Cognitive Impairment and Depression Outcomes in the IMPACT Study

Abstract

It is unclear whether cognitive impairment affects acute and long-term treatment response in geriatric depression. In addition, little is known about the long-term outcome of depression among older individuals who experience cognitive decline during a course of treatment for depression. The authors examined both of these issues using data from the IMPACT trial. The sample consisted of 1,684 participants in the IMPACT study who had baseline and two-year follow-up data. Subjects were randomized to one year of active intervention with a depression care manager or usual care. After one year, all subjects had usual care for another year. Data were collected for two years. The authors used the Six-Item Cognitive Screener to examine acute and long-term effects on depression outcome of baseline cognitive impairment and of cognitive decline. Depression measures included the HSCL-20 and an estimation of depression-free days. Outcomes were determined using both linear regression and repeated-measures analyses. Depressed subjects in the active intervention group had better depression outcomes at one year regardless of baseline cognitive impairment. Cognitively impaired subjects within each treatment group had similar outcomes to subjects without cognitive impairment. Subjects who experienced decline in cognitive score over two years had worse 24-month depression outcomes compared with subjects whose cognitive score did not change. Cognitively impaired depressed patients can experience significant improvement in depression with appropriate acute and continuation-phase management. Older depressed adults experiencing ongoing cognitive decline may be at higher risk for poor depression outcomes and may require more careful clinical monitoring and management of both cognitive and affective symptoms.