I googled 'suicide gene' but cancelled the search at the last second. I didn't want to know. Plus, I already knew. People ask: but how does this happen? To think that even with all the security measures we employ these days to keep things out - fences and motion detectors and cameras and sunscreen and vitamins and deadbolts and chains and bike helmets and spinning classes and guards and gates - we can have secret killers lurking inside us? That we can turn on our happy selves the way tumours invade healthy, wholesome organs, the way 'normal' moms suddenly throw their infants off the balcony is...who wants to think about that shit?