A common component of an anxiety disorder is the panic attack. A panic attack may be a familiar experience to many, as 15% of people have reported the occurrence of one over their lifetime. It is defined as a discrete period of intense fear or discomfort in the absence of real danger that is accompanied by 4 of 13 somatic or cognitive symptoms. This attack can occur suddenly and peak quickly, usually within 10 minutes or less. A panic attack can be unexpected or situational in nature. A partial panic attack incorporates 1 to 3 of the characteristic symptoms of a panic attack.

This article will utilize the panic attack as a model for better insight into all of the anxiety disorders. If one can understand the symptomatology and characteristics of a panic attack, one can apply this knowledge to all of the anxiety disorders if certain modifications and limitations of this model are considered.

In a panic attack, a message of misperceived, severe danger is sent from the brainstem area to several other areas of the brain, including the cortex. There the message is intercepted as an acute lack of oxygen in the body, prompting a sense of physiological emergency and imminent threat to life. In fact, however, this message is incorrect; physiological sensors have misinterpreted the amount of carbon dioxide (CO₂) in the bloodstream (as “too much,” when levels are normal) and consequently misinterpreted the amount of oxygen O₂ in the bloodstream (as “too low,” when levels also are normal). In a panic attack, sensors have assessed that conditions in the body will soon be incompatible with life; thus, the sensors have sent emergency requests to other organs to respond to the “emergency.” As a result, the body attempts to (1) obtain more oxygen by increasing the depth and rate of breathing, (2) disperse oxygen to all parts of the body by increasing heart rate and volume, (3) prevent overheating the body by increasing perspiration, and (4) prepare the body for action by shifting blood flow away from normal vegetative functions and toward the muscles.

Despite the body’s misguided shift into physiological emergency preparedness, carbon dioxide and oxygen levels are normal. This misperception is accompanied by massive release of the neurotransmitters norepinephrine (NE) and epinephrine (E) to help the body prepare for this “emergency”…none of which is needed. This aberrant signal, or CO₂ hypersensitivity, is also known as the suffocation false-alarm theory. The false signal regarding the body’s CO₂/O₂ balance can occur anytime, such as when one is eating, relaxing, working, sleeping, or doing any other human activity, whether safe or dangerous, stressful or relaxing.

Panic Disorder (With and Without Agoraphobia)

Panic disorder (PD) is defined as a condition in which recurrent, unexpected panic attacks occur, followed by at least one month’s duration of persistent concern about having more attacks, or worry about the effects of having a panic attack (e.g., having a heart attack or “going crazy”) or a major change in behavior because of the attacks. The attacks are not related to the direct effects of a drug/medication or a known medical condition or accounted for by another known psychiatric disorder.

A number of possible medical conditions must be considered in the differential diagnosis of panic disorder. Anemia, dysrhythmias, asthma, transient ischemic attacks, and hyperthyroidism constitute a few of these conditions. Drugs capable of inducing panic attacks include most central nervous system (CNS) stimulants such as cocaine, amphetamines, and methylphenidate, as well as all antidepressants. Caffeine, nicotine, hallucinogens, and bronchodilators, such as albuterol, can also produce a panic attack. Nonprescription medications such as pseudoephedrine (found in decongestants) and ephedrine (found in herbal products) can also cause a panic attack.

The proposed hypotheses for the etiology of panic disorder include possible dysregulation of the locus ceruleus, hypersensitivity of 5-HT autoreceptors, abnormal cholecystokinin function,and the CO2 hypersensitivity theory presented earlier in this article.

Characteristics of panic disorder occur more frequently in women and have a bimodal age of onset, with the first peak occurring in late adolescence and the second one in the patient’s mid-30s.Patients with untreated panic disorder have been found to have increased rates of depression. Suicide attempts have been reported in 12% of patients with panic attacks and 20% of those with panic disorder.

Patients with panic disorder can develop agoraphobia, which is avoidance and anxiety about situations or places from which escape may be difficult or embarrassing, or help would be unavailable if a panic attack were to occur. Patients typically avoid these situations partially or completely or they may tolerate and endure them with extreme anxiety.