Addiction is a neuropsychological disorder characterized by a persistent and intense urge to engage in certain behaviors, often usage of a drug, despite substantial harm and other negative consequences. Repetitive drug use often alters brain function in ways that perpetuate craving, and weakens self-control.

Some habits or social behaviors look like addiction. But in the case of an addiction, a person will typically react negatively when they don’t get their “reward.” For example, someone addicted to coffee can experience physical and psychological withdrawal symptoms such as severe headaches and irritability.