Drug addiction is a chronic disease characterized by compulsive, or uncontrollable, drug seeking and use despite harmful consequences and changes in the brain, which can be long lasting. These changes in the brain can lead to the harmful behaviors seen in people who use drugs. Drug addiction is also a relapsing disease. Relapse is the return to drug use after an attempt to stop.
The path to drug addiction begins with the voluntary act of taking drugs. But over time, a person’s ability to choose not to do so becomes compromised. Seeking and taking the drug becomes compulsive. This is mostly due to the effects of long-term drug exposure on brain function. Addiction affects parts of the brain involved in reward and motivation, learning and memory, and control over behavior.