Anxiety disorders are surprisingly common and often go undiagnosed.Their ability to mimic numerous medical conditions adds to the challenge.

Anxiety disorders make up the most common category of psychiatric conditions, affecting about 17 million to 19 million American adults every year.

One of the challenges in diagnosing the disorders is that most patients present with physical symptoms rather than psychological complaints.1 Symptoms such as chest pain, irritable bowel, unexplained dizziness, headache, and chronic fatigue are common, but diagnostic testing reveals no underlying physical cause. Unfortunately, in these cases, the diagnosis of an anxiety disorder is also missed. Anxiety disorders often coexist with medical conditions; in some patients, anxiety can aggravate and/or contribute to the medical condition, while for others, the medical condition is the underlying cause.

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The Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) lists 11 types of anxiety disorders (Table 1). While each type has its defining characteristics, there are common presenting features, including physical and psychological signs and symptoms (Table 2). For example, a patient with generalized anxiety disorder (GAD) very often presents with intense feelings of dread or worry and an inability to control the worry.

The patient’s thinking and emotional pattern of dread and worry are persistent and dominate his or her life. The emotional distress is disproportionate to what the situation demands. A diagnosis of GAD is made when symptoms present more days than not for at least six months and at a level that interferes with concentration. The patient’s ability to function in social or occupational situations is impaired. Physical complaints often include fatigue, difficulty sleeping, feeling on edge, irritability, and muscle tension.

Anxiety disorders: Beyond normal fear and worry

Fear and worry are normal emotions. And when appropriate for the situation, these emotions create the drive, energy, and motivation needed to respond to the demands of the moment. For example, fear, with its associated adrenaline rush, is helpful if one is in danger. An anxiety disorder is diagnosed when the worry and fear are excessive in terms of intensity, frequency, and duration and when the fear and/or worry are disproportionate precipitating factors. Thus, abnormal fear could be characterized by the tendency to be overly fearful of a specific object, as seen in phobias, or fear related to a situation, as seen in social anxiety. In the case of GAD, the individual is overly fearful a large percentage of the time, and the fear or excessive worry tends to be about anything and everything.

There are several anxiety disorders, and it is very common for a patient to present with more than one. Anxiety disorders also occur concomitantly with other mental illnesses, such as bipolar and personality disorders, major depression, and substance abuse.

Panic disorder

According to the DSM-IV-TR, panic disorder is characterized by spontaneous panic attacks and may occur alone or be associated with agoraphobia. A major feature of panic disorder is a fear of having another attack rather than the specific fear of a situation. With agoraphobia, there is a situational component to the panic attack. There are two distinct types of panic attack: spontaneous (non-phobic) and cue-induced (phobic). From a clinical perspective, it is important to accurately identify the type of panic attack because they differ in their physiologic nature and symptom presentation. There is also a significant difference in the treatment approach for each type.

Spontaneous panic attacks stem from an abnormal oversensitivity to carbon dioxide (CO2), what is called the “suffocation alarm.” The major symptoms of spontaneous panic attack are respiratory—shortness of breath, chest discomfort, palpitations, and choking or suffocation sensations.2 Spontaneous panic attacks often occur during relaxation and non-dream sleep.

Treatment therefore does not include benzodiazepines. Instead, it focuses on education and may include medications that help decrease sensitivity to the “suffocation alarm,” such as tofranil, anafranil, or a selective serotonin reuptake inhibitor (SSRI). Relaxation exercises would not be indicated as a behavioral intervention because they tend to decrease respirations, resulting in an increase in CO2, which can lead to a panic attack. Treatment for spontaneous panic attacks should include education on the physiological mechanism involved.

For women who suffer from spontaneous panic attacks, it is important to inform them that they are more vulnerable when they are premenstrual and immediately after childbirth. Vulnerability during these times is related to the sudden drop in progesterone levels. Progesterone acts to decrease CO2 levels in the brain by increasing respiratory rate. Thus when progesterone decreases, CO2 in the brain rises, resulting in an increased vulnerability to panic.

A cue-induced (phobic) panic attack is fear-based triggering of an adrenaline stress response (fight or flight). The symptoms are rapid heart rate, light-headedness, sweating, and trembling. Because of the anticipatory nature of the anxiety, benzodiazepines would be appropriate, along with education, relaxation exercises, and cognitive behavioral therapy (CBT).

Social phobia: Social anxiety disorder

Social anxiety disorder (SAD) is among the most common mental disorders on a lifetime basis. Prevalence ranges from 12% to 14% of the population.3 The hallmark of SAD is the marked and persistent fear of one or more social or performance situations. There is the fear that one will act in a way that will be humiliating or embarrassing. In some cases, exposure to the feared situation may lead to a (cue-induced) panic attack.

Generalized SAD (a subtype) is characterized by fear and/or avoidance of multiple social situations and is the most common form of SAD among patients presenting to a primary health-care provider.3 The onset is usually in childhood or early adolescence and is believed to stem from genetic as well as environmental factors. Research has shown that parents who have SAD tend to be overprotective and are overly sensitive to social disapproval themselves.4

SAD treatment

First-line treatments for SAD include SSRIs. Paroxetine 20-50 mg/day, sertraline 50-200 mg/day, and venlafaxine 75-225 mg/day have demonstrated effectiveness and are FDA-approved for the treatment of SAD. If a patient is resistant to SSRIs, benzodiazepines can be considered (e.g., clonazepam 0.25-3.0 mg/day). Calcuim channel blockers, gabapentin (900-3,600 mg/day), and pregabalin (600 mg/day) are also options for treatment-resistant SAD.5 CBT is indicated to address fears and avoidance behaviors. For specific situations, such as performance anxiety, a beta blocker, such as propranol 10-20 mg, can be effective.

Medical mimics

A physical condition is frequently the underlying cause of the emotional symptoms. Therefore, anyone presenting with symptoms of anxiety should have a thorough evaluation to rule out the possibility of a physical cause. Be alert for the following characteristics of a medical mimic:

1. A history that does not fit. Be suspicious if a patient presents with symptoms of anxiety but has no significant history of the disorder, no evidence of a significant life stress, and no family history of anxiety disorders.
2. Onset of symptoms occurs later in life. Many of the anxiety disorders can be traced to childhood, adolescence, or early adulthood. Therefore, be suspicious of symptoms that emerge later in life.
3. Anxiety symptoms emerge along with a recent onset of headache, loss of neurologic or cognitive function, unusual perceptions (e.g., tingling, dissociation, visual disturbances, paranormal experiences, or hallucinations [especially visual, olfactory, or tactile]).
Symptoms may be the result of a neurologic disorder. In addition, brain tumors can be the underlying cause of hallucinations and sensory disturbances. Occipital-lobe tumors have been known to produce visual hallucinations, and parietal-lobe tumors may produce sensory disturbances.
4. Ask about any drug use, including OTC and herbal agents.2 Anxiety symptoms can result from a number of drugs, including thyroid medications, theophylline, and albuterol. Food additives, such as monosodium glutamate, and herbal preparations, such as ginkgo biloba, can also be contributing factors, as can caffeine.

Identifying medical mimics

Many medical conditions can mimic psychiatric disorders. The mnemonic THINC MED is helpful in identifying the major categories of medical mimics2 (Table 3).

Tumors. These often present with a range of psychiatric symptoms. For example, pheochromocytomas produce adrenaline and often present as anxiety or panic attacks. However, episodes of panic related to pheochromocytomas include severe headache and are not accompanied by the catastrophic thinking seen in cue-induced panic or the respiratory symptoms evident in spontaneous panic attacks.

Hormones. Hyperthyroidism may present with symptoms that mimic anxiety disorders. Such physical symptoms as increased sensitivity to heat, weight loss, restlessness, difficulty sleeping, and tremor suggest a physical cause for the anxiety-like symptoms. In some women, estrogen can produce anxiety symptoms.

Infectious diseases. Some infectious diseases may also present with psychiatric symptoms. For example, untreated streptococcal infection may lead to onset of tics (Sydenham’s chorea) that resemble the symptoms of obsessive-compulsive disorder. Symptoms resolve with treatment of the infection. Lyme disease can be associated with psychiatric symptoms, including anxiety.

Nutrition. Vitamin deficiency or excess, malabsorption, and poor nutrition can mimic a range of emotional disorders. Vitamin B12 deficiency especially can present with anxiety symptoms and, in some cases, panic attacks.

Central nervous system. Head trauma—even when it is mild—can result in psychiatric symptoms, including those of anxiety.

Miscellaneous. Wilson’s disease, an inherited disorder that interferes with the metabolism of copper, can present with features similar to schizophrenia, bipolar disorder, and anxiety disorders. The psychiatric symptoms often begin during adolescence. Wilson’s disease is progressive in nature, causing damage to the liver and brain. A distinctive physical characteristic is a brownish ring surrounding the cornea of the eye.

Electrolyte abnormalities and environmental toxins. Long-term exposure to insecticides (organophosphates) can result in anxiety and restlessness.

Drugs. OTC, homeopathic, prescribed, or illicit drugs can produce a wide range of psychological symptoms. Alcohol withdrawal, cocaine, and stimulants can also result in anxiety symptoms.

Treatment of anxiety disorders

The treatment of anxiety disorders should begin with a consideration of the type of symptoms (emotional, cognitive, or physical) and their nature, severity, intensity, frequency, and duration. Psychiatric conditions and/or medical conditions that frequently occur together should also be taken into account. Treatment choices will often depend partly on the patient’s preference.

First-line medications for treating GAD are similar to those for SAD: SSRIs or serotonin norepinephrine reuptake inhibitors. Benzodiazepines may be useful for patients who experience anxiety symptoms when starting either of these or for patients who have failed to respond. Supportive counseling, insight-oriented psychotherapy, CBT, and group therapy may also be helpful. Education aimed at healthy lifestyles, proper nutrition, exercise, and minimizing caffeine is recommended.

While patients presenting with spontaneous panic attacks may benefit from an SSRI or SNRI and education, use of a benzodiazepine would not be indicated. In contrast, patients with cue-induced panic attacks may benefit from an SSRI or SNRI and may also require a benzodiazepine in severe cases. Guidance in the area of stress management and coping skills is also of benefit.

Ms. Hentz is associate dean of undergraduate nursing programs at the Thomas Jefferson University School of Nursing in Philadelphia.


1. Stern TA, Herman JB, eds. Massachusetts General Hospital Psychiatry Update and Board Preparation. New York, N.Y.: McGraw-Hill Professional Publishing; 1999:395-419.

2. Hedeya R. Understanding Biological Psychiatry. New York, N.Y.: W.W. Norton & Company; 1996:100-204.

3. Stein MB. An epidemiologic perspective on social anxiety disorder. J Clin Psychiatry. 2006;67 Suppl 12:3-8.

4. Culpepper L. Social anxiety disorder in the primary care setting. J Clin Psychiatry. 2006;67 Suppl 12:31-37.

5. Davidson JRT. Pharmacotherapy of social anxiety disorder: what does the evidence tell us? J Clin Psychiatry. 2006;67 Suppl 12:20-26.