While in South Africa a few months ago, an irritating yet clever radio announcer, during a joke-based interlude between songs, made the following comment:
"Research has shown that insomnia leads to depression. Other research has shown that depression leads to insomnia. Still other research has shown that research leads to more research."
Seems like a great indictment of some of less-than-careful, data mining-y studies that often find their way into decent journals and on the evening new. (Note: I'm not anti-epidemiology.)