Professor Finds that Repeated Episodes of Major Depression Can Lead to Memory Loss

Tuesday, November 30, 1999

A study of patients hospitalized for major depression finds that people with recurrent episodes of this mental illness suffer significant memory loss, prompting questions about the ability of such individuals to function normally after their discharge, according to study leader Michael Basso, a psychology professor at The University of Tulsa.

“Because of forgetfulness, recurrently depressed individuals may have difficulty attending to their daily affairs in an effective manner,” says Basso.

Memory tests were administered to 66 patients whose primary diagnosis was major depression. For 20 of these patients, it was the first time they had been hospitalized for the condition, and for 46 it represented a recurrent episode.

Basso says memory abilities were near the norm for the single-episode group, but for those with recurrent episodes, memory was far worse than what would normally be expected.

To evaluate memory function, subjects were read 16 words from a simulated grocery store shopping list and then were asked to recall as many of the words as possible. The recurrently depressed individuals remembered fewer words than the patients who were depressed for the first time.

According to Basso, the findings imply that memory problems may increase during the course of the illness. The only difference in personal characteristics between the two groups was whether individuals had a history of a single episode of major depression or two or more episodes. Basso says the data suggest that as a person has numerous depressed episodes, memory dysfunction may worsen.

Results of the study were published in the October 1999 issue of the journal “Neuropsychology.” The article, “Relative Memory Deficits in Recurrent Versus First-Episode Major Depression,” was written by Basso and Robert A. Bornstein of The Ohio State University Medical Center.

Basso says a second study of 43 patients hospitalized for depression, including 41 experiencing a recurrent episode, found that as the number of years increased since the person’s first hospitalization, memory loss worsened. This study was conducted at the Hennepin County Medical Center in Minneapolis with Paul Marshall, a clinical neuropsychologist at the center. Results were presented at the annual meeting of the International Neuropsychological Society in Boston in February.

Basso notes that memory loss is one of the most common complaints of people affected by depression. He also says that one of the best predictors of who will sustain an episode of major depression is a previous episode.

Major depression often leads to severe despair and hopelessness, causing the person to lose interest in life. The symptoms affect one’s ability to work, sleep, eat and enjoy pleasurable activities. The American Psychiatric Association says up to 15 percent of people with major depression die by suicide.

The APA says studies have found that the prevalence of major depression in adults in community samples has varied from 5 to 9 percent for women and 2 to 3 percent for men. The National Institutes of Mental Health says more than 19 million adults in the United States will suffer from a depressive illness, including major depression, this year.

Basso is a clinical neuropsychologist whose research involves cognitive function in patients with psychiatric disorders, immune disorders and multiple sclerosis.