Social anxiety disorder (SAD; also known as social phobia) describes an intense fear and avoidance of negative public scrutiny, public embarrassment, humiliation, or social interaction. This fear can be specific to particular social situations (such as public speaking) or, more typically, is experienced in most (or all) social interactions. Roughly 7%. of American adults have Social anxiety disorder, and more than 75% of people experience their first symptoms in their childhood or early teenage years. Social anxiety often manifests specific physical symptoms, including blushing, sweating, rapid heart rate, and difficulty speaking. As with all phobic disorders, those suffering from social anxiety often will attempt to avoid the source of their anxiety; in the case of social anxiety this is particularly problematic, and in severe cases can lead to complete social isolation.