Answer: die
Step-by-step explanation:
Okay, let us first fill in the gap in the question.
PS: the capitalized word is the missing word.
"In one study, nearly 4000 English adults (ages 52 to 79) provided mood reports from a single day. Compared with those in a good mood, those in a blue mood were twice as likely to DIE within the next five years."
This study, that is the one that was said to have been conducted above was conducted by researchers in the year 2011. The research aim was to show that when someone is happy, the person can live longer lives than when the person is not happy. The study was also to show the 'evil' or disadvantage of being stressed as related to long life.