Good Worry v Bad Worry

▲ Dont Fear, Worry ▼

From article about the depression/anxiety study:

Despite their depression, the worriers also did better on the emotional word task than those depressives who were fearful or vigilant. The worriers were better able to ignore the meaning of negative words and focus on the task, which was to identify the color – not the emotional content – of the words.

These results suggest that fearful vigilance sometimes heightens the brain activity associated with depression, whereas worry may actually counter it, thus reducing some of the negative effects of depression and fear, Miller said.

Chronic worrying might be another form of rumination. For more discussion, see:

Rumination, What Upside?
Depression's Upside - NYTimes
It's What You Learn, Not What You Think