What is Depression?Depression is a word often used to describe our feelings. Everyone feels gloomy or fed up from time to time. Such feelings are a normal part of the emotional ups and downs of life. But true depression is something else altogether.
One way to understand the distinction is to think of mood and emotions in terms of the climate and weather. The climate sets the broad framework within which the weather varies but it doesn’t change that much from what you’d expect. In the same way, the mood sets the framework within which emotions operate. A disorder, like depression affects mood, and is similar to radical changes in the climate rather than emotional outbursts, which stem from particular problems and are usually short–lived.
The core symptoms of depression are:
- Lowered mood.
- Loss of energy and interest.
- A feeling of physical illness or of being rundown.
- Poor concentration.
- Altered appetite and sleep.
- A slowing down of physical and mental functions.
But its probably the relentless feeling of hopelessness, helplessness, guilt and anxiety that also accompany which are the most difficult to cope with. One indication of the depths of despair experienced by sufferers is the fact that depression is the most common cause of suicide. Should you experience symptoms like the ones mentioned above, you are advised to discuss this with your doctor.
What causes depression?The exact cause of depression remains unclear. The most probable explanation, and the one on which treatment with antidepressant drugs is based, is that it is an imbalance in certain chemical messengers (also called neurotransmitters) in the brain. The neurotransmitters, of which there are about 30, transfer messages between nerve cells in the brain. Some evidence suggests that depression is caused by a deficiency in two neurotransmitters called noradrenaline and serotonin. But if depression is caused by an imbalance in these neurotransmitters, what triggers it in the first place?
There is growing interest in genetic approaches to understanding a variety of diseases and depression is no exception. Some people certainly seem to be more vulnerable to depression than others and there is growing evidence that some genes could make individuals susceptible to the disease. This would also explain why depression often runs in families. Some studies have shown that people who have relatives with depression have a 1 in 4 chance of developing it themselves, compared with only 1 in 14 for the general population. Recently, scientists at Edinburgh University identified a gene which increases the risk of depression by four times and confers susceptibility to depression in more than 10 percent of people affected. The gene is known to code a protein involved with the transport of serotonin in the brain which ties with the pharmacological explanation of depression. But any complete genetic understanding of this illness is a long way and researchers estimate there may be as many as 30 other depressive genes involved.
However, in most cases, just having these genes is probably not enough to cause depression on its own. Stressful situations can exacerbate this vulnerability. Depression can be triggered by a number of factors such as unemployment, bereavement, social isolation or even a severe physical illness.
But while it is important to recognize the role that these triggers can play in the development of depression, it is also important to acknowledge that in some instances depression strikes completely out of the blue for no obvious reason. While this might seem harder to understand for both the sufferer and those around them, this type of depression is no less difficult to deal with or worthy of help.
How common is depression and who gets it?Depression is one of the most frequently occurring mental illnesses or the ‘common cold’ of psychiatry. In 1996, the Director General of the World Health Organization estimated that 340 million people suffer from mood disorders worldwide. Depression is the second most common mental illness after anxiety, but the most common serious mental illness.
Epidemiological studies report a lifetime risk of developing depression of between 8–12 per cent for men and 20–26 per cent for women (Arch Gen Psychiatry 1981 38:10391046).
In many studies, a further 8 to 20 per cent of community samples report depressive symptoms that do not meet the threshold for major depression but nevertheless cause increased mortality, disability and poor social functioning.
Who is at high risk?No one is immune from depression: it occurs in people of all ages, all social classes, all countries and all cultural settings.
Women are twice as likely to develop depression as men. Many explanations have been suggested, but psychosocial factors would appear the most likely, e.g. the greater stress on women of maintaining multiple roles such as homemaker, professional wife and mother.
The risk of depression was thought to increase with age, but recent studies now show the average age onset has dropped from the late 40s to the late 20s since World War II (JAMA 1996 276:293299).
Rates of depression decline with increased income and education. More severe forms are also associated with lower socioeconomic status (Arch Gen Psychiatry 1994 51:919).
Depression is two to three times more common among the family of depressed patients. About 20 per cent of relatives of depressed individuals are affected compared to 7 per cent of relatives of controls (Arch Gen Psychiatry 1982; 39:13971403).
Separated or divorced people have a two to four times greater risk of depression than married. Divorced or separated men seem to be at higher risk than women.
Depression in the elderly
Depression is common among the elderly, although it often goes undetected and untreated in this patient group. Estimates of prevalence are about 15 per cent and depression is twice as common in those suffering from physical illness. Depression is also associated with high chronicity and a considerable risk of relapse and suicide in the elderly. Elderly sufferers display more vegetative signs such as insomnia, fatigue, constipation and weight loss, rather than sadness or dysphoria. Cognitive disturbances are also often misattributed to physical illness, dementia or the ageing process itself.
What about children?In the last 20 years depression is increasingly being recognized to affect children and adolescents. Children from a broken home, who have lost a parent early in life, suffer from neglect or live in inner–city areas with high rates of poverty, unemployment and crime are more vulnerable to depression.
Depression in childhood can lead to impaired school performance, poor relationships, and increased tobacco and substance usage.