Pazcoguin v. Radcliffe, 292 F.3d 1209, as amended on denial of rehearing and rehearing en banc, 308 F.3d 934(9th Cir.2002) (upholding exclusion based on admission of smoking marijuana in Philippines made during immigration medical examination).      For the medical grounds of inadmissibility, the CDC Technical Instructions for Medical Examination of Aliens state that experimentation, "e.g., a single use of marijuana or other non-prescribed psychoactive substances," is not considered to be drug abuse under INA 212(a)(1). It is unlikely, however, that any medical examiner would exercise favorable discretion for an adjustment applicant who refuses to answer questions about what drug crimes they have committed.      For the criminal ground of inadmissibility, whether this is an admission of committing a crime related to a controlled substance depends on the dates, the jurisdiction, and the particular circumstances of the conduct involved, whether lab tests were done to identify the substances, etc., to determine whether all the essential elements have been admitted.  For example, under federal law, and in some state jurisdictions, mere use, without possession, is not a crime.  If the client is not qualified to determine the identity of the substances s/he consumed, s/he may not be able to admit that they were in fact controlled substances, given the many counterfeit substances purveyed on the street these days, and the unreliability of some drug dealers.