Change in cognition during antidepressant treatment of late life depression

Cognitive impairment is common in late life depression. A large US study of the prevalence of major depression found the rate to be 9.1% in indiviudals over 60 years of age (Kessler RC et al JAMA 2003). The US Census Bureau projects there will be 59,710,000 people in the US over the age of 65 in 2022. That translates into 5,433,000 individuals with lifetime major depression. Late life major depression contributes to disability and is an estblished risk factor for further cognitive decline and dementia. Both psychotherapy and antidepressants have been used to treat depression but their relative effectiveness for improving cognition has not been well studied. The field has assumed that if depression is treated successfully, cognition will return to normal, but this is not true. We have performed a systematic search of the literature. 640 citations were intially identified. From this group we found 7 studies with 11 contrasts of 7 antidepressants. Duloxetine was the most commonly studied. Some antidepressants had little effect on cognition (e.g. nortriptyline, paroxetine, citalopram). Duloxetine, vortioxetine, and sertraline had the greatest effects. However, almost all of these studies had incomplete data presented. Understanding which antidepressants have beneficial effects on cognition is crucial to the treatment of depressed patients who are cognitively impaired and may be important in reducing the risk of further cognitive decline.