A substance use disorder (SUD) is defined by the American Psychiatric Association a complex a condition in which there is uncontrolled use of a substance despite harmful consequences. Individuals with substance use disorders, formerly referred to as addiction, have an intense focus on using a certain substance(s) and keep using to the point where their ability to function in day-to-day life becomes impaired.  People with a substance use disorder may have distorted thinking and behaviors, as substance use can change areas of the brain related to judgment, decision making, learning, memory, and behavioral control.