Anxiety Disorders

Definition/diagnostic criteria Anxiety disorders include disorders that share features of excessive fear and anxiety, and related behavioural disturbances.

Several conditions constitute anxiety disorders as a whole, with subdivisions described in international classifications of disease such as The WHO’s International Classification of Diseases 11th Revision (ICD-11) and the Diagnostic and Statistical Manual Of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). The key diagnoses are generalised anxiety disorder (GAD) and more specific anxiety disorders, including social anxiety disorder, panic disorder, agoraphobia and specific phobias. Other anxiety disorders include separation anxiety disorder and selective mutism but these are not typically the remit of primary care.

The two international classifications’ criteria for the key disorders include:

Generalised anxiety disorder (GAD):

• Excessive anxiety and worry, occurring more days than not, with either general apprehension (‘free floating anxiety’) or excessive worry about multiple everyday events.
• The anxiety/worry are associated with physical symptoms of autonomic arousal.
• The individual finds it difficult to control the worry.

Social anxiety disorder (SAD):

• Marked fear or anxiety about one or more social situations in which the individual is exposed to possible scrutiny by others (e.g. social situations, being watched).
• The individual fears that they will act in a way or show anxiety symptoms that will be negatively evaluated by others.
• The social situations almost always evoke fear or anxiety, are disproportionate to actual threat, and are avoided or else endured with intense fear or anxiety.

Panic disorder:

• Recurrent unexpected panic attacks, unrelated to particular stimuli or situations.
• Persistent concern about panic attacks, their consequences, or behaviours to avoid their recurrence.
• Impairment in important areas of functioning.
• The disturbance is not attributable to substances, another medical condition or other mental disorder.

Agoraphobia:

• Marked fear or anxiety in, or in anticipation of, situations which may be difficult to escape from or where help may not be available in the event of developing panic attacks or other embarrassing symptoms.
• The situations are actively avoided, entered under specific conditions (e.g. with someone) or else are endured with intense fear or anxiety.

Specific phobia criteria:

• Marked and excessive fear or anxiety that consistently occurs upon exposure or anticipation of exposure to one or more specific objects or situations that is out of proportion to actual danger.
• The phobic objects or situations are avoided or else endured with intense fear or anxiety.

Epidemiology Anxiety disorders are the most common mental disorders, affecting 301 million people worldwide in 2019. Onset is typically in childhood or adolescence, and more females than males are affected.

UK prevalence data is scant in terms of subdivisions of anxiety disorders, but specific phobias, social anxiety disorder and GAD are the most common. Regarding specific phobias, the top three in the UK are heights, spiders and public speaking. Specific phobias account for the majority of anxiety disorders, with a prevalence around 3.5-7% in Europe.

GAD occurs in 4-7.9% of patients in primary care settings, but is underdiagnosed and only a third of people with the condition receives adequate treatment. GAD is the most common anxiety disorder in old age, but most patients are in the 35-55 years age bracket. The median prevalence of SAD in Europe is 2.3%; for context this is more common than the major autoimmune conditions.

Panic attacks can exist without a diagnosis of panic disorder, with the latter having a 12-month prevalence of up to 2% in Europe.

Agoraphobia is the least prevalent of the anxiety disorders discussed here.

Diagnosis
Clinical features: Specific criteria need to be met, based on the ICD-11 and DSM-5-TR, in order to make the diagnosis. For each definition, it is a prerequisite that the presentation is not attributable to substances, another medical condition or another mental disorder, so the possibility of these must be considered in order to make the diagnosis. Ensure a drug history is taken – anxiety can be an adverse effect of some medication such as salbutamol, theophylline, beta-blockers, herbal medicines (including ma huang, St John’s wort, ginseng, guarana, belladonna), corticosteroids and some antidepressants.

Diagnosis can be made by eliciting the symptoms (e.g., thoughts, physical symptoms) and situations (e.g., being out alone, being exposed to stimuli) that are explicitly mentioned in the DSM or ICD criteria. Anxiety and fear are slightly different entities; fear is the emotional response to real or perceived imminent threat, whereas anxiety is anticipation of future threat. A history will involve the nature of the physical and mental symptoms, as well as precipitating and perpetuating factors. Symptoms must be persistent over at least several months and cause distress or impairment in important areas of functioning (e.g., social, occupational).

Physical symptoms attributable to anxiety may include muscle tension or motor restlessness; sympathetic autonomic overactivity as evidenced by frequent gastrointestinal symptoms such as nausea and/or abdominal distress, heart palpitations, sweating, trembling, shaking, and/or dry mouth; subjective experience of nervousness, restlessness, or being ‘on edge’; difficulty concentrating, irritability and sleep disturbances.

In panic disorder, physical symptoms are more discrete episodes of intense fear/apprehension rapid and concurrent onset of several characteristic symptoms. Panic attacks are manifest by an intense and severe surge of fear, with four or more of the following symptoms: palpitations, sweating, trembling/shaking, sensations of shortness of breath/smothering, feelings of choking, chest discomfort, nausea/abdominal symptoms, dizziness/faintness/light-headedness, chills/hot flushes, fear of imminent death. Symptoms typically peak after about 10 minutes and resolve by 30-45 minutes.

Investigations: Disorder-specific rating scales are available and can be used to characterise the severity of specific phobia, social anxiety disorder, panic disorder, agoraphobia and generalised anxiety disorder. A commonly used scale in primary care is the Generalised Anxiety Disorder questionnaire (GAD-7). Scores of 5, 10, and 15 are taken as cut-off points for mild, moderate, and severe anxiety respectively.

Clinical investigations are not indicated for a diagnosis of an anxiety disorder, other than for the purpose of ruling out a physical health condition, if appropriate. Depending on the presentation, cardiovascular assessment and endocrinological measurements may be indicated (for example, thyroid function testing, free catecholamines).

Treatment Treatment should involve addressing any potential underlying or concurrent physical or mental health conditions. This is particularly true of depression, where treatment may resolve the concurrent anxiety symptoms.

The first step in treatment – regardless of the severity or type of anxiety – is to provide the patient with information. This may be verbal, written, online, or a combination. NICE have produced patient information leaflets on generalised anxiety disorder and panic disorder which are helpful. Communicating the diagnosis helps the person contextualise and begin to understand their experience.

Treatment options depend on the severity of the symptoms, associated risks and patient preference, and vary slightly depending on the particular anxiety type, but a general summary is below.

Active monitoring
Initially, active monitoring alongside the provision of information, may be an adequate first step. Scheduled review is needed to clinically assess symptoms and functioning.

Self-care information about sleep hygiene, alcohol and caffeine intake, and the benefits of regular exercise should be given.

Psychological interventions
If symptoms have not improved, and there is not significant functional impairment, low-intensity psychological interventions are recommended. The availability and access depend on local arrangements, but treatment methodologies include individual non-facilitated self-help, individual guided self-help, or psychoeducational groups. Patients who are not improving despite low-intensity treatments, or who have marked functional impairment, then high-intensity psychological interventions such as CBT or applied relaxation are recommended, along with consideration of pharmacological treatment.

Psychological interventions are a clear first-line treatment for specific phobias and should be based on exposure techniques.

Pharmacological treatment
First-line drug treatment is a selective serotonin reuptake inhibitor (SSRI). However if a patient has previously been on an alternative medication with good effect, for example a serotonin-noradrenaline reuptake inhibitor (SNRI), then it would be reasonable to go to that medication choice first line. Treatment periods of up to 12 weeks may be needed to assess efficacy, but an absence of clinical benefit within four weeks warns that a response to unchanged treatment is unlikely.

Sertraline is recommended as the first-line SSRI, but an alternative SSRI can be used if sertraline is ineffective. Note that paroxetine is licensed for GAD and SAD, and escitalopram for GAD, SAD and panic disorder. Citalopram is only licensed for panic disorder, and fluoxetine does not have a licence for the indications here. NICE reflects this in its recommendations for paroxetine or escitalopram as second-choice alternatives. Instead of a different SSRI, an SNRI can be tried – venlafaxine (licensed for GAD, SAD, panic disorder) or duloxetine (GAD).

If the person cannot tolerate SSRIs or SNRIs then pregabalin can be considered, bearing in mind that it is a drug of potential abuse and dependence. If needed, the starting dose would be 150mg daily (in two to three divided doses). If required, it can be increased in steps of 150mg daily at 7-day intervals. Maximum dose 600mg daily in two to three divided doses.

When using medications, be aware that symptoms may transiently worsen, and insomnia can be a particular problem. Preparing the patient for this, and increasing active monitoring at this time, is good practice. The risk of increased suicidal behaviour with the use of antidepressant medications, and with pregabalin, is small but should still be highlighted to the patient, with appropriate safety-netting.

Quetiapine is the only antipsychotic with strong evidence of benefit in acute treatment and prevention of relapse in patients with generalised anxiety disorder. It may be used in patients who have had a non-response or intolerance to other medication, and is sometimes prescribed to augment antidepressants or used to facilitate sleep initially.

Benzodiazepines are effective in the treatment of anxiety disorders, but can cause sedation and cognitive impairment, even with short-term use. Tolerance and dependence can occur (especially in predisposed patients) with prolonged use, and it is hard to identify those patients at risk of developing long-term problems, so use should be limited to short term. To reduce the risk of dependence on benzodiazepines they should generally not be prescribed as a regularly administered medication for longer than four weeks. Ideally, they should be given on an ‘as required’ basis and intermittently every few days during this period.

For some patients, benzodiazepines such as diazepam can cause paradoxical agitation. Benzodiazepines are most useful acutely, for example when medication is being changed, during a crisis, or for a one-off specific indication (for example to address an acute anxiety episode, such as at a funeral). Patients should always be warned about drowsiness and impaired executive function, and not to drive or operate machinery. They should also not take a benzodiazepine if impaired functioning would present a risk to other people, for example in the context of fear of flying where rapid evacuation of an aircraft in an emergency could be hindered. If appropriate, short-term use of diazepam should start at 1-2mg up to 3 times a day. It should also be noted that diazepam has longer-lasting active metabolites, which can accumulate with repeated dosing, especially in elderly patients and those with physical health problems.

Prognosis Prognosis for anxiety disorders is complex because there are often comorbid anxiety disorders, as well as co-existing mood disorders or other psychiatric morbidity. Generalised anxiety disorder is often co-morbid with major depression, panic disorder, phobic disorders, health anxiety and obsessive-compulsive disorder. Around two-thirds of patients with panic disorder develop agoraphobia. Untreated, the course is typically waxing and waning – but this can happen even with treatment. It has been noticed that for primary care patient, the course of anxiety is often prolonged. Most people with GAD still experience symptoms after 10 years and half of those who remit will relapse.

Individuals with anxiety may be more likely to have suicidal thoughts, attempt suicide and die by suicide than those without anxiety. Panic disorder, generalised anxiety disorder and specific phobia have been identified as the anxiety disorders most strongly associated with a transition from suicidal thoughts to a suicide attempt.

Long-term treatment is likely to be needed.

Written by Dr Emma Nash, a GPSI in mental health in Hampshire