Genetics influence a person's brain biochemistry, and may make certain people more prone to problems with anxiety. The brain's biochemistry involves the brain's millions of nerve cells (called neurons) that constantly communicate with each other through chemicals called neurotransmitters.
Neurotransmitters are the brain's chemical messengers, and specific neurotransmitters help to regulate mood. Neurotransmitters are released from one neuron and attach to a receptor on another neuron. Sometimes there is interference with this process, such as if the receptor is blocked and unable to receive the neurotransmitter.
This interference can create an imbalance in the levels of the neurotransmitter in the brain, and can cause symptoms of anxiety. There are many kinds of neurotransmitters; two that are involved in anxiety are called serotonin and dopamine. When there's an imbalance of these chemicals, anxiety and other problems can occur.
Certain things that happen in a person's life can also set the stage for anxiety disorders. Frightening traumatic events that can lead to PTSD are a good example.
Early learning also plays a role. Growing up in a family where others are fearful or anxious can "teach" a child to view the world as a scary place. Likewise, if a child grows up in an environment that is actually scary or dangerous (if there is violence in the child's family or community, for example), the child may learn to be fearful or expect the worst.
The brain's automatic reaction to an anxiety-provoking situation also can fuel an anxiety disorder. Here's how this can happen: when a person senses danger (even if it doesn't turn out to be true danger), the brain quickly reacts by sending a signal to a small structure in the brain called the amygdala (pronounced: uh-mig-duh-luh). The amygdala immediately activates the body's automatic "fight or flight" response, and the body prepares itself for danger. This response is what triggers symptoms like sweating and a pounding heart.
Sometimes it turns out that as soon as the person processes the information in the thinking part of the brain (the cerebral cortex), which happens just moments later, the person realizes there's really no danger. The person then relaxes, and this fight or flight response stops.
But the amygdala is programmed to "remember" the trigger that set this process in motion in case it happens again. This is the brain's attempt to protect the person from future danger by keeping track of all cues that might signal danger. So, for example, if the person encounters the same thing that scared him once before (even if the person later realized it wasn't dangerous), the amygdala may activate the same anxiety reaction. It's possible for the amygdala to begin to overreact, and for the person to mistakenly interpret certain things as dangerous.
Reviewed by: D'Arcy Lyness, PhD
Date reviewed: August 2001