Chart A
Main study sample diagram and exclusion criteria

15,154 respondents are 15 years old or older and part of the 2015 Canadian Tobacco, Alcohol, and Drugs Survey (CTADS) . 8,800 never used cannabis in their lifetime, 6,194 did.
Out of the 6,194 who did use cannabis in their lifetime, 2,078 used cannabis in the past 12 months, 4,114 did not.
Out of the 6,194 who did use cannabis in their lifetime, 1,091 used cannabis once, 5,095 more than once.
Out of these, 464 used cannabis for medical purposes in the past 12 months, 4,635 did not.
172 respondents were excluded because they did not know the answer, refused or are not stated.

The main study sample was 14,978, includes all non-medical users, including one time only users.
12,902 are non-user in the past year; 1,622 are non-medical only user in the past year; 454 are self-defined medical / non-medical user in the past year.

10 respondents who indicated that they did not use cannabis in the past 12 months but that they used cannabis for a self-defined medical purpose were dropped from the study sample as this questionnaire flow pattern was in error and resulted in them not being asked most other cannabis-related questions, including frequency of use and harms, etc.

A secondary sample of 14,879 was also created in which non-medical only cannabis users were further subdivided into repeat users, 99 one-time users excluded.