MedicalResearch.com Interview with: Alexander S. Hatoum, PhD Research Assistant Professor Institute for Behavioral Genetics Washington University in St. Louis     MedicalResearch.com: What is the background for this study? Response: It is well known that someone with one substance use disorder will have another sometime in their lifetime or concurrently.  Further, individuals that do manifest two or more substance use disorders in their lifetime have the most morbid conditions. However, research often ignores the comorbidity and focuses on diagnosis of one substance use disorder at a time (i.e. opioid use disorder or alcohol use disorder). We set out to identify the biology behind the cross-substance liability. (more…)