This confusion is made all the worse because it is often difficult to tell the difference between feeling gloomy and having a depressive illness. Doctors make a diagnosis of depression after assessing the severity of the low mood, other associated symptoms and the duration of the problem.

Unfortunately, there is no brain scan or blood test that can be used to diagnose when a person has a depressive illness. The diagnosis can only be made from the symptoms.

Symptoms of depression

Stress can lead to you to feeling down and miserable. What is different about a depressive illness is that these feelings last for weeks or months, rather than days. In addition to feeling low most or all of the time, many other symptoms can occur in depressive illness (though not everybody has every one). These include:

• being unable to gain pleasure from activities that normally would be pleasurable.
• losing interest in normal activities, hobbies and everyday life.
• feeling tired all of the time and having no energy.
• difficulty sleeping or waking early in the morning (though some feel that they can't get out of bed and 'face the world').
• having a poor appetite, no interest in food and losing weight (though some people overeat and put on weight - 'comfort eating').
• losing interest in sex.
• finding it difficult to concentrate and think straight.
• feeling restless, tense and anxious.
• being irritable.
• losing self-confidence.
• avoiding other people.
• finding it harder than usual to make decisions.
• feeling useless and inadequate - 'a waste of space'.
• feeling guilty about who you are and what you have done.
• feeling hopeless - that nothing will make things better.
• Thinking about suicide - this is very common. If you feel this way, talk to somebody about it. If you think somebody else might be thinking this way, ask them about it - IT WILL NOT MAKE THEM MORE LIKELY TO COMMIT SUICIDE.

If you think you may have depression you should contact your doctor as soon as possible, no matter what test result you get.