Neurobiology of Drug Addiction. Drug addiction is a chronic relapsing disorder that is caused by effects of addictive drugs on the brain. The seminar will consider 4 major drug addictions, including cocaine, heroin, alcohol, and nicotine. Readings and discussions on these addictions will cover the following topics: 1) symptom profiles; 2) neurobiological factors that contribute to the development of the disease; and 3) potential treatments.