US Core currently defines profiles to support laboratory results, vital signs, and smoking status. Behavioral health and pain management are very important issues in the United States today, and assessments such as PHQ-2, PHQ-9, AUDIT-C, AUDIT-10, DAST-10, FACES, etc. are important for providing care in these areas. U.S. Core, however, doesn't explicitly support them since they would generally be in the "survey" category of Observation.

Please consider defining profiles to support these types of assessments. While FHIR Core Observation supports them (of course), a U.S. Core profile would help define the minimum requirements to better support interoperability and increase the likelihood of successful vendor adoption.