Press Release


Bob Young

For Release:

August 29, 2017

CWCI Examines Opioid Use in California Workers' Comp Claims Involving Mental Health Disorders

Oakland – A new California Workers’ Compensation Institute (CWCI) study 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.  Using data from 368,538 lost-time claims for work injuries that occurred during the 10-year span ending in December 2016, the study’s authors calculated the percentage of claims with and without mental health disorders in which opioids were dispensed, with results broken out by accident year at 6 different development periods (3, 12, 24, 36, 48 and 60 months post injury).  Among the findings:

  • Between one quarter and one third of California workers’ comp indemnity claims (with or without a mental health disorder) had opioids dispensed within three months of the injury, with opioids slightly less prevalent among the claims with mental health disorders during this acute injury phase.
  • By 12 months post injury, opioids were more prevalent in the claims with mental health disorders than in those without a mental health component for all accident years except 2015 and 2016; and at 24, 36, 48 and 60 months post injury, opioids were more prevalent among mental health claims from all 10 years.
  • The average number of opioid prescriptions per claim was higher for injured workers with mental health disorders at all stages of claim development in all 10 accident years, and widened as the claim aged, though looking at the average number of prescriptions at the same development periods across different accident years shows the volume of opioid prescriptions has diminished in recent accident years.
  • Claims with mental health disorders were more likely to have opioids introduced later in the claim, so at 5 years post injury, 60.7 percent of the claims with mental health disorders had involved opioids compared to less than half of the claims without mental health disorders.
  • The average potency of the opioids dispensed was significantly higher for injured workers with mental health disorders than for those without mental health disorders. For example, for AY 2011 injuries, the average morphine milligram equivalent (MME) per opioid prescription was 51.4 percent higher for claims with mental health disorders.

CWCI has published its study as a Spotlight Report, “Differential Use of Opioids in California Workers’ Compensation Claims with Mental Health Disorders.” The public can access the report at CWCI members and subscribers may also log in to to obtain a summary Bulletin.