Your brain focuses on some alleged thread, for instance, a very scary thought that was floating somewhere at your subconscious. Your thalamus – the part of the brain responsible for regulating consciousness, sleep and alertness – transfers that information to your amygdala – the part of the brain responsible for emotional reactions, decision-making and memory – which marks it as “danger” and sends a signal to your sympathetic nervous system, activating the fight-or-flight response.
Social anxiety disorder (previously called social phobia): People with social anxiety disorder have a general intense fear of, or anxiety toward, social or performance situations. They worry that actions or behaviors associated with their anxiety will be negatively evaluated by others, leading them to feel embarrassed. This worry often causes people with social anxiety to avoid social situations. Social anxiety disorder can manifest in a range of situations, such as within the workplace or the school environment.