Denial is a psychological defense mechanism where a person refuses to accept reality or facts. This can occur in various situations, such as when someone is faced with a difficult truth, like a serious illness or the end of a relationship. By denying the reality, individuals may protect themselves from emotional pain or anxiety. In the context of addiction, denial can prevent individuals from recognizing the severity of their problem. For example, a person struggling with substance abuse might convince themselves that their use is not harmful, despite evidence to the contrary. This can hinder their ability to seek help and make necessary changes.