Medical Mimics of Anxiety Disorders
Karen Elmore MD
Robert K. Schneider MD
Revised 5-11-2001 by Robert K. Schneider MD

Substance-induced disorders and medical illness presenting with anxiety
symptoms need to be considered before the diagnosis of any anxiety disorder
can be made. There is no lab test or imaging study that definitively makes a
psychiatric diagnosis. The physician is reliant upon her clinical judgment and
index of suspicion to distinguish between anxiety disorders and the medical
problems that mimic them. Pollard and Lewis suggest the following guidelines.
A medical or substance induced cause of anxiety is more likely when the first
presentation is after age 40, there is fluctuation in the level of consciousness, or
there is evidence of autonomic instability. An anxiety disorder is more likely
when the patient is concerned about losing control, has a family history of anxiety
problems, first presents between ages 18 and 45, has a recent or anticipated life
event, or has agoraphobia.

Substance Abuse
When evaluating a patient for anxiety, it is important to take a good substance
abuse history. Substances causing anxiety may be over the counter,
prescription, or illegal. These include ephedrine and pseudoephedrine, nicotine,
caffeine, cocaine, and 3,4-methylenedioxymethamphetamine (MDMA or
ecstasy). An increasing number of women are taking herbal supplements that
have side effects such as nervousness and insomnia. These include St. John’s
wort, ephedra (ma huang), and ginseng (Avila 1999). Withdrawal of alcohol,
opiates or benzodiazepines should also be considered. Patients who take
alprazolam, a short acting benzodiazepine, to treat anxiety may have withdrawal
symptoms between doses. Caffeine is a very commonly ingested substance and
somatic manifestations of caffeinism are similar to symptoms of anxiety
disorders. These include diuresis, insomnia, withdrawal headache, diarrhea,

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anxiety, tachycardia, and tremulousness (Victor 1981). Clinical experience
shows that some women take methylphenidate prescribed to their children for
appetite suppression, depression, and decreased concentration.

While substances may cause anxiety, women with anxiety disorders commonly
have comorbid substance abuse. In one study, women with alcohol disorders
were two to three times more likely than other women to have depression or any
anxiety disorder (Brady 1999). One study of people with cocaine dependence
found anxiety disorders to be twice as prevalent in women as in men
(Rounsaville 1991).

Cardiac
Supraventricular tachycardia (SVT) has many clinical similarities to panic
disorder. One retrospective study by Lessmeier and Gamperling surveyed 107
patients with known SVT in an electrophysiology office. In this cohort, 88%
experienced four or more symptoms of panic and 67% fulfilled the DSM-IV
criteria for panic disorder. The diagnosis of SVT was initially unrecognized in
55% and remained so for a median of 3.3 years. Before the SVT was
discovered, women were about twice as likely as men to carry the diagnosis of
panic or anxiety. This study also found that an event monitor was much more
likely than a Holter monitor to make the diagnosis. Anxiety symptoms resolved in
86% after appropriate treatment for SVT. Other cardiac problems that may
present with anxiety symptoms include myocardial infarction (MI), coronary
insufficiency, congestive heart failure, and anemia. Evidence suggests that
patients with MI and lactic acidosis may have a catecholamine release from the
locus ceruleus causing feelings of anxiety (Gallerani 1995).

Pulmonary
While asthma attacks and panic attacks share many of the same symptoms, it is
usually possible to distinguish between the two by history. One study found that
when wheezing, coughing and mucous production were present, asthma is the

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most likely diagnosis (sensitivity of >90%, specificity of >70%). However, it can
be more challenging to diagnose anxiety disorders in patients with known asthma
or chronic obstructive pulmonary disease. Panic is more common in these
patients than in normal controls (Perna 1997). Co-occurrence of untreated panic
and obstructive lung disease leads to more frequent use of as needed
medications and steroids, more hospital admissions, and longer hospital stays
(Carr 1999).

Endocrine
Perhaps the most well known medical mimic of anxiety disorders is
hyperthyroidism. The epidemiology and symptomatology of both disorders are
similar. Women are ten times more likely than men to have hyperthyroidism, and
the disease is most common at ages 30-40 (Wallis 1998). It is reasonable to
check a screening TSH on all patients who present with symptoms of anxiety.
Menopause is another common cause of insomnia, fatigue, and irritability. A
careful history is required to differentiate hot flashes and other symptoms of
menopause from anxiety disorders.

Pheochromocytoma causes catecholamine release and may be misdiagnosed as
anxiety (Starkman 1990). Clues pointing to pheochromocytoma include
hypertension, abdominal pain, and anxiety that is refractory to treatment.
Hypertension can be persistent or present only during a catecholamine surge.
Therefore, between attacks, the physician may see evidence of the long-term
consequences of hypertension, such as retinopathy and congestive heart failure,
in the absence of elevated blood pressure (Archer 1999).

Consider congenital adrenal hyperplasia (CAH) in women with anxiety that also
have hirsuitism, infertility, and irregular menses. CAH is an autosomal recessive
deficiency of steroidogenic enzymes that is present in 1% of the population. This
disorder causes accumulation of dehydroepiandrosterone (DHEAS), an
antagonist of the gamma-aminobutyric acid A (GABA-A) receptor in the brain,

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leading to potent anxiogenic effects. One study looked at twelve patients with
refractory anxiety disorders and CAH. Anxiety levels decreased by 55% after
appropriate treatment for CAH (Jacobs 1999).

Other medical conditions to consider include hypoglycemia, which is seen most
commonly in patients on diabetes medication. Hypercalcemia and hypocalcemia
of an abnormal parathyroid gland may present with anxiety and irritability. Also
consider Addison’s disease, Cushing’s syndrome, pulmonary embolus, temporal
lobe epilepsy, vertigo and carcinoid when evaluating a patient with unexplained
anxiety symptoms.

Bibliography

Archer TP, Mazzaferri EL. Intermittent anxiety attacks in a young man. Hosp
Pract 1999;34(4):136-7, 141-2

Avila J, Fetrow CW. Professional’s Handbook of Complementary and Alternative
Medicines. Springhouse, PA: Springhouse Corp, 1999

Brady KT, Randall CL. Gender differences in substance use disorders.
Psychiatric Clinics of North America 1999; 22(2):241-53

Carr RE. Panic disorder and asthma. J Asthma 1999; 36(2):143-52

Gallerani M, Manfredini R, Mele D, et al. Can panic disorder be considered as
an angina equivalent? Eur Heart J 1995;16(12):2013-4

Jacobs AR, Edelheit PB, Coleman AE, Herzog AG. Late-onset congenital
adrenal hyperplasia: a treatable cause of anxiety. Biol Psychiatry 1999;
46(6):856-9

Lessmeier TJ, Gamperling D, Johnson-Liddon V, et al. Unrecognized
paroxysmal supraventricular tachycardia. Potential for misdiagnosis as panic
disorder. Arch Intern Med 1997;157(5):537-43

Perna G, Bertani A, Politi E, et al. Asthma and panic attacks. Biol Psychiatry
1997;42(7):625-30

Pollard CA, Lewis LM. Managing panic attacks in emergency patients. J Emerg
Med 1989; 7(5):547-2

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Rounsaville BJ, Anton SF, Carroll K, et al. Psychiatric diagnoses of treatment-
seeking cocaine abusers. Arch Gen Psychiatry 1991;48:43-51

Starkman MN, Cameron OG, Nesse RM, Zelnik T. Peripheral catecholamine
levels and the symptoms of anxiety: studies in patients with and without
pheochromocytoma. Psychosom Med 1990; 52(2):129-42

Victor BS, Lubetsky M, Greden JF. Somatic manifestations of caffeinism. J Clin
Psychiatry 1981;42(5):185-8

Wallis LA, et al. Textbook on Women’s Health, 1998. Lippincott-Raven,
Philadelphia, PA, pp 527-8

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Document Outline

• Cardiac
• Pulmonary
• Endocrine
  • Bibliography

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