On Wednesday, two California counties — Orange and Santa Clara — filed a lawsuit against five of the world's biggest pharmaceutical companies, alleging they are responsible for an epidemic of prescription pain killer addiction that is killing thousands of Americans.

It's a problem that has hit California disproportionately, according to the complaint. The issue of prescription medication abuse was the subject of an investigative series by the Los Angeles Times that found that half of all prescription drug-related deaths in Southern California involved drugs that had been legally prescribed by a doctor.

The series looks into the role of doctors, pharmacists and the oversight organizations tasked with monitoring them in the prescription drug abuse epidemic.