DRUGS ARE POWERFUL substances. They can strongly alter people's moods and actions. More importantly, the effects of drug use can have serious short-term and long-term effects—for people's physical and emotional health, for their family and social relationships, and for their ability to learn while in school and to hold down jobs.

Effects on physical health

The physical effects vary with each kind of drug. Regular marijuana use, for example, can cause lung disease, accelerate the heartbeat, and increase blood pressure. It can also interfere with judgment, motor skills, and memory. Cocaine speeds up the heart rate while at the same time constricting the blood vessels. This forces the blood vessels to handle an additional flow of blood, which can lead to a heart attack, seizure, or stroke.

Whatever the drug, regular use can lead...