Pain is your body’s signal that something isn’t right. To help manage it, doctors often prescribe powerful opioids — but they’re not always the best option and can quickly lead to addiction. Illuminating the fine line between substance use and abuse, Dr. Jen Gunter explains what opioids do to your perception of pain, the risks they pose and the questions to ask your doctor about them. (For more on how your body works, tune in to her podcast, Body Stuff with Dr. Jen Gunter, from the TED Audio Collective.)