Most Americans have used alcohol or an illicit drug in their lifetime. Most will never develop a substance use disorder. Substance use occurs along a continuum from abstinence to addiction. Some people may find themselves moving along this continuum at various points in their lives. The majority of people will manage their substance use without seeking professional help. Some people simply need harm reduction support and tools to be safer. Others who develop issues with their use will choose to pursue professional substance use disorder treatment.