If you've ever had a panic attack, you'll know how frightening it is. But no matter how alarming your feelings are, it's important to know that they won't harm you. And they usually go away after a few minutes.

Key points for people with panic disorder

• Panic attacks are frightening but they won't harm you.
• If you get panic attacks often, and worry all the time about when you'll have the next one, you may have panic disorder.
• Panic disorder is very common. It affects about 1 in 50 people in the UK.
• Women are more likely than men to get panic disorder.
• People usually start having panic disorder in their late teens or early 20s.
• Most people with panic disorder get better if they have treatment. But the condition may come and go.

It's normal to feel scared and panicky when you're in danger. These feelings are your body's in-built protection system. They can save your life when you're in dangerous situations. For example, if you're about to cross the road and a bus is coming towards you, it's fear that makes you react quickly and get out of the way. Fear can also give you extra drive. For example, when you're preparing for an exam, your nerves can give you the push you need to study harder.

Your response to fear involves many parts of your body, including your brain, the rest of your nervous system, your muscles and your circulatory system. Lots of things happen to your body when you're nervous or scared.

• Part of your body is put on high alert. You stop everything else you're doing and focus on the thing you're worried about. Two chemicals in your nervous system are important for this reaction. They are called adrenaline and serotonin.
• Your body gets ready to escape from danger. The chemical adrenaline is pumped into your blood. Adrenaline is sometimes called the 'fight or flight' hormone, because it tells your body to be ready to deal with danger. You might fight an attacker, for example. Or you might move quickly away from a fire.
• Your heart beats faster. This pumps more blood around your body to help your muscles work better and escape danger.
• You may tremble and go pale. The extra adrenaline draws blood away from your skin and redirects it to your muscles, making you more able to fight or run away.
• You may need to urinate or empty your bowels. This is because adrenaline relaxes your bladder and bowels.

All of these reactions are a normal response to stress or fear. And while they're happening, another part of your brain checks to see whether the thing you were afraid of is actually happening. If it doesn't happen, or if the danger passes, your fear responses will fade away.

What happens if you have panic disorder?

If you get panic attacks, you suddenly feel absolutely terrified. The only difference between the feelings you have during a panic attack and a normal response to fear is that you get panic attacks when there's nothing to be afraid of.

You may have panic disorder if you start worrying all the time about when you're going to have another panic attack and if you change your usual routine in order to try to avoid having panic attacks.

Doctors aren't sure why the normal reaction to fear can be triggered for no reason in some people.

Why me?

Certain things increase your chances of getting panic disorder. Doctors call these risk factors. Some of the main risk factors for panic disorder are going through a stressful event, such as taking important exams. Women are more likely than men to get panic disorder. Panic attacks tend to start in the late teens or early 20s, so being this age is another risk factor.

What else can cause a panic attack?

Panic attacks aren't always caused by panic disorder. Sometimes there's another cause. Drinking too much coffee or taking certain drugs (both legal and illegal ones) can cause panic attacks. Some medical conditions, such as an overactive thyroid, may also make you panic. If your doctor (your GP or a specialist in the hospital) finds a specific medical cause for your panic attacks, then you don't have panic disorder. Treating the cause will usually make the panic attacks go away.

If you only get panic attacks in social situations, such as when you're in a big group of people or travelling on a crowded bus or train, you may have another condition, such as a phobia, obsessive-compulsive disorder or post-traumatic stress disorder.

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