Information is collected using interviewer based questionnaires and kept in accessible files. The amount of time spent on each interview is minimized as much as possible. This is to enable many participants to be interviewed and to avoid delaying them unnecessarily. Each participant will have a file (hard copies) with all his/her information, including printed questionnaires with their information, kept in a fireproof, lockable cupboard in the department of clinical pharmacology, in the college of health sciences of the University of Zimbabwe. Upon completion of the study, data will be kept for at least 3 years. Only the principal investigator and co-investigators will have access to soft and hard copies of data.