There are many possible causes of depression. You may have an increased risk of experiencing depression because of your particular biological make-up. On the other hand, depression is also related to what is happening in your life, and the kind of support you receive from others.
Is depression inherited?
There is some evidence that depression seems to run in families, but there is no single gene which causes depression.
A family history of depression may increase the risk, but this may be because of difficulties the family has in coping, and it certainly does not mean that depression is inevitable. Genes seem to be more important than childhood experiences in determining the risk of bipolar disorder.
Is depression caused by changes in the brain?
We know that depression is associated with changes in the activity of certain brain chemicals, known as neurotransmitters, which affect our mood and thinking. These chemicals, such as serotonin, are also affected by factors such as activity and exercise. Drug treatment aims to restore ‘normal’ levels of neurotransmitter activity.
What about childhood experiences?
Past experiences which may be difficult or traumatic, such as losing a parent when very young, can affect your ability to cope with difficult situations. Children who experience abuse or lack of affection are also more at risk of experiencing depression in later life.
What about stress?
An episode of depression can be ‘triggered’ by stressful things that happen in our lives, particularly events involving a loss of some kind – such as unemployment, leaving home, death of a family member or friend. Even an apparently happy event can also bring a sense of loss; for example, parents can feel they have ‘lost’ their son or daughter when they get married, even if they are very happy for them. If you have had to cope with a lot of changes or stressful events, one more may seem like the ‘last straw’.
Older people often have to cope with repeated losses, including the death of close friends and family. There is an important difference between expressing grief – which is a healthy reaction to loss or bereavement – and depression.
Men living alone after the death of their wives seem to be particularly at risk of depression. Young people also experience stress, for example due to problems at school, starting work or a course of study, or problems with relationships. It can be quite difficult to tell whether a young person is going through ‘normal’ adolescent turmoil or is showing signs of depression.
Styles of thinking and coping
People who are depressed tend to think about bad experiences in ways that make them even more difficult to manage. If you have had bad experiences in the past, which you were unable to control, you may develop a ‘hopeless’ way of thinking.
Feeling ‘trapped’ in a difficult situation or experiencing a feeling of humiliation can also lead to negative thinking and depression.
This is why some forms of treatment aim to help you change your patterns of thinking.
Health & illness
We all tend to feel miserable when we are ill. But long-term health problems, which prevent someone from leading their usual life, may lead to depression. People who lose their eyesight or hearing can become depressed, as can people with heart disease, chronic lung diseases, and illnesses which prevent them from getting about, such as Parkinson’s disease or a stroke. Family and friends can help a lot by helping people find new activities or interests following illness.
Is it ‘normal’ to become depressed as we get older?
Some difficult life events may become more common with age, for example, children moving away, family illness or disability. Health or financial problems can also increase with age.
However, many people find that there are positive benefits of growing older, such as having more free time, being able to take up hobbies, or spend time with grandchildren. It is therefore wrong to assume that depression in older people is a ‘normal’ reaction to growing older, and it is important that severe depression is recognised, so that people can get the help they need.