Substance use disorder is a condition characterized by the harmful or hazardous use of substances such as alcohol, nicotine, prescription medications, or illicit drugs. Individuals with substance use disorder may experience difficulty controlling their use of the substance, continue to use it despite adverse consequences, and may experience cravings and withdrawal symptoms when not using the substance. Research in the area of substance use disorder aims to understand the underlying causes of addiction, develop effective prevention strategies, and improve treatments for individuals struggling with substance use. This research often involves studying the effects of different substances on the brain and behavior, identifying risk factors for developing a substance use disorder, and evaluating the effectiveness of interventions such as therapy, medication, and harm reduction programs. By gaining a deeper understanding of substance use disorder, researchers hope to improve outcomes for individuals affected by this condition and reduce its overall impact on society.