Everybody has anxiety from time to time. It's only natural that a person would be anxious while being interviewed for an import job, before giving a speech, or if a disaster threatened their home. However, there are anxiety disorders that have a negative impact on people's daily lives. This is the type of anxiety that needs special attention.
People with anxiety disorders will basically imagine possible scenarios of things that have not happened yet, but their mental and physical response will be as if the scenario is real and happening. In mild cases, the person can cope with these feelings fairly well, and there is little impact on their lives. Those with moderate to severe cases will be in a near-constant state of anxiety. This causes them to avoid situations, and they may choose to not leave their home.
The symptoms of anxiety are quite varied, and they are often confused for other conditions. This can actually add to the sufferer's anxiety because they start thinking that something is seriously wrong, when the reality is that they are having an anxiety or panic attack. While such an attack is unpleasant, it is not life-threatening. Here are just a few symptoms related to anxiety: heart palpitations, shortness of breath, chest pain, headaches, fatigue, stomach pains, and nausea. As you can see, it would be easy to think some of these symptoms are serious, so, unless you have been told otherwise by your doctor, it is best to seek immediate medical treatment if you think it's serious.
Here is an example of how somebody with anxiety perceives and thinks about things:
Let's say the person is driving to work and they suddenly wonder if they left the stove on. Most people would either reassure themselves that the stove was off, or not care all that much if it was left on because the chances of something happening would be remote (whether this is true or not isn't the point). A person with anxiety would worry about the stove being on, but it wouldn't stop there. They would imagine what would happen if it got so hot that the curtains on the other side of the kitchen caught on fire; and what if the house burned down; and maybe one of the kids will home early from school and get caught in the fire, and so on. They then go back home to make sure the stove is off.
What their thinking did is quickly snowballed from a simple thought into an imagined tragedy, and even though it's imagined, their body reacts as though the threat is real.
Without the proper treatment for anxiety, there is nothing the sufferer can do about this type of thinking. It's more like a chemical imbalance than anything else. The good news is that there are several treatment options for anxiety. It's just a matter of getting help and finding the best treatment for the individual.