What is a common effect of stimulants on a person’s behavior?

Stimulants are substances that elevate mood, increase energy, and enhance alertness in individuals using them. They work by increasing the levels of certain neurotransmitters in the brain, such as dopamine and norepinephrine, which lead to heightened arousal and activity. People often experience greater focus and enhanced cognitive functions when under the influence of stimulants, making increased energy and alertness a hallmark effect of these substances.

While feelings of euphoria can also be associated with stimulants, the most consistent and fundamental impact is the increase in energy and alertness, which is why this response is recognized as the most common effect. The other options—excessive sleeping and feelings of relaxation—are typical of depressants or other classes of drugs rather than stimulants, further solidifying why the correct choice pertains specifically to energizing effects.