Which of the following is a symptom of a panic attack?

Palpitations are a well-documented symptom of a panic attack and are included in the DSM-5-TR criteria for diagnosing panic disorder. During a panic attack, individuals may experience a rapid heartbeat or a sensation that their heart is pounding. This physiological response is part of the body's fight-or-flight reaction to perceived danger. Panic attacks can happen unexpectedly and can provoke feelings of intense fear or discomfort, often leading to other physical symptoms such as shortness of breath, chest pain, or dizziness.

In contrast, the other options involve symptoms that are not characteristic of panic attacks. Persistent sadness can relate to mood disorders like depression, excessive worry is a key symptom of anxiety disorders, and social withdrawal may be associated with various mental health issues but not panic attacks specifically. Therefore, the relevance of palpitations as a symptom distinctly aligns it with the experience of panic attacks, making it the correct answer in this context.