Cannabis Use Is Associated With Suicidal Ideation Among Individuals With Opioid Use Disorder Receiving Opioid Agonist Therapy: Cannabis use is associated with suicidal behavior in the general population. This Canadian study investigated the association between cannabis use and suicidal ideation in cohort of participants aged 16 or older with opioid use disorder who were receiving opioid agonist therapy. This study raises concerns about the potential effect of cannabis on the psychological health of individuals with opioid use disorder.