Antidepressants Improve Some Seniors' Cognition
Successful antidepressant therapy improves, but does not restore to normal, the ability of elderly patients to remember people and events and solve problems, a new study finds.
This improvement, reported in the December 2000 American Journal of Psychiatry (PDF), occurred only in the patients who initially had some degree of cognitive impairment. Patients who initially had a normal level of cognitive functioning did not improve in mental ability when their depression responded to treatment.
Researchers conducted the study between June 1996 and December 1998 at the outpatient psychiatric unit of a Pennsylvania teaching hospital. The elderly adults who participated in the study received nortriptyline or paroxetine to treat their depression.
Sixty-two seniors with a diagnosis of major depression were assigned to the treatment groups, and an additional 20 elderly adults without symptoms of depression served as the control group. The research team based its main findings on data from the nine men and 36 women whose depressive symptoms abated after treatment.
Among these 45 seniors, 10 were initially classified as cognitively impaired on the basis of their scores on a widely used brief mental status test of cognitive function. The remaining 35 elderly adults had no cognitive impairment when they started antidepressant therapy.
The researchers used a battery of diagnostic psychiatric tests to evaluate the study participants initial mental status. Study enrollees also underwent a physical examination, which, for the patients with depression, included magnetic resonance imaging (MRI) scans. Less-extensive mental and physical evaluations were done after the patients depressive symptoms abated, which usually occurred after 12 to 14 weeks of treatment.
Seniors who had signs of cognitive impairment at the start of the study were on average 79 years of agesignificantly older than the unimpaired and control groups. The poorly functioning seniors had an average of 9.2 years of education, compared with 12.2 years for the unimpaired group and 13.1 years for the control group. There was no significant difference between the two treatment groups in the age at which depressive symptoms began to appear.
The study analysis did not discuss the results of the patients MRI scans or other physical or laboratory tests. Using information from other published reports, the researchers suggested that their patients' cognitive impairment likely resulted from physical changes in their central nervous system, which made the seniors vulnerable to the "toxic" effects of depression.
Because of a reported association between physical changes in the brain and dementia diseases, the researchers suggested that depressed seniors with cognitive impairment are likely at high risk for progressive dementia.