Depressed but decisive, anxious and paralyzed

While anxiety reduces the ability to choose words, depression is associated with better performance in word selection, CU-Boulder-led study finds

Depression and anxiety are often mentioned in the same breath, and for good reason. About half of those with a history of depression also have a history of anxiety, and both are associated with impairments in a person’s “executive function.”

Hannah Snyder likes to think of the human brain’s executive function as akin to an executive of a company who is constantly choosing between many options.

"Depression is not usually associated with cognitive benefits, but Hannah found that depressive symptoms were associated with better abilities to choose between options.”

“Executive function is talked about in popular media as if it were one thing,” says Snyder, who earned a Ph.D. in cognitive neuroscience from the University of Colorado Boulder in 2012 and is now a postdoctoral fellow at the University of Denver.

“It’s not. It’s a collection of abilities that allow you to control and direct your behavior to accomplish your goals.”

Research has shown that the more choices your brain’s CEO has, the harder it is to make a decision. That goes not just for choosing among scores of breakfast cereals at the grocery store but also how we choose words when speaking.

“Though you are not consciously aware of it, you are constantly choosing between a lot of different words. This does slow us down,” Snyder says.

Now, in groundbreaking new research, she has found that where anxiety reduces the ability to choose words, depression is surprisingly associated with better performance in word selection.

Despite their frequent comorbidity, “Anxiety and depressive symptoms counterintuitively have opposite effects,” Snyder writes in the journal Cognition and Emotion.

“Depression is not usually associated with cognitive benefits, but Hannah found that depressive symptoms were associated with better abilities to choose between options,” says Yuko Munakata, professor of psychology and neuroscience at CU-Boulder, Snyder’s former adviser.

“These findings are important in highlighting the distinct cognitive profiles associated with anxiety and depressive symptoms.”

The explanation for the difference may lie with the neurochemistry of the brain. Word choice occurs in prefrontal areas of the brain involved with executive function, where glutamate and GABA, which serve as the main excitatory and inhibitory neurotransmitters, respectively, exist.

Previous research has demonstrated that GABA’s inhibitory mechanism does not work as well in patients with higher levels of anxiety, Snyder says.

“All those different words are active in the brain all at once, shouting ‘Choose me, me, me!’ GABA is sort of hushing everyone down until there is just one voice left. The winner is the word you pick,” she says.

Conversely, depression is associated with lower levels of excitatory glutamate.

“In Hannah’s framework, (a) reduction in the excitatory function leads to reduced activity of competing responses and improves the ability to select one option,” says Munakata, a co-author of the paper.

Snyder notes that the study doesn’t specifically examine that hypothesis. But she is co-author with CU-Boulder graduate student and lead author Alejandro de la Vega and Professor of Psychology Marie Banich on a paper to be published in the Journal of Cognitive Neuroscience based on research that directly measured ratios of glutamate and GABA using spectroscopy.

“This is more direct evidence that nicely backs up” the anxiety-depression model she has developed, Snyder says.

Some people, including peer reviewers at academic journals, have asked Snyder if she’s saying depression is a good thing.

“No, depression is not good for you,” she says.

But the research may have implications for treatment of anxiety and what kinds of therapy are done. For example, patients with anxiety might do better when presented with a limited number of choices rather than an open-ended decision such as, “What are you going to do this weekend?”

“Social anxiety might keep someone from going out, so saying, ‘OK, here is a list of social activities, pick three before next week,’ might be more effective,” Snyder says.

Clay Evans is director of public relations for CU Presents.