My friend sent her son to rehab for an addiction to pain meds, and when he came back home, he overdosed on heroin within two days. She says he never even touched heroin before he got there. Is it possible that her son was exposed to other drugs while he was in rehab, or did he just reach for the first drug he could find when he got out? I’m currently considering treatment centers for my son, but I am worried that if I send him to rehab, the same thing will happen. Is this common?