Causes of Panic Disorder
There are two types of theories about what causes panic disorder: biological and behavioral.
Biological theories are based on the idea that the brain has a natural alarm system that somehow malfunctions because of genetic or environmental circumstances, causing panic. All parts of the brain are intricately connected and are intricately interactive, so it is likely that, if the biological theories prove to be correct, more than one area would be affected in patients with panic disorder.
Currently, four areas of the brain are under investigation: the locus ceruleus, gamma-aminobutyric acid (GABA), septohippocampal interactions, and the ventrumedulla.
- The locus ceruleus is a cluster or nerves in the brain stem that produces and uses the neurotransmitter norepinephrine. The locus ceruleus nerves are activated during states of heightened vigilance and release norepinephrine into many areas of the brain.
- GABA neurons play important roles in the hypothalamus and the brain stem. Low levels of GABA may produce symptoms such as sweating, hypertension, tachycardia, and shortness of breath.
- Septohippocampal interactions involve neurons that connect the septal area of the brain to the hippocampus. There are many cells in the hippocampus that produce and use GABA. A substantial number of locus ceruleus cells that produce norepinephrine also connect to the hippocampus.
- Regulation of heart function is centered in the ventromedulla (part of the brain stem). When stress or exercise stimulates the hypothalamus, a signal is sent to the medulla to stimulate the cardiac nerves to increase the number of heartbeats per minute. Any dysfunction of the hypothalamus or medulla could produce some of the cardiac symptoms of a panic attack (e.g., rapid heart rate, palpitations).
Behavioral theories focus on the nature of panic attack as an irrational response to a non-threatening stimulus. These theories hold that once the cause is identified and analyzed rationally, the person can learn to respond normally to the situation or trigger that causes panic.
Panic Disorder Signs and Symptoms
The defining characteristic of panic disorder is the panic attack. A person's first panic attack may be provoked by a situation, but in panic disorder, subsequent attacks occur unexpectedly and without provocation.
In the Diagnostic and Statistical Manual of Psychiatric Disorders, 5th ed., The American Psychiatric Association identifies several symptoms that commonly occur during a panic attack:
- Abdominal distress (diarrhea, nausea)
- Chest pain or discomfort
- Chills or hot flashes
- Fear of dying
- Fear of losing control or going crazy
- Feeling faint, dizzy, lightheaded, unsteady
- Feeling of choking
- Feeling of unreality or of being detached from oneself
- Numbness or tingling sensations
- Palpitations, pounding heart, racing heartbeat
- Shortness of breath, feeling smothered
- Trembling or shaking
Four or more of the symptoms must occur abruptly and reach their peak intensity within 10 minutes for the episode to be considered a panic attack.
The person with panic disorder worries about the next attack. This is called anticipatory anxiety. Anticipatory anxiety can cause people to avoid situations in which they might have a panic attack. Avoiding these situations can drastically disrupt normal daily activities like grocery shopping or driving to work.
About 40 percent of people with panic disorder develop agoraphobia. Agoraphobia is the anxiety about or avoidance of specific places or situations that may cause a panic attack. People with panic disorder with agoraphobia become very inhibited and afraid of most situations such as the following:
- Being in public places
- Driving in traffic, through tunnels, or on bridges
- Eating in public places
- Waiting in line
Some people with agoraphobia never leave their house or apartment. Others stop going out alone and only go out with someone they trust.