Depression is a real and (potentially) serious condition that is thought to involve chemical changes in the brain. It involves both emotional and physical symptoms that can have a major impact on a person's life.
Causes of depression
It is known that chemical changes in the brain contribute to producing the symptoms of depression.
Depression is thought to be associated with changes to the levels of three principal chemicals in the brain that control a variety of body processes including:
- serotonin – mood, appetite and going to sleep
- noradrenaline (also called norepinephrine) – mood, waking and attention/concentration
- dopamine – movement, motivation, and experiencing pleasure
If the levels of these chemicals are upset, this can lead to medical problems, such as depression.
Another chemical that may play a role in depression is cortisol – the 'stress hormone' – which helps the body and mind cope with stressful situations. High levels of cortisol have been observed in some people affected by depression, although the exact link between cortisol and depression is not known. Many of the medications used to treat depression work by helping to return the levels of chemicals in the brain back to normal.
Risk factors for depression
Depression can affect anyone – in some people it occurs without any apparent reason or warning, while in others, factors known to make them more vulnerable to the condition play a role. These include:
A question that is often asked about depression is, "Can it be inherited – is it 'in the genes'?" Genes do appear to play a role in depression in some cases, and there may be a family history of the condition. However, it is not a simple connection, and many genes are thought to be involved. So if one family member is affected by depression, it does not necessarily mean that their relatives will develop the illness too.
Social and environmental factors
No single event in a person's life will, on its own, lead to depression. However, in some people, certain experiences or circumstances may act as a trigger for the condition.
For example, unpleasant events may trigger depression e.g.:
- physical/emotional abuse
Alternatively, ongoing circumstances may be involved, e.g.:
- financial stress
- health issues
- lack of intimacy
- prolonged unemployment or retirement
Immigrants, refugees, and others who have had to move away from their familiar surroundings may also be at greater risk of developing depression.
Whether a person will develop depression can depend a great deal upon their life experiences.