Fig. 1
From: Signals of increasing co-use of stimulants and opioids from online drug forum data
a Total number of Redditors who posted in the opioid-related subreddits each year from 2011 to 2020; b total number of people who co-use opioids and stimulants (PWCU), i.e., who posted about both opioids and/or opioid-related medications and stimulants; and c ratio of PWCU to total number of Redditors each year. Volume of participation in relevant subreddits in early years of the analysis is low; caution in interpreting trend should be applied