Substance use can lead to addiction, but addiction can also manifest in behaviors such as gambling, sex, and work. The underlying process of addiction is the same regardless of the substance or behavior. Once someone has been severely addicted to a substance or behavior, they are more vulnerable to addiction to any substance or behavior. Addiction is driven by the pleasure-pain balance in the brain, and the brain circuitry for addiction is generalizable. It's important to recognize the signs of addiction and seek help if needed.