Differential diagnosis of anxiety

As with many psychiatric symptoms, it is important to determine whether anxiety is a reflection of a situational stressor, psychiatric disorder, character pathology, or medical etiology. Sometimes anxiety is focused on a system that is related to a medical problem.

Although extremely anxious people may initially appear to be somewhat delirious, the mental status examination should sort that out in short order. It is especially important to be cognizant of substance use disorders as an underlying cause of anxiety. For example, substance use among older adults has been increasing.

It is important also to distinguish anxiety disorders from agitated depression, delirium, psychosis, or delusional disorders. Anxiety disorders often co-exist with other Axis I disorders (especially depression).

★It is important to consider three potential causes of anxiety:

1. Is anxiety a psychological reaction to medical illness?
2. Does the anxiety reflect the effects of a substance?
3. Does the medical illness itself directly cause the anxiety?

The first potential cause is rather self-explanatory and can occur in contexts such as waiting for the outcome of a test, etc.

Substance use

Substances can be a major factor in anxiety disorders. Caffeine and other stimulants are associated with anxiety. Caffeine is not only present in coffee, but noDoz, over the counter weight loss preparations, and Excedrin. Pseudoephedrine can precipitate anxiety, even when used in the form of nasal sprays. Needless to say, methamphetamines can be associate with anxiety as well.

Medical conditions

Medical conditions that are often associated with anxiety in the hospital setting include:

• Thyroid disorders (commonly hyperthyroidism and rarely hypothyroidism) - difficult to distinguish from anxiety disorders, but some clues that hyperthyroidism is present include persitent tachycardia, warm, dry palms (as opposed to cold and clammy), and fatigue with a desire to be active.
• Parkinson's disease - anxiety is fairly common
• Pulmonary disease - Patients with asthma and COPD have a higher prevalance of panic disorder than the general population. Uncertainty may contribute to anxiety in asthma and CO2 inhalation can precipitate panic attacks in individuals with panic disorder. Finally, pulmonary emoboli may lead to increased anxiety.
• After stroke - Anxiety after stroke is often seen as part of post-stroke depression, but can sometimes appear alone. When patients experience anxiety after a stroke, it can persist and evolve into Generalized Anxiety Disorder: after 3 months, 31% of patients had GAD and 19% had GAD after 3 years. Anxiety is often associated with right hemspheric lesions where as depression and depression + anxiety are associated with left hemispheric lesions.
• Seizures - Complex partial seziares may be accompanied by symptoms of panic disorder.
• Metabolic conditions (hypocalcemia, hypomagnesemia)

Medications

There are many medications that can cause anxiety and it is best to examine the patient's medication list with an eye toward this. Of particular note are certain medications that may not be commonly thought of in this context, such as conjugated estrogens, ethinyl estradiol. With respect to antipsychotics, sometimes the akathisia often associated with first generation antipsychotics, occasionally associated with second generation antipsychotics, can present as anxiety.