Addiction refers to a state of craving for a particular external substance which, for various reasons, the addicts feels he or she needs and cannot do without. Addicts often act in ways that damage themselves or others in order to get and use the desired substance.
Addiction is a chronic but treatable brain disorder. Once addicted to a drug, the individual cannot control his need for the drug even when he faces health problems or social / legal consequences.
This lack of control & behavioral changes is the result of alcohol/drug-induced changes in the brain. Imaging studies on brain show that addiction severely alters the areas of the brain which are critical to decision making, learning, memory and behavioral control.
It is because of this the substance abusers exhibit compulsive and destructive behavior patterns. Also, drugs modify the brains of addicted people in such a way that absence of drug leaves him in a state of deprivation where taking the drug becomes indispensable for survival.
No one takes alcohol/drugs to become an addict. There is a mis-belief that he can recognize when addiction is developing and stop using on time. But this never happens and the person gets addicted in a period which varies with the substance abused.
As addicts, we use many mind-altering, mood-changing substance causes a problem in any area of life. Addiction is a disease which involves more than simple drug use. Some of us believe that our disease was present long before the first time we used.