Dealing with uncertainty is an unavoidable part of daily life. Because we can’t see the future, we can never be certain about what exactly is going to happen day to day. Research has found that people vary in their ability to tolerate uncertainty. That is, some people are fine with having a lot of uncertainty in their lives, and other people cannot stand even a small amount of uncertainty. When people who are intolerant of uncertainty are exposed to a little bit of uncertainty, they also have a strong reaction: they worry, and do everything they can think of to get away from, avoid or eliminate the uncertainty. But being very intolerant of uncertainty can cause problems, since it leads to a lot of time-consuming and tiring behaviors, causes stress and anxiety, and is the major fuel for worry.
Buhr, K., and Dugas, M.J. (2002). The intolerance of uncertainty scale: psychometric properties of the English version, Behaviour Research and Therapy, 40, 931-945.