He is a medical sociologist who has been conducting research and harm-reduction based intervention development on opioid-related overdose, hepatitis C transmission, and sexually transmitted infections among drug users in Australia and the United States since 1997. Dr. Davidson's current work includes a NIH/NIDA funded R01 study examining impacts of Sheriff Department use of naloxone to respond to opioid overdose in San Diego County, and a UC Criminal Justice & Health Consortium Pilot grant exploring the impact of a Los Angeles County program to provide community-based care rather than incarceration for individuals who have been charged with misdemeanor offences but who are incompetent to stand trial.