Drug addiction is a complicated problem. It is a chronic brain disease that compels a person to continue using a substance they know is harmful to them. Overcoming addiction is a challenge that often requires group support in an environment such as rehab. Common drugs that are used and abused are meth, cocaine, GHB, and even legal drugs like Xanax or DXM (cough medicine). The dangers of drug use are real. Follow the links below to find WebMD's comprehensive coverage about how drug use and abuse affects your body, how to overcome addiction, and more.