This is the ValueSet that contains all the codes in x_ActMoodDocumentObservation (http://terminology.hl7.org/ValueSet/v3-xActMoodDocumentObservation) and x_ActMoodDocumentObservation (http://terminology.hl7.org/ValueSet/v3-xActMoodDocumentObservation). E.g. what you have to deal with if you get resources containing codes in either of them