be sophisticated and multifactorial."

Houle concluded: "Our research is now focused on mathematical modeling to predict migraine activity, to see if we can figure out for any individual patient when they are at increased risk of an attack so it can be aborted."