While opioid addiction treatments, abstinence, and medication to decrease withdrawal symptoms are increasing in usage, opioid addiction remain a serious issue in this country. The issue began in the 1990s when laws governing prescriptions of opioid painkillers became more liberal and physicians began prescribing the popular painkillers as a first line defense for all minor aches and pains. Between 1997 to 2007, there was a 402% increase in the sales of opioids per person, including hydrocodone, hydromorphone, and oxycodone. Part of the issue comes from patients who ask for prescriptions but end up selling the drugs on the streets. Another problem is that pain management classes are not thoroughly taught in medical school to prepare physicians on how to deal with patients who need pain medication and whether opioids are the right option for all pains and patients. The opioid addiction problem has led to an increase in advocates for medical marijuana use. Medical marijuana provides pain relief, but according to supporters, does not lead to the same type of dependence, addiction, and destruction that opioids inevitably cause.