Anxiety is an affective reaction that can manifest in various forms and is not only completely normal but also biologically desired and life-saving. On the other hand, fears and anxiety reactions can be inappropriate in context and may present as a mental disorder. Historically, anxieties have been subject to changing classifications and meanings from the very beginning. Moreover, anxiety reactions and fears can be evaluated very differently on an individual basis. According to all current epidemiological studies, anxiety disorders are among the most common mental disorders today. The conditions for their development are complex. Current knowledge indicates that psychological factors, social circumstances, and neurobiological mechanisms all play an important role. Due to the often prominent physical symptoms of anxiety, patients are frequently found.