People with depression get stuck on bad thoughts because they're unable to turn their attention away, finds a new study.
Such people keep brooding over a fight with a friend, a divorce or the loss of a parent. Though a majority of the population is able to pull out of the negative thoughts caused by these situations, some fail to do so.
This leads them to develop major depression.
"They basically get stuck in a mindset where they relive what happened to them over and over again," said Jutta Joormann of the University of Miami.
According to Joormann and her colleagues, people with depression might have a problem with working memory, which refers to what thoughts a person keeps active in his/her mind.
The researchers recruited 26 people with depression and 27 people without the condition. Each person was made to sit in front of a computer and shown three words, one at a time for a second each.
They were told to remember the words either in the order they were presented or in backward order. The faster they were able to give a correct answer, the better they were at thinking flexibly.
It was found that people with depression had trouble re-ordering the words in their head.
If they were asked to remember the words in reverse order, they took longer to give the correct answer. They had a particularly hard time if the three words had negative meanings, like "death" or "sadness."
"The order of the words sort of gets stuck in their working memory, especially when the words are negative," Joormann added.
The study will be published in an upcoming issue of Psychological Science.