What is an addiction? What does this mean? How do people become addicted?

"Substance dependence When an individual persists in use of alcohol or other drugs despite problems related to use of the substance, substance dependence may be diagnosed. Compulsive and repetitive use may result in tolerance to the effect of the drug and withdrawal symptoms when use is reduced or stopped. This, along with Substance Abuse are considered Substance Use Disorders..."

In medical terminology, addiction is a state in which the body relies on a substance for normal functioning and develops physical dependence.

A bit of history...

When this substance is suddenly removed, it will cause withdrawal, a characteristic set of signs and symptoms. The term 'addiction' was first used in 1906, in reference to opium (although there is an isolated instance recorded from 1779, refering to tobacco). The first use of the adjective 'addict' (with the meaning of 'delivered, devoted') was in 1529 and comes from the Latin addictus, pp. of addicere ('deliver, yield, devote,' from ad-, 'to' + dicere, 'say, declare').[1]

DRUG ADDICTION

Drug addiction is widely considered a pathological state.

TERM USAGE
However, common usuage of the term addiction has spread to include a wider range of meanings, including ones asociated with psychological dependence. It is used to describe a recurring compulsion by an individual to engage in some specific activity, despite harmful consequences to the individual's health, mental state or social life.

"Addiction is a primary, progressive, chronic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. The disease is often progressive and fatal. It is characterized by impaired control over use of the substance, preoccupation with the substance, use of the substance despite adverse consequences, and distortions in thinking."

HOW DO PEOPLE BECOME ADDICTED?