Drug Use Addiction- Addiction is a condition of being addicted to a particular substance, thing, or activity. What is the connection between addiction and the brain? The human brain wants us to keep doing things that we need or enjoy. Drugs that people use or misuse excite the parts of the brain thay make you feel good. Once you take a drug, your brain gets used to it and then you need to take more of the drug to get the same good feeling. Soon, your brain and body feel normal with the drug, and sick or not normal without the drug.