<human>:  How would you define anxiety disorder?
<bot>: Anxiety disorder is a type of mental disorder characterized by feelings of worry, anxiety, or fear that are strong enough to interfere with one's daily life. Symptoms of an anxiety disorder can include restlessness, fatigue, difficulty concentrating, irritability, muscle tension, sleep disturbance, and difficulty controlling the worry. People with an anxiety disorder may also experience physical symptoms such as rapid heartbeat, sweating, trembling, and feeling of being out of breath.