It sounds like if you did not disclose this it would count as lying…Do I really have to disclose the treatment I have undergone for drug addiction in the past? What if I (shudders) don't tell them?
Application question, for reference: Have you ever required any treatment or counselling, or been the subject of any disciplinary action by an employer, relating to alcohol, drugs or gambling? (Russell-Cooke)
EDIT: I guess the answer lies in the term “required”, were you made to receive treatment as part of some sort of action plan or did you undertake it spontaneously?