Panic attacks occur for no apparent or clear reason. Their causes are unknown. They may happen at the most unexpected times and may strike you unexpectedly. They are sudden and spontaneous, and as such might occur when you are under severe stress or when you are quite relaxed and in restful sleep. They might occur due to your being in a situation that you intensely fear facing or experiencing, whether real or anticipated and imaginary. In other words, your phobia (irrational fear) or phobias might trigger them. You may be alone or in the midst of doing some people, you may be doing nothing or something important, when the panic attacks might occur, without any sort of warning. For instance, you might suffer a panic attack while driving or shopping or doing something else like riding in an elevator, without you having even an inkling of what is happening to you.

According to the American Psychological Association, a panic attack clearly comes without any kind of warning as 'a sudden surge of overwhelming fear'. It is quite common for most people to experience a feeling of being 'stressed out', but panic attacks come with far greater intensity and suddenness. Intense fear and abruptness most usually qualify panic attacks.

They are sometimes attributed to hereditary factors. If someone in your family has had a history of panic attacks, you might be prone to having them too. Critical transitions in life, whether associated with intense happiness or distress, like marriage or divorce, death, job loss or some highly stressful happening could be related to panic attacks in certain cases.

Some people are under the misconception that a panic attack and anxiety are similar in nature or that intense anxiety leads to a panic attack. While it may be true that in cases of people suffering from some anxiety disorder, they are likely to have panic attacks, but panic attacks do not always occur because of some anxiety disorder. Panic attacks are usually sudden and short-lived, while anxiety develops more slowly and remains as a nagging trouble for a much longer time. However, in case a panic attack occurs in a person suffering from an anxiety disorder, it is possible to prevent recurrence of the panic attack by attending to the treatment of the anxiety disorder. Similarly, when panic attacks co-occur with some other mental or physical disorders like chronic fatigue or irritable bowel syndrome, treating these other disorders will help in the treatment of panic attacks, although they do not count as causes.

Extensive researches conducted with the aim of determining what causes panic attacks have not been conclusive in their results. They have only left us with some pointers. One theory is that some people have a genetic pre-disposition to panic attacks. Another mentions some kind of a biological malfunction or imbalance might cause a panic attack. And according to yet another, psychological factors that include various irrational fears, intense stress resulting from some heart-breaking grief or loss might trigger a panic attack.