A phobia is an anxiety disorder in which you feel intense fear of a particular object or situation, but know all the time that there is no real danger. The fear over which you have no control occurs whenever the object appears or the situation arises, but at other times there are no symptoms. When you are overcome by the phobia, the psychological and physical symptoms may be so severe and frightening that you develop a fear of your own fear of the anxiety. There is a vast number of phobias; some of these are listed in Table 3. Simple phobias are those which are confined to a single class of object or situation and don't give much trouble between attacks. Most simple phobias are concerned with illness, injury and animals. Such phobias are common and probably normal in children but usually fade by early adolescence; just a few continue into adulthood. Adult phobias usually date from early childhood (average age 5 years) and continue for many years. A smaller number of simple phobias start in adult life after a very stressful experience. For instance, someone may develop a horse phobia after being thrown from a bolting horse. These adult phobias are more likely to respond to treatment than the long-standing variety developed in childhood. Two or three people in 100 suffer from simple phobias, roughly twice as many women as men.

AGORAPHOBIA
Some phobias are of a more complex kind with a more generalised pattern of fear and often with other associated problems. People with agoraphobia (literally "Fear of the Marketplace") become anxious if they have to enter public places like shops, streets or public transport unaccompanied. The symptoms are much like those of generalised anxiety disorder but there may also be other unpleasant features, such as spontaneous panic attacks, depression, depersonalisation and claustrophobia (fear of enclosed spaces). Unlike simple phobias, the situations that provoke anxiety and avoidance may gradually extend until the sufferer is more or less imprisoned in his or her own home.

Symptoms, such as depression, obsessions, panic attacks and fears of fainting and loss of control are all common in agoraphobia. This phobia usually begins in the 20s and 30s, later than simple phobias, which are usually 'left over' from childhood, or social phobia (see below), which often starts in late adolescence. Agoraphobia is twice as common in women than men (although that may be because fewer male sufferers seek help) and affects perhaps 5 people in 100.

The onset of the disorder often occurs when a person (usually a woman) is in a store or waiting for public transport. She becomes very anxious and feels faint, with her heart pounding. She goes home or is rushed to hospital and soon recovers. Next time she is in the same or a similar place, she may have another attack. The frequency of the attacks gradually increases and the range of situations in which they occur grows. If the phobia lasts for a year, it is likely to continue for several years.

Treatment consists of drugs and therapy. Behaviour therapy, in which sufferers are exposed to the situations which bring on their phobia, combined with anxiety management, can be effective in softening the fear. The therapist gradually introduces the sufferer to the object of the fear. In these cases, drugs are seen as a secondary treatment. Anxiolytic or antidepressant drugs may be used, especially the latter if the patient is also suffering from depression.

SOCIAL PHOBIA
A person who becomes inappropriately anxious when required to appear at some social function may be suffering from social phobia. The phobia may occur at social gatherings, in restaurants, at conferences or board meetings, especially if the person has to speak in public or do anything which makes them think that they will be observed or criticised. The symptoms are similar to those of other anxiety disorders, but most commonly include blushing and trembling.

Social phobia was known in classical times. The Greek philosopher, Hippocrates, suffered from it. Robert Burton, in his "Anatomy of Melancholy" (1621) describes Hippocrates' symptoms: "He does not come in company for fear he should be misused, disgraced, overshock himself in gesture or speech, or be sick; he thinks every man observes him."

Social phobia is more or less equally common in men and women and may affect I or 2 people in I 00. It often starts in the late 'teens and 20s, usually in some public place and for no obvious reason. It then returns in similar circumstances, becoming gradually more severe. The sufferer takes increasingly strong action to avoid the situation he or she knows will trigger it and may turn to alcohol to "steady the nerves". As with all the anxiety disorders, people with social phobia know that there is no real reason for their fears. The usual treatment for social phobia is cognitive behaviour therapy, in which you are exposed to the circumstances which lead to the phobia and learn how to manage your anxiety. Moclobemide (Manerix), a relatively new antidepressant, is also effective.