Clinical Guide > Neuropsychiatric Disorders > Panic Disorder
January 2011
Panic disorder is an anxiety disorder whose essential feature is the presence of recurrent, unexpected panic attacks. Panic attacks are discrete, sudden-onset episodes of intense fear or apprehension accompanied by specific somatic or psychiatric symptoms (e.g., palpitations, shortness of breath, fear of losing control). A patient is diagnosed as having panic disorder when he or she has experienced such attacks, and at least one of the attacks has been followed by ≥ 1 month of persistent concern about additional attacks, worry about the implications or consequences of the attack, or a significant change in behavior related to the attack.
Panic disorder is classified as being either with or without agoraphobia. Agoraphobia refers to anxiety about being in places or situations from which escape might be difficult or embarrassing, or in which help might not be available in the event of a panic attack or panic-like symptoms. These situations might include being alone outside one's home, being in a crowd, being on a bridge, driving, traveling in a bus or train, or even visiting health care providers for medical appointments. The patient avoids these situations or endures them with marked distress.
The symptoms of panic disorder usually begin in late adolescence to the mid-30s and may coincide with the presentation of major depressive disorder, social phobia, or generalized anxiety disorder. Panic disorder can interfere with the ability to conduct activities of daily living. Patients with panic disorder have an increased incidence of suicide.
Symptoms may mimic those of various physical illnesses or be caused by other medical conditions (e.g., hyperthyroidism, brain tumors, adrenal tumors, heart arrhythmias, hypoglycemia, anemia). Substance or alcohol intoxication or withdrawal also may cause panic symptoms. Patients with panic symptoms should be evaluated for other causative conditions.
Major depressive disorder occurs in 50% to 65% of people with panic disorder. Major depression may precede or follow the onset of panic disorder. Patients with panic disorder therefore should be screened for depression initially and periodically thereafter (see chapter Major Depression and Other Depressive Disorders). Anxiety also commonly is experienced by persons with panic disorder; see chapter Anxiety Disorders for further information about this condition.
The patient complains of discrete periods of intense fear or discomfort in which four or more of the following symptoms developed abruptly and reached a peak within 10 minutes:
Other subjective complaints may include the following:
Panic attacks are, by definition, self-limited and they peak quickly. Symptoms that persist continuously for longer periods suggest other causes.
Ask about the symptoms indicated above and about the following:
Measure vital signs, with particular attention to heart rate (tachycardia) and respiratory rate (shortness of breath, hyperventilation). Perform a complete physical examination, including thyroid, cardiac, pulmonary, and neurologic evaluation.
During actual panic attacks, patients may have increases in heart rate, respiratory rate, or systolic blood pressure.
A differential diagnosis may include the following conditions:
Perform the following tests:
Once other diagnoses have been ruled out, consider the following treatments:
Options include cognitive-behavioral therapy, interpersonal therapy, exposure therapy, a stress-management group, relaxation therapy, visualization, guided imagery, supportive psychotherapy, and psychodynamic psychotherapy. Long-term psychotherapy may be indicated if experienced professionals are available and the patient is capable of forming an ongoing relationship. If possible, refer to an HIV-experienced therapist. The type of psychotherapy selected often will depend on the skills and training of the practitioners available in a given health care system or region. In addition, refer the patient to available community-based support. Emergency referrals may be needed for the most anxious patients and those with comorbid depression.
Patients with advanced HIV disease, like geriatric patients, may be more vulnerable to the central nervous system (CNS) effects of certain medications. Medications that affect the CNS should be started at low dosage and titrated slowly. Similar precautions should apply to patients with liver dysfunction.
Five medications have an approved indication by the U.S. Food and Drug Administration (FDA) for panic disorder. These are the serotonin reuptake inhibitors (SSRIs) and benzodiazepines listed below. For most patients, SSRIs are preferable to benzodiazepines for the treatment of panic disorder because they do not have the potential for addiction and they do not pose the same level of risk if drug interactions cause an elevation of their levels. Other medications used to treat anxiety disorders, such as serotonin/norepinephrine reuptake inhibitor (SNRI) may be considered, and some of them are less likely to interact with ARV medications. See chapter Anxiety Disorders for descriptions of these medications.
SSRI antidepressants approved for panic disorder include the following:
Benzodiazepines approved for panic disorder include the following:
Interactions may occur between certain ARVs and agents used to treat panic. Some combinations may be contraindicated and others may require dosage adjustment. Refer to medication interaction resources or consult with an HIV expert or pharmacist before prescribing.
Some ARV medications (particularly protease inhibitors [PIs]) may affect the metabolism of some SSRIs via cytochrome P450 interactions. These generally are not clinically significant, but SSRIs used concomitantly with PIs should be started at low dosages and titrated cautiously to prevent antidepressant adverse effects and toxicity. On the other hand, some PIs may decrease levels of paroxetine and sertraline, and efavirenz also lowers sertraline levels; these antidepressants may require upward titration if used concurrently with interacting ARVs.
PIs can significantly elevate the levels of clonazepam and alprazolam, resulting in the potential for severe sedation or respiratory depression. For patients receiving clonazepam or alprazolam, it is recommended that these medications be used at the lowest dosages for the shortest duration possible.
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