The prevalence of major depression is estimated at 2-3% in adults of all ages. Depression can affect people's cognition, in particular information processing, memory and executive functions and this effect is particularly pronounced among older people. However, it is not known whether this effect of depression on cognition is due to the particular nature of late-life depression, or to the general effects of the aging process on people's mental abilities. Researchers from Newcastle University in the U.K. compared the cognition of 157 people with and without depression. Within the two groups half of the participants were over 60 and half under. The study found that those people who were depressed and over 60 had more problems with verbal learning and memory and coordination, but not with executive functioning. The researchers concluded that 'late-life depression is associated with more severe impairment in verbal learning and memory, and motor speed than depression in earlier life and this is not due to ageing alone.'
Thomas, A.J. ... [et al] - A comparison of neurocognitive impairment in younger and older adults with major depression Psychological Medicine May 2009, 39(5), 725-733