Evidence that availability affects drug use or heavy drug use is difficult to assemble. Apparently no studies of physical or perceived availability have been made, e.g. studies of how street availability, level of police seizures or ease of purchase relates to drug use. Also physicians, pharmacists and nurses have higher rates of drug addiction than other professionals, presumably because drugs are more accessible to them in their daily work. On the other hand opiate drug use and addiction are often found not among the farmers who grow poppies but among those who live far away. For example, opiate addiction has been uncommon in Turkey where a great deal of the world's supply of licit opium used to be produced.
Opium addiction is believed to be more common among many of the producers in Asian countries.
However, general statements are difficult to make about availability and drug use. Students were asked to state how difficult it would be for them to obtain various drugs including alcohol. From each of 7 districts, Boards of Education were selected at random with their numbers proportionate to the total Ontario student enrolment. Schools were chosen from selected boards by a random method. The selection of classes was made in consultation with the school principal to be representative of all students in a grade.