Agoraphobia

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 e.g. 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.

• Very common in primary care setting
• Tends to affect females more than males
• Commonest age of occurrence is 25- 35
• Prevalence rates of panic disorder have been quoted around the 1% level - suggesting it to be a chronic and common disorder which is probably underdiagnosed so that the prevalence is much higher.¹
• Agoraphobia affects up to one third of patients with panic disorders.¹

Panic attacks and agoraphobia are underdiagnosed and therefore a high index of suspicion is required.
Diagnosis requires the following:²

1. Avoidance of situations that provoke the anxiety (prominent feature). In the case of agoraphobia this involves not going out of the house and avoiding open spaces.
2. Symptoms (psychological and physical) arise mainly from anxiety and the anxiety is not secondary to other underlying psychiatric problems e.g. depression.
3. Anxiety manifests primarily in two or more of the following: crowds, public places, travelling alone or away from home.

This includes:³

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

Non-Drug

• Cognitive behavioural therapy - this involves exposure to the provoking situation and staying until anxiety passes. ⁴ This can be done through imagination or in vivo. However, this method can produce severe anxiety and can be very distressing for the patients and therefore needs to be performed in controlled situations. Never the less, cognitive behavioural therapy is superior to supportive psychotherapy alone. Some studies even suggest that CBT may be superior to TAD's.⁵
• Education - understand the problem
• Lifestyle changes - avoid alcohol and illicit drugs and stimulants⁶
• Self help groups - focus on relaxation and breathing exercises

Drugs

Benzodiazepines

Give short term relief and are not generally recommended as addictive and do not provide a long term solution. Patients who are already on long term benzodiazepines can be enrolled into CBT sessions and then an attempt made to gradually taper the dose of the benzodiazepine.⁷

Antidepressants

Tricyclic antidepressants can reduce panic severity and frequency of episodes. A meta-analysis found that antidepressants are just as effective as selective serotonin reuptake inhibitors (SSRI's).⁸ However, TAD's can be associated with side effects. Monoamine oxidase inhibitors have also been used and appear to produce good results but their side effect profile and associated dietary restrictions makes them unattractive.

SSRI's

These are first line. Paroxetine or fluoxetine have been used with good effects. Escitalopram is a highly selective serotonin reuptake inhibitor and appears as effective as other SSRI's in agoraphobia.⁹ Venlafaxine a serotonin-norepinephrine reuptake inhibitor is also as effective as SSRI's.¹⁰ The Committee on Safety of Medicines (CSM) advises that venlafaxine should be started and maintained under the supervision of a specialist due to concern regarding toxicity when taken in overdose.¹¹

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