Emma Hall was 22 and in her second year at university when her panic attacks started. She worked hard and loved student life. However, the pressure of A-levels had coincided with the death of a friend. Initially, Emma did not connect this stressful period with the panic symptoms that appeared two years later.

James Clark, a 26-year-old investment banker, went straight to A&E after a panic attack in a restaurant. Despite several tests which gave him a clean bill of health, he was convinced that he was ill with a serious swallowing disorder. He became increasingly anxious and avoided restaurants, supermarkets and pubs, which he felt might trigger an attack. Eventually, he became confused, depressed and suicidal.

The disorienting symptoms of severe panic disorder can be completely disabling, says Annette. "You try hard to continue working, but life becomes a huge struggle."

A panic attack is an exaggeration of the body's usual response to stress, excitement or fear, says Dr Paul McLaren, medical director of the Priory Ticehurst Hospital in Kent. "The fear response gets switched on when there is no external danger and the body is flooded with a surge of adrenaline - the `flight or fight' hormone. The heartbeat speeds up and blood pressure rises; the sufferer breathes more rapidly and muscle tension increases."

For most people, the adrenaline is assimilated and the symptoms fade, but those who suffer frequent panic attacks appear to be acutely aware of how their bodies are reacting, and their perception of danger becomes internalised. They fear they are physically or mentally ill, or about to have another attack and, being sensitive to anything that reminds them of the first attack, they avoid certain situations for fear of another attack.

Most people know someone who has suffered from panic attacks. "My friends talk about them and I know a surprising number of people who have had them," says one 25-year-old market analyst. "A school friend had them when she was a teenager. She grew out of them but, at the time, it was serious. She would be rushed home from school several times a month." Another friend, she says, had three or four attacks while at university and yet another suffered them intermittently after her degree.

Panic attacks can happen at any age, but most sufferers experience a first attack when they are relatively young. Actress Nicole Kidman, 35, attracted attention and sympathy when, during her break-up with Tom Cruise, she described how she would sometimes feel panicky before the cameras. A year ago, at the Cannes Film Festival, it was reported that she was so overcome, she had to retreat into a cinema, holding on to her sister for support.

Specialists believe that about one in 10 people experience at least one attack, and perhaps three or four, during their lifetime. Some attacks last for only a minute or so; others may go on for 20 minutes. Those who suffer severely may have at least four attacks a month.

Panic attacks are not a modern phenomenon, but our perception of them has changed. A century ago, they might have been called the "vapours" - nervousness or an irritable heart. Later, such phrases as "anxiety neurosis" became fashionable. Not until the mid- Eighties was "panic disorder" defined as an illness in its own right. While separate from other anxiety disorders, panic attacks can also occur with, for example, phobias.

But why are some people more susceptible than others? Genes play a part, says Professor Roger Baker, a specialist in panic disorder and a consultant clinical psychologist at Dorset Healthcare NHS Trust. "If you have a history of panic disorder in your family, you are more likely to have an attack."

Recent evidence of a link between anxiety and a variation in a gene which helps to regulate levels of serotonin emerged from research at Ohio State University. Low levels of serotonin are linked with a number of psychological problems. However, it is unlikely that one or even several genes are responsible on their own, says Prof Baker. "Panic attacks are more likely to be triggered by a mix of psychological, genetic and environmental factors."

In his research, Prof Baker is considering how people "process or label" their emotions following stressful events such as job loss, bereavement or the build-up to exams. "We have found that those who see emotions negatively and try to control or even suppress them are more likely to have panic attacks much later." He is also working to provide a guide to the most effective therapies. Patients are being tested to assess how aware they are of their emotions, how well they understand what they mean, and if these emotions link them to an event that might cause them to become anxious.

Margaret Hawkins of No Panic, a national self-help charity, welcomes the recognition that panic attacks have received in recent years, but argues that, for many, help is given too late. "Patients often have to wait more than a year for cognitive behavioural therapy or other talking treatments. Drugs are not enough on their own."

Take control and conquer your fears

Self help

Take control. Keep a diary of your emotional reactions and analyse the event or thoughts that precede attacks.

Recognise possible triggers. These include erratic blood sugar levels, extreme dieting, withdrawal from sedating drugs such as tranquillisers, alcohol or nicotine.

Avoid overbreathing or hyperventilation, a common reaction under stress. By breathing rapidly you are trying to meet the demand for more oxygen from muscles, but you may also alter the blood's acid balance by breathing out more carbon dioxide. Low blood levels of the latter can trigger panic symptoms. Try breathing calmly and slowly into a paper bag, so that you breathe in a mix of oxygen and carbon dioxide.

"Tell yourself that this is a panic attack: it will not do anything to me and I should not do anything to maintain it," says Dr McLaren.

Drugs

Betablockers are calming and can prevent escalation, says Dr Peter Anderson at University College London's student surgery. "We combine their use with a thorough discussion of what might trigger the attacks and how to counter them."

Tranquillisers, taken for no more than two or three weeks, can help those who are so severely affected that they cannot think rationally.

Talking therapies

Psychotherapy helps those with established panic disorder to understand painful emotional conflicts and how they may be focusing on physical sensations to avoid them.

Cognitive behavioural therapy (CBT) is combined initially with drug therapy, and is the "gold standard" treatment, says Dr McLaren. "The key is to change habitual thoughts that reinforce the brain's panic response," he says. "I have seen high-powered executives make any excuse to avoid a meeting because of the fear of breaking down with panic. The aim is to retrain the brain by gradual exposure to anxieties."

The holistic approach

Clnical psychologists and psychiatrists recommend a wide range of complementary and alternative therapies. Annette Shaw, now 45 and a holistic health writer, says they were her salvation. Her attacks started, she thinks, as a response to her unhappiness with her first job. "They were severe and frequent, but compounded for many years by tranquillisers. I paid for psychoanalytic therapy, which convinced me that I was a capable person. As my confidence grew, I worked out my own approach to CBT. I also had aromatherapy sessions once a week for a year, took the Bach flower essence rescue remedies and worked hard at the holistic approach." She has not had a panic attack for two years.

Overcoming Panic by Derrick Silove and Vijaya Manicavasagar (Constable

What happens during an attack?

The symptoms appear suddenly and may include at least four of the following Shortness of breath, very rapid breathing, or a feeling of being smothered

Feeling faint, dizzy or unsteady

Very rapid heartbeat and palpitation

Trembling or shaking

Pains or discomfort in the chest

Sweating

Feeling of choking

Ringing in the ears

Numbness or tingling sensations

Flushing or chills

Nausea, stomach ache or diarrhoea

Feeling detached from one's

surroundings

Fear of losing control and of