Anxiety is the most common of all the mental health disorders. Excessive, irrational fear and dread can severely restrict everyday life. The pharmaceutical industry is exploring how the brain works when affected by anxiety; from this will spring further innovative therapies.

What is anxiety? Top

Anxiety is the most common of all the mental health disorders. The prominent forms are generalised anxiety disorder, panic disorder, social anxiety disorder, and obsessive compulsive disorder. Each form has its own distinct features, but they are all bound together by a common theme of excessive, irrational fear and dread.

Generalised anxiety disorder is characterized by chronic and exaggerated worry and tension, even though nothing seems to provoke it. It is diagnosed when someone spends at least six months worried excessively about a number of everyday problems, such as excessive worries about health, money, family, or work. In general, people realise that their anxiety is more intense than the situation warrants. Usually the impairment is mild and people with the disorder neither feel too restricted in social settings, nor do they characteristically avoid certain situations. However, severe forms can be extremely debilitating, making it difficult to carry out even ordinary daily activities.

People with panic disorder have feelings of terror that strike suddenly and repeatedlywith no warning. When a panic attack strikes, people report heart pounding, increased body sweat, weakness, fainting, or dizziness. While most attacks average a couple of minutes, occasionally they can last up to a quarter of an hour. Some people avoid everyday activities such as shopping and driving; basically, they develop a fear of open spaces and avoid any situation that would make them feel helpless in case of another panic attack. When life becomes so restricted, as happens in about 30 per cent of people with panic disorder, the condition is called “agoraphobia”, from the Greek words “agora”, which was the name of the great market place in the centre of ancient Athens, and “phobia” for fear.

Social anxiety disorder (or social phobia) involves marked, persistent and unreasonable fear of being observed or evaluated negatively by others in social performance or interaction situations. The disorder is associated with significant suffering and increased suicidal thoughts. Up to 80 per cent of patients have forms of mental illness, mostly major depressive disorder, personality disorders and substance abuse. Until recently the symptoms of social anxiety disorder were overlooked or dismissed as normal personality traits equivalent to shyness.

People with obsessive-compulsive disorder are plagued by persistent, unwelcome thoughts, or by the urgent need to engage in certain rituals. They may be obsessed with germs or dirt and wash their hands over and over, or they may be filled with doubt and feel the need to check things repeatedly. The disturbing thoughts are called obsessions, and the rituals that are performed to try to get rid of them are called compulsions. Most adults with the condition recognise the senselessness of their behaviour, but they cannot stop it. The course of the disease is variable; symptoms may ease over time, or they can grow progressively worse.

Who does anxiety affect? Top

The close correlation between depression and anxiety is one of the reasons for the large variations in the results of epidemiological anxiety studies. The number of patients who only suffer from anxiety was estimated at 30 million people in five major European markets in 2002. The lifetime risk of experiencing an anxiety disorder is approximately 20 per cent for men and approximately 30 per cent for women.

Generalised anxiety disorder comes on gradually and most often hits people in childhood or adolescence, but can begin in adulthood too. It is more common in women than in men and affects around three million people in Europe. Panic disorder affects some four million Europeans, and is twice as common in women as in men. It can appear at any age, but most often begins in young adults. Not everyone who experiences panic attacks will finally develop panic disorder. Social anxiety disorder affects about five million adult Europeans. Women and men are equally affected. The disorder usually begins in childhood or early adolescence, and there is some evidence that genetic factors are involved. The disorder often occurs alongside other forms of anxiety or depression. Obsessive-compulsive disorder afflicts about three million adults in Europe. It affects men and women in approximately equal numbers and usually first appears in childhood, adolescence, or early adulthood.                                                          Simplified cross section of the human brain

Present treatments Top

Most people with anxiety disorders usually respond well to medications or carefully targeted psychotherapy. The choice of one or the other, or both, depends on the patient’s and the doctor’s preference, and also on the particular anxiety disorder. In each case, early treatment of anxiety disorders holds theoretical promise in the reduction of long-term morbidity. The major classes of medications used for the treatment of various anxiety disorders are antidepressants, tranquillisers and beta-blockers.

The class of antidepressant medicines can roughly be clustered into the newer groups of azipirones, azaspirones and selective serotonin reuptake inhibitors (SSRIs), the well-established tricyclic compounds and the older monoamine oxidase inhibitors (MAOIs). With all medications, it will take several weeks before symptoms start to fade.

Azipirones and azaspirones, which act as 5HT1 (serotonin) agonists, are used to treat general anxiety disorder. SSRIs are commonly prescribed for panic disorder, social anxiety disorder and obsessive-compulsive disorder. Tricyclics are useful in treating people with anxiety disorders and depression. Similarly, they are started at low doses and gradually increased. For anxiety disorders other than obsessive-compulsive disorder, they are as effective as the SSRIs. MAOIs are the oldest class of antidepressant medications. They are helpful for people with panic disorder and social anxiety disorder.

Tranquillisers of the benzodiazepine group relieve anxiety symptoms quickly and in general are well tolerated. Because people may develop a tolerance to them, tranquillisers are generally prescribed for short periods of time, with the exception of panic disorder, for which they may be used for six months to a year. Finally, beta-blockers, currently prescribed to treat heart conditions, have also been found to be helpful in social anxiety disorder, especially when a feared situation can be predicted in advance.

What’s in the development pipeline? Top

Other newer antidepressants are under study in clinical investigations of Phase 2 and 3 in anxiety disorders. Furthermore, several Phase 3 clinical studies are being conducted to find out whether a combination of medications can rapidly improve anxiety disorder symptoms.

The longer-term future Top

Pharmacological research is yielding improved therapies that can help most people with anxiety disorders lead productive, fulfilling lives. And basic research into the causes, diagnosis, prevention, and treatment of anxiety disorders is ongoing. To this end, scientists are harnessing the most sophisticated tools available to determine the causes of underlying brain disorders. These are complex and probably result from a combination of genetic, behavioural, and developmental factors.

Several parts of the brain are key contributors in a highly dynamic interplay that gives rise to the emotions of fear and anxiety. Much research concentrates on the amygdala, an almond-shaped structure deep within the brain, which is believed to serve as a communications hub between the parts of the brain that process incoming sensory signals and the parts that interpret them. Other research focuses on the hippocampus, another brain structure that is responsible for processing threatening or traumatic stimuli. The hippocampus plays a key role by helping to encode information into memories. Also, research has found that other parts of the brain called the basal ganglia and striatum are involved in obsessive-compulsive disorder.

By learning more about the brain circuitry involved in fear and anxiety, scientists may be able to devise new and more specific treatments. For example, it may be possible to increase the influence of the thinking parts of the brain on the amygdala, thus  placing the emotional response of fear and anxiety under conscious control.