Which of the following terms refers to heightened energy levels indicative of stimulant use?

The term that refers to heightened energy levels indicative of stimulant use is excitation. Stimulants, such as caffeine, amphetamines, and cocaine, typically increase alertness, energy, and overall activity levels, leading to a state of excitement or euphoria. This state can be characterized by increased heart rate, elevated mood, and enhanced physical activity. Excitation captures this essence, as it reflects the heightened arousal and energy that are common physiological and psychological responses associated with stimulant consumption.

In contrast, restlessness may imply an inability to relax or stay still, and while it can be related to stimulant use, it doesn't specifically encapsulate the broader sense of energy or euphoria. Fatigue indicates a lack of energy or tiredness, which is the opposite of what is experienced during stimulant use. Calmness refers to a state of tranquility and relaxation, which is not associated with the stimulating effects that heighten energy levels. Overall, excitation accurately describes the elevated energy and arousal state following the use of stimulants.