Biological: Social anxiety disorder may be related to an imbalance of the neurotransmitter serotonin. Neurotransmitters are special chemical messengers that help move information from nerve cell to nerve cell in the brain. If the neurotransmitters are out of balance, messages cannot get through the brain properly. This can alter the way the brain reacts to stressful situations, leading to anxiety. In addition, social anxiety disorder appears to run in families. This means that the disorder may be passed on in families through genes, the material that contains instructions for the function of each cell in the body.
Psychological: The development of social anxiety disorder may stem from an embarrassing or humiliating experience at a social event in the past.
Environmental: People with social anxiety disorder may develop their fear from observing the behavior of others or seeing what happened to someone else as the result of their behavior (such as being laughed at or made fun of). Further, children who are sheltered or overprotected by their parents may not learn good social skills as part of their normal development.