Social anxiety is normal for everyone, except when the anxiety begins to interfere with living a happy and healthy life. Social anxiety disorder (SAD), or social phobia, involves intense anxiety or fear about various social situations and is the third-most common mental health problem in the world today after alcoholism and depression.

About 1 in 8 people (12 percent) have suffered from SAD at some time in their lives. In a given year, about 7 out of every 100 (approximately 15 million) people suffer from this disorder.

Avoiding situations that might include being judged by others is a common behavior of those who suffer from SAD. The feelings that accompany this disorder include anxiety, high levels of fear, nervousness, automatic negative emotional cycles, racing heart, blushing, excessive sweating, dry throat and mouth, trembling, and muscle twitches.

In severe situations, people can develop a dysmorphia concerning part of their body (usually the face) in which they perceive themselves irrationally and negatively. People with SAD are often perceived as shy, quiet, backward, withdrawn, inhibited, unfriendly, nervous, aloof and disinterested.

Researchers have thought that social anxiety can be overcome, that cognitive-behavioral therapy literally changes brain circuitry and wiring, and that diligent cognitive-behavioral therapy for SAD will result in brain changes. Supporting this hypothesis, a study in 2013 included brain scan images showing directly where changes were noted in the brain before cognitive-behavioral treatment and after going through cognitive-behavioral treatment.

Medications can only temporarily change brain chemistry, which may be useful in some cases, but these scans showed the change that occurs in the brain as a result of basic cognitive-behavioral treatment intervention. The idea is that the combination of cognitive and behavioral therapy changes the brain, allowing those with SAD to overcome social anxiety.

A new study, however, sheds even more light on this disorder and on a specific serotonin transporter gene called gene SLC6A4, previously implicated in the development of social phobia. The SLC6A4 gene encodes a mechanism in the brain involved in transporting the messenger serotonin, which suppresses feelings of fear and depression and plays an important role in social phobia.

Together with the Clinic and Policlinic for Psychosomatic Medicine and Psychotherapy at the University Hospital Bonn, Dr. Andreas Forstner from the Institute of Human Genetics at the University of Bonn is conducting a study into the genetic causes of social phobia.

The researchers genotyped 321 patients with SAD and 804 controls without social phobia and carried out a single-marker analysis to identify a quantitative association between SAD and avoidance behaviors, focusing on single nucleotide polymorphisms (SNPs), where causes of genetic illnesses often lie. They investigated 24 SNPs thought to be the cause of social phobias and other mental disorders.

The patients provided information about their symptoms, including severity. Blood samples were taken to examine participants' DNA. The initial findings provide evidence that the serotonin transporter gene SLC6A4 is frequently correlated with anxiety-related traits. However, researchers are unclear about whether low levels of serotonin contribute to social anxiety or whether social phobia triggers a decrease in serotonin levels.

Genetic studies in SAD are rare, and only a few candidate genes have been implicated so far. This study is the largest association study probing the cause of social phobias to date. The researchers hope this research will help forge better diagnoses and treatment procedures for SAD.