Depression in older people is a major public health problem and is often associated with physical illness. However, it is unclear whether it is the illness itself that causes the depression i.e. there is some physiological link between the illness and depression - or whether it is the effects of the illness, in terms of pain, discomfort and restricted functioning that makes people depressed. A Singaporean study of 2,611 people over 55 looked at the links between physical illness and depression. The researchers found that high blood pressure, eye problems, diabetes, arthritis, heart disease, asthma, stroke, osteoporosis, heart failure, thyroid problems and gastric problems all raised the risk of depression. However, once people's feelings about their illness and their restricted functioning were taken into account only asthma, gastric diseases, arthritis and heart problems were found still to be linked to depression.
Niti, Matthew ... [et al] - Depression and chronic medical illnesses in Asian older adults : the role of subjective health and functional status International Journal of Geriatric Psychiatry November 2007, 22(11), 1087-1094