Which symptom is typically not increased by stimulant medications?

Stimulant medications are primarily used to increase the levels of certain neurotransmitters in the brain, particularly dopamine and norepinephrine, which lead to heightened alertness, improved concentration, and increased physical activity. Heart rate, alertness, and breathing are physiological responses that often become elevated when stimulant medications are administered, as these drugs stimulate the central nervous system (CNS).

In contrast, sleepiness is not a symptom that is increased by stimulant medications; rather, these medications work to reduce fatigue and promote wakefulness. Therefore, sleepiness is the correct answer because it represents an effect opposite to what stimulants aim to achieve. By nature, stimulants are used to counteract drowsiness and enhance alertness, making it unlikely for such medications to contribute to increased sleepiness.