Clinical Implications

Illicit opioid use to a large extent manifests via the illicit use of prescription opioids and typically includes polysubstance use. Physical and (or) mental health comorbidities are highly prevalent in illicit opioid user populations. Morbidity and (or) mortality risks are often associated with social marginalization. Limitations Little is known about the patterns and consequences of illicit opioid use in general populations. Owing to the marginalized and illegal status of illicit opioid users, information is available only from selective populations with limited potential for generalizability of data. The OPICAN study specifically builds largely on self-report and may be subject to bias. Objectives: To summarize key characteristics and consequences of illicit opioid use from the literature and to present corresponding data from a multisite sample of illicit opioid users in 5 Canadian cities (OPICAN study). Method: We undertook an overview of recent literature from North America, Australia, and Europe. We obtained data from the multicity OPICAN cohort study, which consisted of an interviewer-administered questionnaire, a standardized mental health instrument (the Composite International Diagnostic Intervie