A CWCI study that tracks changes in the prevalence, volume and strength of opioid prescriptions in California work injury lost-time claims that involve a mental health component, and compares those results to other indemnity claims that have no mental health component. The study uses data from 368,538 lost-time claims for work injuries that occurred during the 10-year span ending in December 2016, to measure the percentage of claims with and without mental health disorders in which opioids were dispensed, and breaks out the results for each accident year at 6 different development periods (3, 12, 24, 36, 48 and 60 months post injury).