Long-term use of opioids changes how the brain and body work, and these changes can affect your actions and thoughts. Changes in your actions and thoughts may lead to more drug use, which then leads to more changes to your brain and body. This cycle is likely to make the addiction worse over time and make treatment and sobriety more difficult to achieve. We are trying to better understand this cycle so that we can develop new and better treatment options in the future. Active users and those on opioid medications are eligible. The research is done in person at Stony Brook University Medical Center located in Stony Brook, NY.