THE CENTRE FOR Suicide Research and Prevention reported last year that 9 per cent of Hong Kong people aged 15 to 59 had major depressive symptoms. This is equivalent to about 400,000 people. In the US, the annual cost of depression is estimated at US$44 billion - about the same as for coronary heart disease. According to the coroner's court, 1,238 people committed suicide in Hong Kong in 2003. Depression is a major risk factor for suicide. Unfortunately, there's a stigma attached to mental illness in Hong Kong, and many people are reluctant to learn more about it. As a result, many sufferers are unable to recognise warning signs and don't seek help. And there are many ways to get assistance. Cognitive therapy, for example, is regarded by many as one of the most successful forms of psychotherapy. It was developed by Aaron Beck, a practising psychiatrist frustrated by the lack of progress of his clients using more traditional forms of psychotherapy. Before its development, there were three ways to treat depression: traditional psychoanalysis, which developed from Freud's belief that depression is caused by unconscious hostility turned inward and focuses on the past; behavioural therapy, which makes use of reward and punishment in an attempt to alter behaviour; and drug therapy, which assumes that depression is the result of chemical imbalances in the brain and is best treated with drugs. Beck reasoned that since we can think our way into trouble, we could learn to think our way out. Cognitive (which means thinking) therapy is all about tuning in to your inner dialogue or that 'voice in your head' that impacts your emotions, behaviour, physical experiences and events. Proponents say cognitive therapy enables you to learn to rewrite the script and, therefore, make the right changes. This starts with identifying irrational thoughts and beliefs and recognising the ways these beliefs are damaging and self-reinforcing. The next step is to replace any maladaptive thought patterns with healthier ones. It's not the event itself that leads us to feel depressed, but the way we interpret the event. Cognitive therapy is about taking responsibility for your life. The biggest support for cognitive therapy came from a 1989 National Institute of Mental Health study in the US that tested the effectiveness of treating depression with drug therapy, interpersonal therapy and cognitive therapy. Cognitive therapy was found to work as well as the other two. That year, Beck was awarded the American Psychological Association's Distinguished Scientific Award for the Application of Psychology. A more recent study, published in The Archives of General Psychiatry in 2004, found that although cognitive therapy and medication are regarded as equally effective in treating depression, they work in different ways. In this study, 14 patients who attended 15 to 20 sessions of therapy were compared with 13 equally depressed patients treated with antidepressants. Brain scans before and after treatment showed that both treatments were equally effective. Cognitive therapy led to changes in the frontal cortex, the area of the brain dealing with higher reasoning. There were no such changes in the patients who took the antidepressants. Scans of the drug group showed changes in the brain stem and limbic system, which is involved in basic emotions and memory - areas where cognitive therapy appeared to have no effect. According to the study's senior author, Helen Mayberg, these findings may help explain why a combination of the two approaches is often best. When someone is depressed, they experience a change in their behaviour, feelings and thinking. They may lose interest in their usual activities and feel they have no energy. They may experience changes in their sleeping and eating habits. They may have a diminished ability to think or concentrate and have difficulty making decisions. Although the most obvious sign of depression is being sad, depressed people also see themselves in a negative way. They may feel guilty, worthless and pessimistic about themselves, the future and the world at large. Numerous studies of the thoughts of depressed individuals have found that they have continuous unpleasant thoughts. A vicious cycle ensues, whereby negative thoughts result in withdrawal from activities that would make people feel better - which, in turn, leads to further negative thoughts about being lazy, useless or hopeless. When someone is depressed, many of their bad feelings are based on errors in thinking, or what cognitive therapists call cognitive distortions. These relate to the way individuals see themselves and interpret things that happen to them. Although we all occasionally misinterpret cues from the environment, when people are depressed they make thinking errors more frequently - and they're almost always negative. Such negative thoughts tend to be automatic and not based on logic. Typically, the depressed person focuses only on negative events and disregards positive ones. Everyday annoyances become exaggerated, and one's ability to cope is underestimated. One of the techniques used in cognitive therapy is to keep a so-called thought-catching record to learn to recognise those automatic or hot thoughts that lead you to feel bad. We're often unaware of the habitual nature of our thinking processes. Thoughts can become like a well-worn script that shapes our self-image, often in a negative way. We may have a tendency, for example, to see ourselves in black-and-white terms (so-called 'all or nothing' thinking) - if a presentation, say, wasn't flawless, we label ourselves a total failure and feel depressed. Or we may have a tendency to reach negative conclusions without the facts to support them - for example, assuming someone doesn't like you because they didn't acknowledge you when you passed them. The purpose of keeping records is to help identify distortions in thinking so sufferers can come up with alternative, more rational explanations. Cognitive therapy techniques have also been adapted for treating anxiety, dysfunctional relationships, substance abuse and eating disorders. Unlike many other psychological therapies, cognitive therapy is relatively shorter - usually somewhere between five and 20 sessions. 'It's important for the public to understand that it's not a stigma to seek help,' says a Centre for Suicide Research and Prevention spokesman. 'We want to let people know that if someone gets depressed, they need to see a doctor.'