INTRODUCTION

Anxiety is a universal and normal human experience. It has survival value when it leads an individual to avoid danger. Anxiety is an important component of the mammalian ‘fight or flight’ response and one manifestation of sympathetic nervous system arousal. A certain degree of anxiety is often associated with increased performance, but excessive anxiety is associated with reduced performance. Anxiety accompanies most general medical conditions such as heart attacks and strokes. It also accompanies most mental health problems such as depression, dementia and schizophrenia. However, anxiety can be the main feature of several anxiety disorders that are not necessarily associated with a general medical condition or another mental health problem. This chapter is about these so-called primary anxiety disorders. Key issues include the diverse presentation of anxiety disorders and the selection of appropriate treatment approaches for older people.

EPIDEMIOLOGY

Anxiety disorders are the commonest mental disorders in older people after dementia. The 1997 National Survey of Mental Health and Wellbeing (NSMHW) (Australian Bureau of Statistics 1998) found that 3.5% of males and 5.4% of females aged 65 years and over were suffering from an anxiety disorder. This survey was limited to community-residing individuals without significant cognitive impairment and thus was likely to have underestimated the true prevalence of anxiety disorders in older people. However, the survey found that the prevalence of anxiety disorders declined with age. Table 23.1 shows the prevalence of specific anxiety disorders among people aged 65 years and over from the same survey.

Table 23.1 Prevalence of anxiety disorders in older people

Source: Australian Bureau of Statistics (1998).

CLINICAL FEATURES

Generalised anxiety disorder (GAD) is characterised by longstanding pathological anxiety. As currently defined by DSM–IV (American Psychiatric Association 2000), this anxiety must persist for at least 6 months for the diagnosis to be made. The person with GAD commonly worries or ruminates about many different things and experiences these worries as uncontrollable. Older people seem particularly prone to worry about their health and finances, or about the circumstances of their children or grandchildren. The topics of worry are often in the indeterminate future and not under the control of the person. Sometimes, the person with GAD also has free-floating anxiety (i.e. anxiety without a clear subject or focus). They usually feel nervous and unable to relax. They often feel irritable and restless and report difficulty concentrating. They are hypervigilant and startle easily. They often report increased muscle tone or tension and associated aches and pains. Not infrequently they have a fine tremor and psychomotor agitation. They commonly report marked sleep disturbance, with initial, middle and terminal insomnia and unrefreshing sleep. They often feel fatigued.

Clearly, these symptoms overlap to a considerable degree with the symptoms of major depression and may occur in many other psychiatric disorders. GAD also needs to be distinguished from what might be termed normal worry and from a variety of other conditions. These include hyperthyroidism, excessive caffeine consumption, the use of stimulants such as pseudoephedrine and amphetamine, and alcohol or benzodiazepine withdrawal.

Panic attacks are discrete episodes of marked anxiety that typically last no more than 10 minutes. Classical panic attacks, as described in DSM–IV (American Psychiatric Association 2000), are much more commonly experienced by young and middle-aged people, but do occasionally occur in older people. The anxiety experienced in a panic attack reaches its peak intensity rapidly and physical symptoms such as shortness of breath, tachycardia, palpitations and a choking sensation occur commonly. Other likely symptoms include chest tightness, chest pain, sweating, tremor, paraesthesiae, nausea, and hot or cold flushes. The person typically catastrophises about their situation, fearing collapse, stroke or even death. This leads to frantic attempts to escape from the situation that is associated with the attack, such as a supermarket checkout queue or crowded shopping mall. Alternatively, the person is afraid that they will embarrass themselves in front of others or ‘go crazy’.

When panic attacks occur both unexpectedly and frequently, in the absence of phobic avoidance but in the presence of anticipatory anxiety, panic disorder is diagnosed. Anticipatory anxiety refers to a persistent fear of another panic attack or fear of the consequences of a panic attack. However, it is important to emphasise that panic disorder is uncommon in older people. When classical panic attacks do occur in older people, they are often secondary to another mental health problem such as depression, psychosis, delirium or dementia.

A more common type of panic in older people is the so-called ‘limited-symptom panic attack’. These episodes do not meet all the criteria for a full-blown panic attack, but nevertheless cause the older person considerable distress and may be associated with similar phobic avoidance.

‘Phobic avoidance’ is the term used to describe the avoidance of objects or situations that cause excessive or irrational fear. The feared objects or situations do not cause a realistic threat, although, like snakes and electrical storms, might have the potential to cause real problems in some circumstances. As already noted, such objects or situations may also be associated with panic attacks. Phobic avoidance may occur in otherwise normal older people, but when it causes marked distress, together with social or occupational dysfunction, it is likely to amount to a phobic disorder such as specific phobia (also known as simple phobia), social phobia (also known as social anxiety disorder) or agoraphobia (with or without a history of panic attacks).

Specific phobias involve the avoidance of objects (e.g. moths, spiders) or situations (e.g. flying, confined spaces). Most specific phobias come on in childhood or early adult life. Some resolve without treatment, but some persist into middle age or later life. Simple phobias are very prevalent and often do not cause significant distress or disability because the person successfully avoids the phobic stimulus (e.g. snakes, lifts). However, some cause great distress and/or disability and require treatment.

Social phobia involves the avoidance of social situations that cause marked anxiety. Such situations include public speaking, tests and examinations, eating and drinking in front of others, musical or other performances (‘stage fright’), and the use of public toilets (e.g. urinals) in the presence of others. Social phobia needs to be distinguished from normal shyness and other Axis I and Axis II psychiatric disorders.

Agoraphobia is literally ‘fear of the marketplace’ and most commonly occurs in people who experience frequent panic attacks in the context of panic disorder with agoraphobia. Agoraphobia without a history of panic attacks is much less common. According to DSM–IV (American Psychiatric Association 2000), agoraphobia involves fear and avoidance of situations from which escape might be difficult or embarrassing, or in which help might not be available if a panic attack should occur. Most people with agoraphobia have much less difficulty entering feared situations if someone else accompanies them. As a consequence, they may avoid travelling alone or staying home alone. People with agoraphobia avoid crowded situations and confined spaces because escape might be difficult. Such situations commonly include public transport, lifts, tunnels and bridges. They commonly avoid situations from which it might prove embarrassing to make a hasty escape. Such situations include supermarkets, queues, restaurants and shopping malls. As time goes on, the person with agoraphobia tends to extend the number of situations they avoid until they are quite limited in where they feel they can go safely. By the time they present for treatment, they have often had symptoms for 12 years or more.

Obsessive-compulsive disorder is characterised by obsessions and compulsions. Obsessions are uncontrollable ego-dystonic thoughts, images and impulses that cause marked distress or anxiety. By ‘ego-dystonic’ it is meant that the person has insight into the abnormal and often bizarre nature of their symptoms while experiencing them as products of their own mind. Compulsions are repetitive behaviours that can be observable (rituals) or unobservable (mental compulsions). Compulsions are repetitive attempts to ‘undo’ obsessions, reduce anxiety or prevent harm. However, they provide only temporary relief from the anxiety and distress associated with the obsession. Obsessions commonly involve neatness and symmetry, pathological doubt, contamination, and sexual and aggressive themes. For instance, some people will report obsessional images of knives dripping with blood and similarly dramatic themes. These images, which are experienced ‘in the mind’s eye’, need to be distinguished from visual illusions and hallucinations. Compulsions commonly involve checking, washing, cleaning, counting, confessing, hoarding or arranging objects in a certain pattern.

Post-traumatic stress disorder (PTSD) is a severe anxiety disorder which, according to DSM–IV (American Psychiatric Association 2000), occurs after exposure to an event in which the person experiences or witnesses actual or threatened death in themselves or others, and responds with intense fear, helplessness or horror. It occurs in about 20% of people exposed to such a traumatic event. The most characteristic symptom of PTSD is repeated intrusive reexperiencing of the traumatic event through flashbacks and dreams. This is usually associated with avoidance behaviour, hyperarousal and emotional numbness.

Avoidance behaviour involves avoiding reminders of the traumatic event, including the location of the event. Hyperarousal involves insomnia, hypervigilance, impaired concentration and a lowered startle threshold. For example, many people with PTSD startle dramatically when a car backfires. Emotional numbness may include losing interest in interpersonal relationships and a sense that they can no longer feel emotions normally. A variety of other symptoms may also occur in PTSD. These include dissociation, physical symptoms and irritability. People with PTSD may abuse alcohol, prescribed medication and illicit substances in an attempt to deal with their symptoms.

In older people, chronic PTSD has commonly resulted from wartime experiences, including combat for men and rape for women. Older refugees have often experienced torture and trauma in their countries of origin. PTSD may also arise following motor vehicle accidents and train crashes, as well as natural disasters such as earthquakes, floods and bushfires. Some victims of childhood physical and sexual abuse develop chronic PTSD symptoms. PTSD is another condition that can be challenging to treat. Although there once was a vogue for immediate ‘debriefing’ of victims of traumatic events, it is now clear that this may sometimes do more harm than good. Most people recover from the effects of psychologically traumatic events without specific intervention. However, some people develop chronic and disabling symptoms that require active management.

AETIOLOGY

People vary enormously in their propensity to experience anxiety. Research suggests that the personality trait of neuroticism is powerfully associated with the risk of anxiety symptoms and anxiety disorders at all ages. Neuroticism is the tendency to get upset and remain upset following adverse life events. So it should come as no surprise to learn that adverse life events, particularly those that involve threat or loss, are strongly associated with risk of clinically significant anxiety. Although much of the tendency towards high or low neuroticism is thought to be under genetic control, no single gene of large effect has yet been discovered. Environmental factors, including early life experiences, are thought to be important in shaping the type of anxiety problem that a vulnerable individual will develop.

Even in anxiety disorders with a clear environmental precipitant, such as PTSD, genetic factors are important. Anxiety may also be secondary to other mental health problems (e.g. depression or dementia), secondary to a general medical condition (e.g. hyperthyroidism or Parkinson’s disease), or secondary to drug (e.g. amphetamine) or alcohol use. Certain parts of the limbic system of the brain seem to be important for the experience of panic and anxiety. These include the amygdala, hippocampus and the nucleus coeruleus.