SAD (Smoking, Drugs and Alcohol)

Drugs

A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.
In pharmacology, a drug is "a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being." Drugs may be prescribed for a limited duration, or on a regular basis for chronic disorders.
Recreational drugs are chemical substances that affect the central nervous system, such as opioids or hallucinogens. They may be used for perceived beneficial effects on perception, consciousness, personality, and behavior. Some drugs can cause addiction and habituation.

Drugs are usually distinguished from endogenous biochemicals by being introduced from outside the organism.[citation needed] For example, insulin is a hormone that is synthesized in the body; it is called a hormone when it is synthesized by the pancreas inside the body, but if it is introduced into the body from outside, it is called a drug.[citation needed]

Many natural substances such as beers, wines, and some mushrooms, blur the line between food and drugs, as when ingested they affect the functioning of both mind and body.
Recreational drugs use is the use of psychoactive substances to have fun, for the experience, or to enhance an already positive experience. National laws prohibit the use of many different recreational drugs and medicinal drugs that have the potential for recreational use are heavily regulated. Many other recreational drugs on the other hand are legal, widely culturally accepted, and at the most have an age restriction on using and/or purchasing them. These include alcohol, tobacco, betel nut, and caffeine products.
The spiritual and religious use of drugs has been occurring since the dawn of our species. Drugs that are considered to have spiritual or religious use are called entheogens. Some religions are based completely on the use of certain drugs. Entheogens are mostly hallucinogens, being either psychedelics or deliriants, but some are also stimulants and sedatives.