Trying to remember a grocery list or a phone conversation isn’t always easy. And it turns out, there are certain thoughts that may make these types of tasks even harder.

Depressive thoughts – like ‘I’m not good enough,’ or ‘I’m unattractive’ – can have an impact on memory.

Here’s what we already know about memory and depression:

“People who are depressed report problems with their thinking, especially short term memory,” says Bart Rypma. Rypma is associate Professor in Behavioral and Brain Sciences at UT Dallas and with the Center For Brain Health.

“But what’s also known is [researchers] haven’t been able to observe [short term memory problems] in the behavioral laboratory,” he says.

So, Rypma recruited 157 students, and ran a study — the results are published in the journal Cognition and Emotion. He classified the undergraduates into two groups – those with mild depression and those without…then, participants from both groups sat in front of computers and responded true or false to sentences like…

“I am incapable,” “I’m incompetent,” “I am sad,” or “People don’t like me.”

Then the students are hit with a list of items to remember — like a string of numbers.

“What we observed,” Rypma says, “Was that when people had been exposed to the depressive thoughts, the depressed individuals performed worse.”

Brain Space And Depression 

In summary, the people who were depressed and then exposed to sentences with depressive thoughts had more trouble remembering numbers and lists.

Why? Rypma thinks the answer has to do with brain space…

“When you are exposed to a depressive through it displaces space in your short term memory so there isn’t space to process a list of items to remember,” he says. “That space is taken up by ruminating on a depressive thought.”

So, Rypma says depressive thoughts aren’t just distracting, they’re preventing individuals from forming new memories.

Depression affects millions of Americans and costs billions of dollars in lost productivity. Rypma says better understanding the link between memory loss and depression is key to developing new therapies.

The next step is studying individuals who meet the clinical diagnosis for depression.