Before everyone shouts that the correlation may be spurious, I would like to say that some drugs (e.g. Parkinson's disease drugs), can have significant psychological side-effects, like increasing impulsivity and reducing risk aversion for those who experience them. People leave their spouses, buy expensive cars, get tattoos, and yes, leave their jobs to pursue entrepreneurship.<p>My point is that it's not far fetch to link infection to impulse, cause infection may change the chemical functioning of the brain.