We currently diagnose depression based on what individuals tell us about their feelings – or those of their loved ones. People with depression usually describe feeling sad or say they are unable to enjoy the things they used to. But in many cases they don’t actually realise that they are clinically depressed – or feel uncomfortable talking to a health professional about it.
Such cases pose an important problem as untreated depression can hugely interfere with someone’s life, significantly increasing the risk of suicide. Currently, it is difficult to help people who are not able or willing to communicate how they feel, as there are no biological markers for the condition. But we have managed to identify a network of brain regions that is affected in people with depression – raising hope that brain scans could soon be used to diagnose it.
Depression has been recognised as an illness for centuries and was initially called melancholia – then believed to be caused by an excess of “black bile”. We now recognise that there are genetic as well as environmental factors that increase the risk of depression. For example, it occurs more frequently in certain families and in children who have suffered from abuse. We are also beginning to identify genes that are associated with the development of depression.
There are several physical symptoms of depression, including a reduction in appetite and weight loss. But the trouble is that these could be caused by a variety of conditions. Also, people can be affected in different ways – some may notice an increase rather than a decrease in appetite, for example.
Problems with sleep are also common. Many people wake up in the middle of the night and then have trouble getting back to sleep. Others may be sleeping more than they usually do. Further symptoms include losing interest in doing things, a reduction in libido, a lack of energy and finding it difficult to concentrate. Some people start over-thinking things, feeling guilty or even begin to wish they were dead.