Panic Disorder

Synonym: Panic attacks (recurrent)

Panic disorder can be a severe and disabling illness and is common in primary-care. It can be difficult to assess when it presents acutely, as many symptoms may also be experienced with physical illness. Sufferers often present repeatedly to their GP or local emergency department with worrying episodes of multiple symptoms that the patient may ascribe to life-threatening illness.

This condition often co-exists with agoraphobia - the avoidance of exposed situations for fear of panic or inability to escape. Agoraphobia is not a stand-alone diagnosis and occurs very rarely without panic disorder. Panic disorder is often classified into panic disorder, with, or without agoraphobia. Social phobia also often co-exists and is diagnosed where the situations avoided are predominantly social and interactive in nature.

There are many aetiological theories, none of which are proven in isolation. Several aetiological factors may contribute to its occurrence in a given individual. The postsynaptic serotonergic/adrenergic hypersensitivity hypotheses are probably the most biologically plausible and relevant to treatment response, but there are a host of others with their own proponents.

A common problem. A UK-based community survey of panic attacks found a lifetime prevalence of 8.6%.¹ In the US, lifetime prevalence is estimated at 3–5.6% for panic attacks and 1.5–5% for panic disorder.² A recent large-scale US epidemiological survey found lifetime prevalence rates of 5.1% for panic disorder, with lifetime prevalence of 4% for panic disorder without agoraphobia and 1.1% for panic disorder with agoraphobia.³ Psychiatric case-finding studies of patients presenting to emergency departments with chest pain found that up to 25% satisfied criteria for panic disorder.⁴

Symptoms

The patient will describe a history of sudden onset of episodes of panic featuring 4 or more of the characteristic symptoms listed above. The symptoms will reach their peak of intensity within ten minutes. Attacks usually last for 20–30 minutes and rarely persist beyond 1 hour. There is marked individual variation in the length of attacks. To be classified as panic disorder, the attacks should cause subsequent anxiety about their recurring or their effects, or bring about significant behavioural change in the patient. It is worth asking about any triggering caused by alcohol or drugs (including legal drugs such as caffeine, nicotine, complementary remedies or OTC preparations). Enquiry about other triggers for the attacks helps in constructing the differential diagnosis:

• Those that arise unexpectedly and without any obvious triggering situation or event are characteristic of panic disorder without agoraphobia.
• Those that arise in a predictable way as a follow-on to a given anxiety-provoking situation or event usually reflect a specific phobia-type diagnosis, or panic disorder with social phobia if the precipitant is a social phenomenon.
• Those that arise in an inconsistent or unpredictable way following exposure to a given anxiety-provoking situation or event suggest panic disorder with agoraphobia.

Signs

There are no specific physical signs associated with the condition, unless the patient is seen during a panic attack, when increased sympathetic outflow may manifest as tachycardia, hypertension, tremors, sweating etc. During the panic attack the patient may be extremely preoccupied about suffering death or a severe, life-threatening physical illness. The Mental Status Examination reveals no specific findings other than a reflection of anxiety and/or urgency in their appearance, speech or mood (this is not necessary to make the diagnosis). The patient's affect should be congruent with their mental state. Thought processes should be normal and thought content should be essentially normal, but may be preoccupied with death or illness. Thought content should be assessed for suicidal or homicidal ideation, or thoughts of self-harm. Judgement and insight are normally preserved. Abnormalities in thought processes or content (other than impulsive thoughts of suicide or self-harm) suggest alternative psychiatric diagnoses. The presence of incongruent affect should raise concerns that panic disorder is the wrong diagnosis.

Psychiatric disorders

Panic disorder is frequently associated with agoraphobia (affecting about 26% of sufferers) and/or social phobia (affecting about 33% of sufferers). There is a significant association with mood disorders, particularly depression, with lifetime prevalence rates as high as 50-60%. There appears to be a higher risk of suicide attempts than in the general population. Alcohol/substance misuse can complicate the picture, although the overall prevalence of alcohol and drug misuse is not thought to be higher than in the general population.⁴

Medical conditions

May co-exist, although strictly speaking this cannot then be termed panic disorder, if the symptoms arise directly from the physical illness. Cardiovascular disease such as mitral valve prolapse, cardiomyopathy and hypertension are associated. Chronic Obstructive Airways Disease and migraine headaches are also present in a larger proportion of sufferers than chance would suggest, as are functional disorders such as irritable bowel syndrome and tension type headache.

In acute presentation, it is important to exclude physical illness as a cause for the symptoms. In those who present recurrently in such a fashion, it is tempting to dismiss physical causes, but it must be remembered that concurrent physical illness is not impossible and basic assessment and tests should be carried out to exclude serious organic disease. It is best to avoid admitting patients to medical or surgical beds, unless there is a sound clinical reason to do so. The conditions listed below may present in a similar fashion to panic disorder.

Psychiatric conditions

• Agoraphobia (often co-exists)
• Social phobia (often co-exists)
• Anxiety disorders, including generalised anxiety disorder (may co-exist)
• Adjustment disorders
• Bipolar affective disorder
• Depression
• Dissociative disorders
• Factitious illness
• Somatisation syndrome
• Mental symptoms arising as a result of physical illness
• Obsessive-compulsive disorder
• Specific phobic disorders
• Post-traumatic stress disorder
• Social phobia
• Stimulant-drug misuse (including caffeine-related illness).

Physical conditions

• Hyperthyroidism
• Phaeochromocytoma
• Carcinoid syndrome
• Hypoglycaemic episodes (possibly due to insulinoma in those not using insulin/oral hypoglycaemic agents)
• Paroxysmal cardiac dysrhythmia
• Mitral valve prolapse
• Myocardial infarction
• Recurrent small pulmonary emboli
• Epileptiform disorders, particularly temporal lobe epilepsy
• Withdrawal from alcohol/sedatives/opiates
• Paroxysmal vestibular disorders, eg Ménière's disease.

There are no specific investigations to diagnose the condition, but clinicians may feel inclined to refer the patient, or carry out tests to exclude underlying physical causes for the symptoms. Whilst it is important not to miss likely physical causes, one should not endlessly or excessively investigate these patients. Such a course of action can leave them with the impression that there actually is a physical problem, which their doctor(s) just can't find. After initial exclusion of top-ranking physical causes, with the confirmation of characteristic clinical features of panic disorder, the absence of a physical cause should be clearly explained to the patient. Response to treatment will be better in those patients who accept the absence of physical causes for their symptoms, and in those who have an understanding of the nature of panic disorder as a primarily mental phenomenon.

General

There are many therapeutic options available, and the actual therapy given in the individual case should be discussed and chosen by patient and doctor. It is important to exclude alcohol or drug misuse as a factor and 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.

A significant proportion of patients with panic disorder will undergo spontaneous remission of their illness. However, the time this takes is highly variable and it appears difficult to predict which patients will improve without therapy.⁵ For this reason patients who present with panic disorder should be offered some form of therapy.

Short term use of benzodiazepines has been advocated in the past. However NICE guidance is that they should be avoided as they are associated with poorer outcomes in the long-term due to the risk of dependence.⁶ NICE advise that community-based therapy for panic disorder is appropriate for the vast majority of sufferers.⁶

Antidepressants

Antidepressant drugs have been shown to be effective in reducing the amplitude of panic, reducing frequency of or eliminating panic attacks, and improving quality-of-life measures in this group of patients.

• Meta-analyses seem to show no difference in efficacy between SSRIs and tricyclics, however the SSRIs seem to be better tolerated with lower rates of drop-out due to side effects.^7,8 This, however may reflect publication bias (studies showing no difference between drug classes are more likely to go unpublished).
• About 60% of patients given antidepressants will be free of panic attacks after 12 weeks, compared to 40% in placebo-control groups.
• Many SSRIs are licensed for use in panic disorder. Some patients experience an initial exacerbation of symptoms after starting the drug, but this should settle. If this is a severe phenomenon, then benzodiazepines can be prescribed with care, for a short period ( <2-3 weeks) to help get over this phase.
• The actual drug chosen will depend very much on tolerability in the individual patient, and clinician preferences.
• NICE guidance advises that patients being treated with SSRIs for this condition are made aware that although these drugs are not addictive, there is a potential for unpleasant symptoms as part of a discontinuation syndrome on withdrawal, particularly if this is done abruptly.⁶
• Six months of antidepressant therapy appears to be a suitable duration of treatment.
• SSRIs should be discontinued gradually and patients should be reviewed (about once a month to monitor for relapse).

Cognitive behavioural therapy (CBT)

Psychological treatments have a useful role to play in the management of panic disorder. These include techniques that allow the recognition and control of cognitive triggers to panic, and behavioural approaches to ameliorate the effects of impending panic. There is support for use of CBT:

• Various meta-analyses have found CBT to be superior to emotionally supportive psychotherapy.
• Recovery rates in various studies are impressive (up to 70% panic free, compared to around 30% of control patients after 8 to 15 sessions). At 2 years follow-up, up to 50% of patients have remained panic free in some series. However, these trial data may not reflect the real-world success rates achievable with CBT ( patient-selection bias and the loss of difficult cases to follow up).
• NICE recommends the use of CBT as an equally useful alternative to antidepressants.⁶

Where CBT services are not available or a patient is unwilling to see a psychological therapist, the use of self-help media (e.g. books - so-called bibliotherapy, or computerised CBT packages) that address the panic issue using a CBT model, have been shown to be similarly effective.⁹

See internet section for details of available publications and those recently assessed by NICE. Between 4 and 12 sessions (usually around 6) are thought to be most effective, with follow up of patients after sessions have discontinued, to detect relapse.

CBT and antidepressants

It is unclear whether there are any real differences in outcome between patients who take antidepressants and those who use CBT. Combining the two therapies has been claimed to have superior results in some trials, but the overall trial data suggest that there is probably little to be gained in combining the two treatments for uncomplicated cases in primary care. The exception might be patients with significant long-standing co-existing depressive illness and panic disorder, or those who show little or no response to either treatment given in isolation.

Referral for specialist evaluation

Offer a referral to specialist mental health services if the patient has not responded to both pharmacological and psychological therapy.⁹

Overall prognosis for long-term recovery is good with use of pharmacological or psychological therapies. There is a significant long-term relapse rate, but patients do seem to respond to further courses of therapy following relapse.

Those that suffer can help themselves by recognising triggers to panic and ameliorating them through avoidance or CBT-based strategies. Patients who notice that caffeine or other substances potentiate or trigger their attacks should avoid these precipitants. Recovered sufferers should be made aware that the condition may relapse and that they should seek early help for further treatment if panic attacks return.