How Depression Can Affect Your Memory Functions

Forgetting? You May have Depression

One often unrecognized indicator of Depression is diminished cognitive function including attention, memory and executive functioning. Cognitive symptoms of Depression can have a profound effect on a person’s ability to manage the demands of everyday life. Forgetfulness, “absent-mindedness” and an increased incidence of misplacing things can be a sign of depression.

Other indicators of Depression may be obvious (crying, apathy, isolation), however, those who begin to forget things, get “turned-around” while driving, lose their keys, or forget appointments may not recognize that they are experiencing elusive signs of Depression.

Studies of memory in depressed patients have consistently shown impairments in short-term recall and learning for both verbal and visual-spatial material.

A recent study by Finnish researchers with 174 adults with major depression showed the significant impact of Depression on cognitive memory skills. “At the start of the study, the depressed patients performed poorly on several neuropsychological tests of memory, including the ability to repeat short stories or lists from memory. For the next six months, the patients were given treatment for their depression, including medication and/or therapy. At the end of this period, patients whose depression had been reduced also reported fewer memory problems. Their performance on the memory tests also improved.”

Scientists are researching the connection between depression and memory-some in hopes of improving treatments, others to improve understanding of the deep connections between mind, mood, and memory. Using brain imaging techniques, they can document differences in executive brain functions - between healthy brain functioning and those with Depression. Scans of “Depressed” brains exhibit imbalances in the chemicals, called neurotransmitters that enable individual brain cells to communicate or connect to each other, thus inhibiting the storage of new memories. Many studies, for example, have shown that brain-cell activity in the frontal lobes-located in the front of the brain, behind the forehead-is often reduced in depressed people. Part of the explanation for this may involve a brain chemical called serotonin. Among other things, serotonin regulates blood flow, providing cells with the fuel they need to operate. Blood flow in the brain can be monitored indirectly with a medical imaging technology called positron emission tomography (PET).

Depressed people generally have decreased levels of serotonin, which may explain the reduced brain-cell activity. Additionally, serotonin is involved in regulating arousal-the ability feel interested in or stimulated by normally pleasurable activities. The new “second-generation” antidepressant drugs, selective serotonin reuptake inhibitors (SSRIs) and monoamine oxidase (MAO) inhibitors, increase arousal by boosting the amount of available serotonin in the brain.

“One of the ways that depression affects memory is by skewing the types of memories people tend to recall while in the grip of melancholy. We all tend to remember happy events when we are happy and sad events when we are sad, explains Norman Rosenthal, MD, a professor of clinical psychiatry at Georgetown University Medical School. A depressed person tends to recall mostly the negative, unhappy experiences. This can appear to family and friends as a loss of memory. It also reinforces the person’s drab and negative view of life, fueling the depression.”

Coordination of memory is also affected by the chemical imbalances in the depressed individual.

Depression impairs the ability to create long-term memories. “It really comes down to a lack of attention and concentration,” explains Constantine Lyketsos, MD, director of neuropsychiatry at the Johns Hopkins School of Medicine. “For example, a depressed man agrees to meet a spouse or friend at a certain address. An hour later, he realizes he has “forgotten” the address. But perhaps due to a lack of attention and concentration-a hallmark of the depressed mental state-he never really formed an enduring memory of the address in the first place.” This type of event reflects a loss of coordination or linking-between the working, short-term, and long-term memory.

The Bottom line: treat your Depression, improve your memory!

Further Reading:

“Mood improvement reduces memory complaints in depressed patients,” by R. Antikainen and others, in European Archives of Psychiatry and Clinical Neuroscience, 2001, vol. 251, pp. 6-11.

“Changes in cognitive functioning following treatment of late-life depression,” by M. Butters and others, in American Journal of Psychiatry, December 2000, vol. 157, p. 1949-1954.

“Imaging strategies in depression,” by P. Grasby, in Journal of Psychopharmacology, December 1999, vol. 13, no. 4, pp. 346-351.

If you or someone you know may be suffering from depression, contact the National Alliance for the Mentally Ill (NAMI) can point you to local affiliates that can guide you to treatment resources in your area. Write to: 2107 Wilson Boulevard, Suite 300, Arlington, VA, 22201-3042. Tel: 800-950-NAMI. Or browse the web: http://www.nami.org.

The National Institute of Mental Health will also send you free information about depression and its treatment. Contact the Information Resources and Inquiries Branch, 800-421-4211. On the web, browse http://www.nimh.nih.gov.