As with many conditions that affect your mental health, the exact cause of panic disorder is not yet fully understood.

It is thought that the disorder is most likely caused by a combination of physical and psychological factors. Some of these factors are outlined below.

• Stressful or traumatic experiences in your life, such as a bereavement, can sometimes trigger feelings of panic and anxiety. These feelings may be apparent soon after the event, or they may unexpectedly be triggered years later.
• Having a close family member with panic disorder may increase your risk of developing the condition. However, the precise nature of the risk is not yet known.
• Neurotransmitters are chemicals that occur naturally in your brain. It is thought that if you have an imbalance of these chemicals, it may increase your risk of getting conditions such as panic disorder.

Fight or flight reflex

Some researchers believe that panic disorder is closely associated with your body's natural 'fight or flight reflex'.

This reflex is your body's way of protecting you from stressful and dangerous situations. In a dangerous situation, anxiety and fear trigger your body to release hormones, such as adrenalin. This causes your breathing and heart rate to increase, helping you to prepare you for the situation.

When you are faced with a dangerous or frightening situation, your body reacts in a very similar way to a panic attack. However, with panic disorder, there is usually no obvious trigger for your symptoms. Researchers believe that your fight or flight reflex may be triggered abnormally in people who have panic disorder.