Late-life depression and cognitive impairment before and after SSRI treatment: A neuropsychological study
Depression and cognitive impairment, especially in the elderly, are widespread and costly problems. Depression has been found in 10 to 35% of the elderly population, and rates continue to rise (Blazer, Hughes & George, 1987). Prevalence rates of cognitive impairment in the elderly have been reported to be between 10 and 40%, showing higher risk as age increases (Hanninen et al., 1995). One question that plagues clinicians and researchers alike is what neuropsychological changes occur after antidepressant treatment. Knowledge abounds comparing depressed patients to non-depressed patients, and cognitively impaired patients to cognitively intact patients. Though the previous research has yielded some general information, longitudinal treatment studies are lacking. ^ The purpose of the current study was to investigate longitudinally the neuropsychological changes that occur as a result of antidepressant therapy among a group of elderly depressed adults. This population has special needs as it is susceptible to neurodegenerative disorders. In this study, a comprehensive neuropsychological evaluation was conducted at baseline and eight-weeks, which formed the basis of this study. The specific areas of investigation included: recall versus recognition, encoding/learning versus delayed recall, the influence of psychomotor speed, and visual versus verbal recall. In showing the changes that occur with successful antidepressant treatment, this study aimed to clarify which neuropsychological deficits are more associated with depression, rather than with neurodegenerative changes. Ultimately, this study attempted to better explain the cognitive syndrome associated with depression in late-life. ^ The responder and non-responder groups did not significantly differ on any one of the neuropsychological measures prior to treatment. Moreover, there were no baseline differences between the groups on level of depression based on the Hamilton Depression Inventory. This lack of baseline difference on neuropsychological and depression measures highlights the grave dilemma of clinicians who treat depressed elderly patients with cognitive difficulty. ^ The results of this study show that more in late life depression and cognitive impairment, cognitive resources are taxed, and the more cognitively demanding tasks showed greater treatment-resistance. Overall, recognition improved significantly whereas verbal free recall did not; learning new material (a cognitive labor-intensive activity) showed no change in response to treatment; and psychomotor speed/activation was significantly related to verbal recall (at trend level) and visual recall; finally, the only significant difference was between verbal and visual recognition, where visual (more difficult to remember) was significantly lower than verbal memory. Although the originally hypotheses supposed that visual recall would improve more than verbal because it was more difficult, the logic was flawed because it expected the most change on the most difficult tasks. The current study shows that patients whose depression is improving enough for them to begin to perform their daily activities may not be ready to produce more correct results spontaneously, but they will be better able recognize correct responses when they see them. Results imply that psychomotor activation, and/or motivation may be major factors in the improvement of cognitive functioning after antidepressant therapy. ^
Gerontology|Psychology, Clinical|Psychology, Cognitive
"Late-life depression and cognitive impairment before and after SSRI treatment: A neuropsychological study"
(January 1, 2006).
ETD Collection for Fordham University.