Addiction is a chronic brain disease that involves pathological pursuit of reward and relief through substance use and other behaviors, despite their negative consequences. The brain's reward center is activated by natural rewards like food and sex but becomes dysfunctional in addiction. Genetics and life experiences influence this. For addicts, nothing else stimulates the reward center normally. Continued substance use or behaviors cause biological, psychological, social, and spiritual problems. Prevention focuses on healthy activities with family and friends while treatment requires confronting the issue with care but also firmness when needed.