Addiction is a psychological and physical dependence on a substance or behavior that leads to compulsive and uncontrollable use, despite negative consequences. It is characterized by a strong craving or desire to engage in the addictive behavior or consume the substance, and an inability to stop or reduce use even when it causes harm to oneself or others. Addiction can affect various aspects of a person's life, including their relationships, work, health, and overall well-being. It is a chronic and relapsing condition that requires professional treatment and ongoing support to manage and overcome.