First of all, everyone has some degree of social anxiety. But where does shyness end and social anxiety disorder begin? It's not always clear, but a good guide is when the severity of social anxiety is high enough to substantially impair social or work functioning. The actual level of impairment can be difficult to assess, however, because many sufferers have almost unconsciously arranged their lives to minimize social interactions. Friends and family may have a better perspective than the individual suffering.

There are three different levels of social anxiety disorder.

Performance (or non-generalized) social anxiety disorder affects individuals only when they are performing in front of others. An example is severe anxiety or active avoidance of public speaking.

Generalized social anxiety disorder affects a person in many different social situations, from going to a party to speaking with their boss. The generalized type is the most common and best studied.

Avoidant personality disorder is considered by many anxiety specialists to be the most severe form of social anxiety. It usually starts at an early age and is much more common in males. Because it causes severe impairment in social functioning, these individuals have few friends and rarely marry. Fortunately, they respond to the same medications and behavioral treatments as those with generalized social anxiety disorder.