“The most important and well-studied depression-prone personality trait is neuroticism. People who score high on neuroticism are prone to anxiety and other negative feelings (think Woody Allen) and have stronger upsets in response to stresses, be it sudden job loss or terrorist attack. There is robust evidence that neurotic temperaments predispose people to experience periods of low mood and periods of more severe, long-lasting depression. A wealth of data indicates that highly neurotic people are like the fabled ant: they worry about bad things that may or may not happen in the future, and they are more vigilant about threats, even those that are distant, hidden, or subtle.”