What could excessive use of certain drugs lead to in terms of physical appearance?

Excessive use of certain drugs can indeed lead to weight loss and narrowed pupils. Many drugs, particularly stimulants such as cocaine or methamphetamine, are known to suppress appetite, which can result in significant weight loss. This effect occurs because these substances can speed up metabolism and decrease the desire to eat.

Additionally, these drugs can cause physiological changes that affect the pupils of the eyes. Stimulants often lead to pupil constriction, or miosis, which results in narrowed pupils. This occurs as a direct response of the body's nervous system to the presence of these substances.

In contrast, other choices describe effects that are not typically associated with the excessive use of drugs. For example, weight gain and widened pupils is often linked to other conditions or substances that do not align with the impacts of drug abuse. Skin rashes and discoloration can occur with some drugs, but they are not universally applicable to all drug use. Lastly, an improved complexion and healthy glow is generally not a characteristic of drug abuse; rather, substance misuse usually has detrimental effects on skin health.