Description

Literally, agoraphobia is a "fear of open spaces".

A clinical definition is "a fear of open spaces, especially those in which getaway may be difficult, which leads to avoidance of the situation". Being in the provoking situation usually leads to an anxiety attack.

There are three basic elements:

• Phobia.
• Avoidance of situations that might provoke the anxiety.
• Severe anxiety.

It can involve a number of phobias which may overlap, eg presence of crowds or travelling alone.

Once patients are in the provoking situation they develop sudden and severe anxiety - the anxiety is what they try to avoid.

Some patients can manage to continue their daily lives (with difficulty), whilst others are severely affected and may even become incapacitated.

Epidemiology

• Epidemiological data in the UK are hard to find. The Office for National Statistics published a survey in 2000 which found that one in six people living in private households had a neurotic disorder: 4% had generalised anxiety disorder and fewer than 2% had a related disorder such as a phobia.^[1] One American study found agoraphobia to be the least common of the anxiety disorders.^[2]
• It tends to affect females more than males.
• The most common age of occurrence is 25-35.
• Prevalence rates of panic disorder have been quoted around the 1-5% level - suggesting it to be a chronic and common disorder which is probably underdiagnosed so that the prevalence is much higher.^[3]
• Agoraphobia affects up to one third of patients with panic disorders and occurs before the onset of an attack.^[3]

Diagnosis

Panic attacks and agoraphobia are underdiagnosed and therefore a high index of suspicion is required.

Diagnosis requires the following:^[4]

Useful questions for a GP to ask the patient (or by proxy a carer) might thus be:

• What situations cause you anxiety or embarrassment?
• What symptoms do you get?
• Do you get the symptoms in places or situations from which escape might be difficult or embarrassing?
• Do you get the symptoms in situations in which help might not be available?
• Do you get the symptoms when travelling on public transport, standing on a bridge, being in a crowd or being in a queue? (NB: if symptoms develop in a limited number of situations - eg travelling in a car but not a train, using a lift, consider Specific Phobia; if symptoms are limited to social situations, consider Social Phobia.)
• Do you avoid certain situations (eg travel) because you feel panicky?
• Do you ever need the help of a companion in certain situations (eg travel)?
• What particularly worries you about the situation? (This may reveal another diagnosis - eg if the patient says that they fear contamination with dirt, this might indicate an underlying obsessive-compulsive disorder.)
• Have you had a traumatic event in the past (eg fear of travelling in a car after a car accident)? (Consider post-traumatic stress disorder.)
• Are you anxious about what is going on at home? Do you get panicky when you leave your family? (Consider separation anxiety disorder.)

Consider using a validated screening test such as the Beck's Anxiety Inventory, General Health Questionnaire, Hamilton Anxiety Scale (HAS) or the Hospital Anxiety and Depression Scale (HADS). The evidence base supporting the routine use of questionnaires in diagnosis and evaluation of treatment is limited but they are sometimes useful in assessing the severity and range of symptoms and to obtain a baseline against which future progress can be measured.^[5]

If the patient's agoraphobia is so severe that they are unable to attend for an assessment, the GP will need to consider a home visit.

Differential diagnosis

This includes:^[6]

• Social phobia.
• Generalised anxiety disorder.
• Depression, post-traumatic stress disorder.
• Physical disorders, eg ischaemic heart disease.

Management

The National Institute for Health and Clinical Excellence (NICE) recommends a stepped care approach.^[7]

Step 1: recognition and diagnosis

This has been dealt with in the introductory section and the 'Diagnosis' section, above.

Step 2: treatment by the GP

General

• Try to establish a rapport with the patient.
• Assure them that you will treat them in a non-judgemental manner and will respect their confidentiality and privacy.
• Explore their worries in order to get a perspective on how the condition is affecting their life.
• Assure them that decision-making is a shared process and try to achieve a joint agreement as to the best way to manage the problem.
• Provide information (verbal and written) in a way the patient and their family/carers can understand. This should include contact numbers and information about what to do and whom to contact in a crisis, as well as local and national self-help organisations and support groups, in particular where they can talk to others with similar experiences.
• Advise avoiding anxiety-producing substances, eg caffeine.
• It is important to exclude alcohol or drug misuse as a factor and to treat these problems if present. Reassessment after successful management of substance-related issues will reveal if this is true panic disorder. Response to pharmacological/psychological therapies is likely to be poor in the face of alcohol/drug misuse or dependence.

Offer the following interventions (listed as per NICE in the order - according to the evidence base - of duration of efficacy):

• Refer for cognitive behavioural therapy (CBT).
• Education - help the patient to understand the problem.
• Lifestyle changes - avoid alcohol and illicit drugs and stimulants.
• Self-help groups - focus on relaxation and breathing exercises.

Drugs

• Selective serotonin reuptake inhibitors (SSRIs) are first-line. Sertraline is the most cost-effective of the group. It is unlicensed for this use at the time of writing, so informed consent should be obtained and recorded in the notes before being prescribed by GPs.
• Tricyclic antidepressants - these can be as effective as SSRIs but are likely to cause more side-effects.
• Benzodiazepines do not provide a long-term solution but may be offered in the short term during a crisis. Follow the guidance in the BNF.

Self-help

• Give the patient details of books based on CBT principles and contact details of any available support groups. With the patient's permission, give relatives or carers details of support groups which can be useful in bolstering the patient's support network as well as patients themselves.
• Promote exercise as part of good general health.
• Monitor the patient on a regular basis, usually every 4-8 weeks, preferably using a self-completed questionnaire.

Step 3

Reassess the condition and consider another intervention.

Step 4

If two interventions have been offered without benefit, consider referral to specialist mental health services. Specialist treatment may include management of comorbid conditions, structured problem solving, other types of medication and treatment at tertiary centres.

Management may sometimes be complicated by the fact that the patient's condition prevents them from leaving the house to access treatment. If options cannot be selected which can be pursued at home (eg self-help treatment), discuss the patient with mental health services. There may be local options (eg domiciliary therapy by a community psychiatric nurse) which may be available.

For more details on management, see our separate article Panic Disorder.

Prognosis

Some patients may improve; however relapses are common. 1 in 3 patients has underlying depression and 1 in 5 will attempt suicide.