Question pretext
I am now going to ask you about your use of drugs. Remember that this is a confidential interview and your answers will in no way be linked to you. If you do not remember the answer to any of the questions, your best guess will do.
Literal question
In the past-30 days, how many days did you use it?
Interviewer instructions
*. Code as following (1) Once (2) 2 - 3 days a month (3) About once a week (4) 2 - 3 days a week (5) 4 - 6 days a week (6) Everyday (9) Don't know (0) Never