Addiction is a compulsion to repeat a behaviour regardless of its consequences

Addiction is a compulsion to repeat a behaviour regardless of its consequences. A person who is addicted is sometimes called an addict.

There is a lack of consensus as to what may properly be termed ‘addiction.’ Some within the medical community maintain a rigid definition of addiction and contend that the term is only applicable to a process of escalating drug or alcohol use as a result of repeated exposure. However, addiction is often applied to compulsive behaviors other than drug use, such as overeating or gambling. In all cases, the term addiction describes a chronic pattern of behaviour that continues despite the direct or indirect adverse consequences that result from engaging in the behavior. It is quite common for an addict to express the desire to stop the behaviour, but find himself or herself unable to cease.

Addiction is often characterized by a craving for more of the drug or behavior, increased physiological tolerance to exposure, and withdrawal symptoms in the absence of the stimulus. Many drugs and behaviours that provide either pleasure or relief from pain pose a risk of addiction or dependency.

Source