Worrying sucks. Not only is it unpleasant, but also often quite useless, as your brain finds itself hijacked by ruminations about some future event that you may not be able to do anything about anyway. (Here it is, a beautiful day in early spring, and instead of paying attention to the blossoms on the cherry tree I'm stewing in thoughts about neuroscience...)
As I've written about earlier, however, worry isn't all bad. Last year a team of researchers in England recently found that depressed people who suffer from anxiety as well actually have a longer life expectancy from those who are depressed but not anxious. Mused team leader Dr Robert Stewart, "a little anxiety may be good for you" because it leads sufferers to reach out and seek help when they need it.
Now a new study provides more ammo to the worry-is-good camp and suggests another mechanism for its benefits. Fretting, it seems, can help counteract that activation patterns that depression tends to elicit.
A team at the University of Illinois used an fMRI machine to scan the brains of patients who were depressed but not anxious, anxious but not depressed, or both depressed and anxious (Yippee!). The researchers asked the subjects to perform a task called the Stroop test, which involves identifying the color of an emotionally laden word ("birthday," say, or "murder"). Because people are used to looking for the meaning of a word, rather than its color, this task requires top-down executive control, a function associated with the left dorsolateral prefrontal cortex (DLPFC).
Based on the results of a previous fMRI experiment, the researchers already knew that anxiety comes in not one flavor, but rather two, each of which exhibit very different patterns of activity. People suffering from "anxious arousal" are prone to fearful vigilance and panic attacks, and exhibit an unusual degree of activity in the right inferior temporal lobe. Those suffering from "anxious apprehension" engage in chronic worry and tend to exhibit activity in the left frontal lobe.
Sorting through all the permutations and combinations, they found that the subjects who were both depressed and panicky showed even higher activity in the right frontal cortex, and did not perform well on the Stroop test as non-anxious subjects. Their pattern of activation apparently compounded the cognitive problems associated withdepression. The authors write that "when anxious arousal co-occurs with depression, it may cause difficulty, or increase difficulty, in one type of cognitive processing (top-down attentional control, or selective attention, associated with left-prefrontal processing)." In other words, being panicky makes it even harder for a depressed person to focus.
On the other hand, the worriers performed better on the Stroop test, indicating that they were better able to focus their attention away from the emotional meaning of the words and to instead concentrate on the color. Since inability to focus is one of the main symptoms of depression, the implication is that in the real world depressed people who find themselves in a state of chronic worry are, in at least one narrow sense, better off.
Says co-author Gregory A. Miller, "Sometimes worry is a good thing to do. Maybe it will get you to plan better. Maybe it will help you to focus better. There could be an up-side to these things."
The nice thing about this finding is that, unlike the earlier paper, you don't have to wait until the end of your life to enjoy the benefits of a longer life span -- you can savor your extra powers of focus and attention right now. The drawback is the same, though: in order to enjoy the benefits of worry, you have to be depressed in the first place.
