Caffeine also appears to work by itself. And doctors often treat migraines by prescribing combinations of caffeine and other drugs that constrict blood vessels in the brain. Premenstrual Syndrome and Breast Lumps. Some women swear that it does, but the research isn't clear. But for more complicated tasks, like complex word problems, caffeine has also been shown to worsen performance.
Caffeine can delay the onset of sleep.
In a recent study, women in Iowa who routinely took caffeine-containing medications reported having more trouble falling asleep at night than women who took no caffeinated medications.