It is also known as substance use disorder, and it occurs when a person's behaviour and brain are damaged, resulting in an inability to manage their use of a legal or illegal drug or treatment. Marijuana, alcohol, and nicotine are all examples of drugs that people abuse. Addicts are unable to distinguish between the harmful consequences of using these drugs. Drug addiction can affect people of any age, gender, or socioeconomic level. Factors that can influence the likelihood and pace with which an addiction develops: