Opioids are a class of powerful drugs including illegal substances such as heroin and prescription medications such as oxycodone, hydrocodone, and morphine. Doctors prescribe opioids for pain relief in patients recovering from serious injury or surgery, or in patients suffering from debilitating diseases such as cancer. Young people who abuse opioids usually obtain them from family or friends with prescriptions, though they are also sold illegally. As with other addictive substances, young people are more susceptible to addiction to opioids because their brains are still developing.