A drug addiction is defined as a chronic disease characterized by drug seeking and use that is compulsive and harmful. Repeated drug use can lead to changes in the brain that interfere with an individual's personality and urge them to continue to take drugs, which is why drug addiction is considered a relapsing disease since it is difficult to quit the abuse of drugs. Relapsing is common for people who are in recovery, but this doesn't mean that treatment does not work. People in recovery are simply more at risk to returning to drugs no matter how many years it has been since they initially took them.