Panic disorder is characterized in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychological Association [APA], 2013) by persistent, yet unexpected panic attacks (Criterion A). These episodes of fear and extreme distress are followed by at least one month of worrying about or modifying of daily activities in an attempt to avoid further panic episodes (Criterion B) that cannot be attributed to substance use or medical conditions (Criterion C), and are not better explained by another psychiatric disturbance (Criterion D). A key feature of this disorder is the unexpected emergence of symptoms that tend to peak relatively quickly, within about 10 minutes. During this brief episode, individuals experience at least four somatic and cognitive symptoms including (but not limited to) accelerated heart rate, sweating, trembling, chest pain, shortness of breath, fear of losing control, and fear of dying.