I have a "flesh purity" pawn with the "Drug use: prohibited" precept which as a policy that makes them take penoxcicyling every 5 days. They do take it and then get negative mood for taking a drug. I can not order them to take it manually, but the schedule seems to still work.
Drug in effect: https://steamuserimages-a.akamaihd.net/ugc/1822271431476673530/2DBF0BAA20B87C822BFAFCCCC474BF1826B32C9C/
Manual prohibition + mood debuff: https://steamuserimages-a.akamaihd.net/ugc/1822271431476674885/02F6FA059CD5F655265909883D2A2EF0A870A634/
Schedule: https://steamuserimages-a.akamaihd.net/ugc/1822271431476675145/F62327842A36B4428E297CB4D19A4D476ABF050B/
Ideology with precept: https://steamuserimages-a.akamaihd.net/ugc/1822271431476693205/4B07F0113232943D862119DA4F62AEB95633E63E/
Both DLCs, no mods used.
Thanks for the bug report glass zebra. I'll see if this is an oversight or just a way for you to get around restrictions for necessary drugs and just take the mood hits.