Final answer:
A characteristic symptom of panic disorder is a sense of impending, unavoidable doom, which is part of the intense fear and discomfort that can peak within minutes during a panic attack.
Step-by-step explanation:
When discussing symptoms of panic disorder, it's important to highlight that a sense of impending, unavoidable doom is indeed one of the characteristic symptoms. People with panic disorder may experience intense periods of fear or discomfort that arise abruptly and peak within minutes. These panic attacks are accompanied by various symptoms, which can include a pounding heart, sweating, trembling or shaking, sensations of shortness of breath, feelings of choking, chest pain, nausea, feeling dizzy or light-headed, chills or heat sensations, paresthesia (numbness or tingling sensations), derealization or depersonalization (feeling detached from oneself or reality), fear of losing control or going crazy, and notably, a sense of impending doom. These symptoms can be so severe that individuals often feel they are having a heart attack or other life-threatening medical condition.