Many people around the world suffer from depression. Though depression can be extremely debilitating, evidence-based treatments (like cognitive-behavioral therapy) provide hope, because they can be very effective in treating the negative thinking that accompanies depression.
Still, many people who recover from depression relapse later on. The reasons may be varied, but a new study suggests one possible contributor: Formerly depressed people dismiss positive emotional content too easily and hold on to negative content too strongly.
“This may be one of the reasons why people who’ve had depression ruminate over and over again about things that happened in the past,” says study coauthor Lira Yoon of the University of Maryland, Baltimore County.
The grip of negativity
Researchers analyzed findings from 44 studies in which over 2,000 formerly depressed people were tested on how well they processed emotional information (in comparison to people who’d never suffered from depression).
In each study, participants had to recall either emotional faces or emotional words correctly. For example, in some studies, participants were presented with a series of faces expressing happy, sad, or neutral feelings, then asked whether a new, unfamiliar face had the same expression as one they’d seen two faces earlier. In others, participants were asked to memorize a list of emotionally laden or neutral words (such as war, peace, and chair)—with some printed in red ink and some in blue ink—and later asked to recall just the words written in blue (or red). Though there were many different tests used in different studies, all required participants to let go of irrelevant emotional content in favor of relevant content to do the tasks at hand.
The researchers found that people in recovery from depression had more trouble processing all emotional information, which meant it took longer for them to do the tasks. In particular, they had greater difficulty discarding irrelevant negative information than irrelevant positive information; in other words, they held on to negative information when it wasn’t useful and forgot positive information when it was.
Yoon says this suggests people remain vulnerable to a negativity bias even after they’ve recovered from depression.
“They’re still having difficulty ignoring irrelevant negative information that’s not helping them; so, in some sense, their mind is crowded with negative information,” says Yoon. “That could definitely increase their risk for relapsing or having another depressive episode.”
What might this look like in everyday life? Suppose you have an argument with a spouse or family member in the morning, says Yoon. You might have more trouble letting go of negative comments or criticism lobbed at you during the argument. Later on, if you have a conversation with a work colleague, where the negativity from your earlier argument has no relevance, you may not be able to pay attention or get what you need from the conversation—you’ll be too distracted.
“You may have a hard time getting rid of the earlier argument, and negative comments or criticism you received keep popping into your mind,” says Yoon. “That’s not relevant to what you’re talking about right now, so you shouldn’t be talking or thinking about it.”
Who is susceptible to this after depression? You might expect someone’s heightened negativity bias to be affected by how severe and frequent their past depressive episodes were, or whether they use anti-depressants. But Yoon and her team didn’t find evidence for that. Nor was there a difference between women and men, despite women being more prone to depression. No matter the situation, the tendency for a strong negativity bias appeared to endure.
However, Yoon believes these factors may still be relevant, even though she didn’t find evidence for them. Not all of the studies she used in her analyses provided the information needed to test these factors, and so future research is needed, she says.
How to manage negativity bias
Though Yoon’s study didn’t speak directly to solutions, she encourages formerly depressed people to be more deliberate in letting go of negative information. For example, mindfulness exercises can be useful, she says, because they teach us to focus on the present moment without judgment and to let go of irrelevant information from the past.
It’s also a good idea for formerly depressed people to consider limiting how much time they spend reading negative news of the world, Yoon adds. Otherwise, they may end up in negativity loops that reinforce their depression—and make it even harder for them to benefit from social encounters.
“If we only access negative information or memories, that’s going to make us think every new situation will be awful—maybe a person won’t like me, or I won’t have fun with this person,” she says. “When we expect negative things to happen, we act in a way that actually elicits negative responses from other people, confirming our expectations.”
Adding more positive emotional experiences into your day may also help “crowd out” negative thinking patterns, she says. For example, you can set up fun things to do with friends or simply practice more random acts of kindness for people around you—something that should help you feel better about yourself and get more positive reactions from others.
A previous study backs up this idea: When depressed and anxious people added deliberate, kind acts to their lives, it was as effective at reducing their symptoms as challenging negative thoughts or adding social activities (two common ways to help with depression). And practicing kindness had the added benefit of making people feel more socially connected, which is often a problem for depressed people.
Though Yoon has not studied these kinds of activities herself, fostering other positive emotions and thoughts may also help people reduce their negativity bias. For example, gratitude and self-compassion exercises can both help depressed people ruminate less, suggesting they may also be useful for those who’ve suffered depression in the past and can’t let go of negative thinking.
Though more research is needed, Yoon hopes that her findings help point a way forward for those who are vulnerable to depression relapse. It does no one any good to stay stuck in negativity loops, she says, so taking action to avoid that is important for well-being, for everyone.
“If we are preoccupied with negative information, we cannot function well,” she says. “We all need to make room for the positive information coming our way.”