Depression in physical illness.

The diagnosis of depression in patients with physical illness is challenging. Symptoms of depression occur commonly but it is not always clear when they merit clinical attention. Depressive illness is more prevalent in patients with medical conditions than in the general population and results in substantial disability and healthcare costs.1 Despite this, there remains a perception that depression is an ‘understandable’ reaction to a serious illness. It is, however, usually treatable and, as well as improving mood, treatment may reduce somatic complaints.