A person suffering from drug addiction has difficulty exercising self-control. It also makes it difficult for them to resist the urge to use drugs. This is due to the brain changes that occur with drug abuse. Drug addiction is a persistent, ongoing condition.
Other chemical circuits and brain systems can be altered by long-term drug use. This affects cognitive processes such as memory, stress management, learning and behaviour. These negative effects are common in addiction. Many drug addicts continue to use drugs even though they know the risks.
The brain's chemical systems and circuits can also be affected by long-term drug use. This can lead to changes in learning, judgement, decision making, stress, memory, behaviour and other factors. These bad things are not unknown to many drug addicts, but they continue to use drugs. This is the nature addiction.