WHAT IS IT?
We all feel a bit miserable or a bit low from time to time. This is common - even normal - but it is not what doctors describe as depression.

Clinical depression comes in many different forms, but it can include any combination of feeling miserable, negative thoughts, lack of interest and concentration, disturbances in your sleep and appetite, feelings of guilt and low self-esteem. Depression is often linked with anxiety. If you are severely depressed you may feel that life is not worth living, and may think about, or try to, kill yourself.

Nobody understands exactly what causes depression. Sometimes you will have a tendency to get depressed, and may suffer from depression on and off for no obvious reason. Sometimes depression is triggered by a very traumatic event or period in your life.

COULD IT HAPPEN TO ME?
Depression of some degree is very common - up to one in ten patients your GP sees will have symptoms of depression. You can get depression at any age, and you are more likely to get it if you are a woman. You may be at risk of depression if you have just gone through a very difficult time or life event. This can include bereavement, divorce, family, money or work problems.

Depression is remarkably common after childbirth, and not just when there have been problems with your pregnancy or delivery.

WHAT ARE THE SYMPTOMS AND DANGER SIGNS?
Depression can come on either gradually or suddenly. You will often find that you feel generally miserable, and that you tend to dwell on negative thoughts. Your mood may vary during the day, and you may wake early in the mornings and find it difficult to get back to sleep.

You may find it difficult to concentrate or to enjoy things you used to take a pleasure in. This will often mean that you avoid going out or socialising, and you may find that you find it hard to talk to people. You will feel anxious, irritable and sometimes very tired. You may burst into tears for no reason, or get into arguments or fights. You may feel guilty, perhaps about long-past events, and you may feel that life is no longer worth living.

Frequent feelings of guilt are danger signs in depression, but having suicidal ideas or actually making plans for suicide are even more serious. If you have these feelings, you should seek medical help urgently - see section below - Where can I get help?

HOW CAN I HELP MYSELF?
If you are feeling low or miserable for any length of time, you should make sure that you talk to someone about it. This need not be someone medically qualified - a spouse, family member or close friend can be invaluable. There are several voluntary phone lines you can call - see "Useful contacts" below.

If you have symptoms of clinical depression (see above), you should make an appointment with your GP. He may refer you for counselling, or give you ideas on where you can seek further help. He may also recommend tablets, which are safe and not addictive.

If your depression relates to a particular event, you can look at what you can do about it - either getting counselling or by getting practical help for an ongoing problem, such as money worries. Relieving stress - either by making changes in your life or by yoga, relaxation techniques or complementary therapy - can also make a big difference.

You should also take special care to look after yourself, which can be difficult when you are feeling depressed. Try and avoid drinking too much alcohol, eat healthily and get as much sleep as you can.

The tablet St John's Wort is available from your pharmacy and from many health food shops. While effective for mild depression and mostly safe on its own, St John's Wort interacts with many other medicines and can cause dangerous side effects. You should therefore not take it without medical advice if you are on any medication or have another medical condition.

WHERE CAN I GET HELP?

If you have moderate or severe clinical depression, you need to see your GP, who will probably want to prescribe you medicine.

Most antidepressants are safe and not addictive, and the modern ones have relatively few, mostly mild, side effects. These tablets do not cure your depression, but they should keep your symptoms under control. They may take some weeks to take effect, so if you think they are not working, it is well worth consulting your GP before stopping them.

How long your doctor will want you to stay on medication will depend on how severe your depression is, how quickly you improve and whether you have had it before. He will almost certainly recommend that you continue to take your medicine for several months.

If your depression is severe, your GP may refer you to a psychiatrist or a community psychiatric nurse (CPN). You can contact psychiatric staff directly at many hospitals through the Emergency Psychiatric Service. This service often allows you to go in and talk to someone without an appointment, although most operate limited opening hours. At other times you can ring your GP or go to your local Accident and Emergency department.

If you aren't sure whether you need a doctor straight away, you can ring NHS Direct on 0845 4647 outside normal surgery hours.

You may need counselling, which you can get privately - always go to a qualified therapist - or sometimes through your GP.