Among the listed symptoms, which one is indicative of a panic attack?

Trembling is a well-documented symptom that can occur during a panic attack. Panic attacks are characterized by a sudden onset of intense fear or discomfort, often leading to physiological responses that can include trembling, shaking, heart palpitations, shortness of breath, and dizziness. The body's fight-or-flight response is triggered, resulting in various involuntary physical reactions, such as trembling. Recognizing this symptom is essential for identifying panic attacks and understanding the associated anxiety disorders.

In contrast, excessive laughter is not typically a symptom of a panic attack; rather, it can signify a different emotional state, often linked to nervousness or disconnection from the situation. Increased focus generally suggests a calm and controlled state of mind, far from the overwhelming experience of a panic attack. Delayed reactions may indicate a lack of immediate response to a stimulus but do not directly relate to the acute symptoms of panic. Thus, trembling stands out as the clear indicator of a panic attack among the options provided.