Which symptom is often associated with anxiety in the context of stimulant use?

The correct choice highlights a symptom that is commonly experienced by individuals using stimulants, which can significantly affect their emotional state. Stimulants, such as caffeine, nicotine, and certain prescription medications, can increase heart rate and activate the body's stress response, which often leads to feelings of worry or unease. This heightened state of arousal can trigger or exacerbate anxiety symptoms, making it difficult for individuals to feel calm or at ease.

The other options describe feelings or behaviors that are generally not associated with anxiety caused by stimulant use. Feelings of tranquility would denote a state of calmness, which contradicts the anxiety response. Increased appetite is typically a symptom associated with depressants rather than stimulants, which often suppress appetite. Improved social interactions are also not a direct result of stimulant use; in fact, anxiety can lead to social withdrawal or discomfort in social situations. Therefore, the feelings of worry or unease stand out as the symptom closely related to anxiety in the context of stimulant use.