Depression is very common – UK prevalence is estimated at 4.5 per cent – and is the leading cause of disability and premature death in people aged 18-44 years. 

The cause of depression is unknown, but it seems likely that biological, psychological and social factors interact. Certain factors appear to increase the risk of the condition developing, including chronic illnesses such as diabetes, chronic obstructive pulmonary disease (COPD), cardiovascular disease and anything causing long-term pain; medicines such as corticosteroids; genetics; and life events such as bereavement, divorce, unemployment, poverty, homelessness and adverse childhood experiences. Women, particularly those who have recently given birth, are also at higher risk.

Depression is more than just someone feeling low in mood. The pain and disability of physical diseases can be exacerbated and can lead to increased morbidity and mortality, for example, there is a higher rate of amputation in people with diabetes who also have depression. Depression can also lead to an impaired ability to function normally, which can impact on work
and relationships, and an increased risk of substance abuse and/or suicide.