My first migraine arrived in a fuzzy cloud of reds and purples, a stab of pain that left me bent over in the back of an auto-rickshaw, squinting and nauseous, on my morning commute to Connaught Place, in New Delhi. Months later, when I left India, I thought that the headaches would disappear along with the chaos of the overcrowded capital. They didn't. And finally, after months spent stumbling into my room, drawing the curtains, and lying in the darkness for hours wishing for sleep, I went to an internist, who prescribed a brain scan. When he found nothing, he told me what I already suspected: migraines. I asked him the cause, but all he could say was, "Stress, probably, which can mean any number of things."