Dear Doctor: Could you explain panic attacks? I never knew what people were talking about until a few months ago, while sitting at the computer. I felt as if I had stopped breathing; I thought I was dying. I ended up in the ER, but no problems were found. This has happened several times since, and I want my life back.

Dear Reader: Panic attacks are truly a scary experience, especially if you’ve never had them before. Many of the symptoms are similar to those of a heart attack, causing people to seek immediate attention in an urgent care department or emergency room. The symptoms, which develop suddenly, can include chest pain, heart palpitations, sweating, nausea, shortness of breath, lightheadedness and, for many, the feeling that they’re going to die.

Such attacks are surprisingly common. One-third of people have at least one panic attack during their lifetime. Those who experience recurrent panic attacks not related to generalized anxiety, depression, obsessive-compulsive disorder or post-traumatic stress disorder have what is termed panic disorder. People with panic disorder have a persistent worry about having another panic attack and the consequences of future attacks. That leads them to avoid situations that may induce panic attacks, which, in turn, leads to a profound alteration in quality of life. Panic disorder affects nearly 3 percent of the population, ages 15 to 54.

People with panic disorder often report an increase in stressful life events over the past year and, even more often, within the past month. Genetic factors also play a role. A person who has a first-degree family member with panic disorder is three times more likely to develop the disorder compared to people without such a tie. Further, an identical twin is five times more likely to have anxiety and panic if his or her twin has the disorder.

The symptoms of panic attacks are essentially a normal “fight or flight” response to a very stressful situation, such as an encounter with a lion, tiger or grizzly bear. However, panic attacks occur without the lion, tiger or bear.

Some experts hypothesize that panic attacks are abnormal central nervous system responses to even the most mundane stimuli. Such responses arise in the brain’s limbic system, which normally processes sensory information into emotional responses, behavior and memory. The hyperresponsiveness to sensory inputs — and even the inputs from one’s own thinking — leads to a poor regulation of the autonomic nervous system, which controls heart rate, the contraction of the heart, blood pressure, the gastrointestinal system and sweating. MRI studies have confirmed alterations in the limbic system in people with panic disorder.

Panic attacks can also be precipitated by stimulants such as caffeine, cocaine and amphetamine as well as withdrawal from alcohol, opiates or benzodiazepines like Valium, Ativan and Xanax. Although patients sometimes use benzodiazepines to stop a panic attack, these medications can induce rebound panic when the drug is out of the system, making them a poor treatment option.

Cognitive behavioral therapy shows the greatest sustained benefit in stopping panic attacks, because it can alter the underlying brain responses. Selective serotonin reuptake inhibitor medications also can help.

In summary, starting therapy and possibly medication will be the first steps in getting your life back.

Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.