Final answer:
A panic disorder is a mental health condition characterized by recurrent, unexpected panic attacks. Symptoms of panic disorder include feelings of immediate apprehension, terror, and impending doom.
Step-by-step explanation:
A panic disorder is a mental health condition characterized by recurrent, unexpected panic attacks. These panic attacks are marked by intense physical and psychological symptoms, such as rapid heart rate, shortness of breath, chest pain, feelings of impending doom, and a sense of losing control. The nurse recognizes symptoms of panic disorder, including feelings of immediate apprehension, terror, and impending doom (option 3). Other symptoms mentioned in the question, such as fatigue, muscle tension, nervousness, dry mouth, and restlessness, can also be present in individuals with panic disorder, but they are not exclusive to this condition.