Alcohol is among the most used drugs and greatly impacts public health. More people over age 12 in the United States have used alcohol in the past year than any other drug or tobacco product, and alcohol use disorder is the most common type of substance use disorder in the United States.

Opioids are chemically related and interact with opioid receptors on nerve cells in the body and brain. Opioid pain relievers are generally safe when taken for a short time and as prescribed by a doctor. Because they produce euphoria in addition to pain relief, they can be misused.

Heroin is an opioid drug made from morphine, a natural substance taken from the seed pod of the various opium poppy plants grown in Southeast and Southwest Asia, Mexico, and Colombia. Heroin can be a white or brown powder, or a black sticky substance known as black tar heroin.

Cocaine is a powerfully addictive stimulant drug made from the leaves of the coca plant native to South America. Although health care providers can use it for valid medical purposes, such as local anesthesia for some surgeries, cocaine is an illegal drug. As a street drug, cocaine looks like a fine, white, crystal powder.

Methamphetamine is a stimulant drug usually used as a white, bitter-tasting powder or a pill. Crystal methamphetamine is a form of the drug that looks like glass fragments or shiny, bluish-white rocks. It is chemically similar to amphetamine (a drug used to treat attention-deficit/hyperactivity disorder [ADHD].

When used as prescribed by a doctor, prescription medicines can be helpful in treating many illnesses. Stimulants are helpful in managing attention-deficit/hyperactivity disorder (ADHD) and narcolepsy. Central nervous system (CNS) depressants treat anxiety, panic, and sleep disorders.