Introduction
Background
Anxiety disorders are common psychiatric disorders. Many patients with anxiety disorders experience physical symptoms related to anxiety and subsequently visit their primary care providers. Despite the high prevalence rates of these anxiety disorders, they often are underrecognized and undertreated clinical problems. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) classifies the anxiety disorders into the following categories:4
- Anxiety due to a general medical condition
- Substance-induced anxiety disorder
- Generalized anxiety
- Panic disorder
- Acute stress disorder
- Posttraumatic stress disorder (PTSD)
- Adjustment disorder with anxious features
- Social phobia
- Obsessive-compulsive disorder (OCD)
- Specific phobias
See Medscape's Anxiety Disorders Resource Center.
Pathophysiology
Anxiety disorders appear to be caused by an interaction of biopsychosocial factors, including genetic vulnerability, which interact with situations, stress, or trauma to produce clinically significant syndromes. In the central nervous system, the major mediators of the symptoms of anxiety disorders appear to be norepinephrine and serotonin. Other neurotransmitters and peptides, such as corticotropin-releasing factor, may be involved. Peripherally, the autonomic nervous system, especially the sympathetic nervous system, mediates many of the symptoms.
Frequency
United States
Two major studies in the United States have estimated the prevalence rates for a variety of anxiety disorders. These 2 studies are the Epidemiological Catchment Area (ECA) study1 and the National Comorbidity Survey (NCS) study2. Using these and other studies, the estimated lifetime prevalence rates for individual anxiety disorders are panic disorder (2.3-2.7%), generalized anxiety disorder (4.1-6.6%), OCD (2.3-2.6%), PTSD (1-9.3%), and social phobia (2.6-13.3%).
International
The prevalence of specific anxiety disorders appears to vary between countries and cultures. A cross-national study of the prevalence of panic disorder found lifetime prevalence rates ranging from 0.4% in Taiwan to 2.9% in Italy. A cross-cultural study of the prevalence of OCD found lifetime prevalence rates ranging from 0.7% in Taiwan to 2.5% in Puerto Rico.3
Mortality/Morbidity
- Anxiety disorders may contribute to morbidity and mortality through neuroendocrine and neuroimmune mechanisms or by direct neural stimulation, eg, hypertension or cardiac arrhythmia.
- Severe anxiety disorders may be complicated by suicide, with or without secondary mood disorders (eg, depression). Anxiety disorders have high rates of comorbidity with major depression and alcohol and drug abuse. Some of the increased morbidity and mortality associated with anxiety disorders may be related to this high rate of comorbidity. The ECA study found that panic disorder was associated with suicide attempts (odds ratio=18 compared to populations without psychiatric disorders). How much of the association of panic disorder with suicide is mediated through the association of panic disorder with mood and substance abuse disorders is unclear. Acute stress may play a role in producing suicidal behavior. Suicide attempts can be precipitated by adverse life events such as divorce or financial disaster. The effects of acute stress in producing suicidal behavior are increased in those with underlying mood, anxiety, and substance abuse problems.
- Chronic anxiety may be associated with increased risk for cardiovascular morbidity and mortality.
Race
- The ECA study found no difference in rates of panic disorder among white, African American, or Hispanic populations in the United States.
- Some studies have found higher rates of PTSD in minority populations. Some of this association may be due to higher rates of specific traumatic events (ie, assault) in minority populations.
Sex
- The female-to-male ratio for any lifetime anxiety disorder is 3:2.
Age
- Most anxiety disorders begin in childhood, adolescence, and early adulthood. Separation anxiety is an anxiety disorder of childhood that often includes anxiety related to going to school. This disorder may be a precursor for adult anxiety disorders. Panic disorder demonstrates a bimodal age of onset in the NCS study in the age groups of 15-24 years and 45-54 years. The median age of onset of social phobia in the NCS study was 16 years. The age of onset for OCD appears to be in the mid 20s to early 30s.
- New-onset anxiety symptoms in older adults should prompt a search for an unrecognized general medical condition, a substance abuse disorder, or major depression with secondary anxiety symptoms.
Clinical
History
Symptoms vary depending on the specific anxiety disorder. To rule out anxiety disorders secondary to general medical or substance abuse conditions, a detailed history and review of symptoms is essential. Review use of caffeine-containing beverages (coffee, tea, colas, Mountain Dew), over-the-counter medications (aspirin with caffeine, sympathomimetics), herbal "medications," or street drugs. Ask the patient's sleep partner about apneic episodes or myoclonic limb jerks. Concurrent depressive symptoms are common in all of the anxiety disorders. Severe anxiety disorders may produce agitation, suicidal ideation, and increased risk of completed suicide. Always ask about suicidal ideation or suicidal intent.
- Panic disorder is characterized by recurrent panic attacks (ie, periods of intense fear of abrupt onset peaking in intensity within 10 min). Four of the following must be present for a panic attack:
- Palpitations, pounding heart, or accelerated heart rate
- Sweating
- Trembling or shaking
- Shortness of breath or dyspnea
- Sensation of choking
- Chest pain or discomfort
- Nausea or abdominal distress
- Feeling dizzy, unsteady, lightheaded, or faint
- Derealization or depersonalization
- Fear of losing control or going crazy
- Fear of dying
- Paresthesias
- Chills or hot flashes
- Although not a diagnostic feature, suicidal ideation and completed suicide have been associated with panic disorder.
- Generalized anxiety disorder is characterized by excessive anxiety and worry. Worrying is difficult to control. Anxiety and worry are associated with at least 3 of the following symptoms:
- Restlessness or feeling keyed-up or on edge
- Being easily fatigued
- Difficulty concentrating or mind going blank
- Irritability
- Muscle tension
- Sleep disturbance
- Although not a diagnostic feature, suicidal ideation and completed suicide have been associated with generalized anxiety disorder.
- OCD is characterized by obsessions or compulsions. Obsessions or compulsions must be recognized as unreasonable or excessive and must cause marked distress.
- Obsessions include all of the following:
- Recurrent and persistent thoughts, impulses, or images that are intrusive and knowingly inappropriate and cause anxiety or distress
- Thoughts, impulses, or images that are not simply excessive worries about real-life problems
- Attempts are made to ignore or suppress thoughts.
- Thoughts, impulses, or images are recognized as being the product of the mind and not imposed from an outside force.
- Compulsions include the following:
- Repetitive behaviors, such as handwashing, ordering, and checking, that people feel are driven and must be carried out and occur to such an extreme that a person's ability to function is impaired.
- Behaviors or mental acts are done to reduce distress or anxiety.
- Obsessions include all of the following:
- Social phobia
- Marked and persistent fear of social or performance situations to the extent that a person's ability to function at work or in school is impaired.
- Exposure to social or performance situation always produces anxiety.
- Fear/anxiety recognized as excessive
- Social or performance situations are avoided or endured with intense anxiety.
- Avoidance behavior, anticipation, or distress in the feared social or performance setting produces significant impairment in functioning.
- PTSD is a severe trauma that is experienced that includes (1) actual or threatened death or serious injury or threat to personal integrity of self or others and (2) responses that include intense fear, helplessness, or horror. (Life-threatening experiences and the attendant loss of control are key elements.)
- Persistent reexperience of the event occurs by at least 1 of the following:
- Recurrent and intrusive recollections
- Recurrent distressing dreams/nightmares
- Feelings of reliving traumatic event, ie, flashbacks
- Intense psychologic distress with internal or external cues to the trauma
- Physiological reactivity on exposure to trauma cues
- Persistent avoidance of stimuli of trauma and numbing/avoidance behavior demonstrated by at least 3 of the following:
- Avoidance of thoughts or conversation related to the trauma
- Avoidance of activities, places, or people related to the trauma
- Amnesia for important trauma-related events
- Decreased participation in significant activities
- Feeling detached or estranged from others
- Restricted affect
- Foreshortened sense of the future
- Persistent symptoms of increased arousal demonstrated by 2 or more of the following:
- Difficulty staying or falling asleep
- Irritability or anger outbursts
- Difficulty concentrating
- Hypervigilance
- Exaggerated startle response
- Although not a diagnostic feature, suicidal and homicidal ideation have been associated with PTSD.
- Persistent reexperience of the event occurs by at least 1 of the following:
Physical
- Tremor
- Tachycardia
- Tachypnea
- Sweaty palms
- Restlessness
Causes
- First, evaluate for anxiety due to a known or unrecognized medical condition.
- Most presenting anxiety disorders are functional psychiatric disorders.
- Substance-induced anxiety disorder (over-the-counter medications, herbal medications, substances of abuse) is a diagnosis that often is missed.
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References
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Further Reading
Keywords
generalized anxiety disorder, panic disorder, phobia, agoraphobia, obsessive-compulsive disorder, OCD, stress, anxiety neurosis, nervousness, posttraumatic stress disorder, PTSD, substance-induced anxiety disorder, specific phobias, social phobia, adjustment disorder, acute stress disorder, major depression, separation anxiety, substance abuse disorder, recurrent distressing dreams, recurrent distressing nightmares, difficulty staying asleep, exaggerated startle response, hypervigilance, difficulty concentrating, anger outbursts, irritability, difficulty falling asleep, sweaty palms, restlessness
