As with all other unspecified diagnoses, the codes for unspecified psychoactive substance use (F10.9-, F11.9-, F12.9-, F13.9-, F14.9-, F15.9-, F16.9-, F18.9-, F19.9-) should only be assigned based on provider documentation and when they meet the definition of a reportable diagnosis (see Section III, Reporting Additional Diagnoses).